Merge pull request #1729 from OpenRefine/json-engineconfig

Store engine configuration in dedicated class

extensions/wikidata/src/org/openrefine/wikidata/commands/PerformWikibaseEditsCommand.java

@@ -25,9 +25,9 @@ package org.openrefine.wikidata.commands;
 
 import javax.servlet.http.HttpServletRequest;
 
-import org.json.JSONObject;
 import org.openrefine.wikidata.operations.PerformWikibaseEditsOperation;
 
+import com.google.refine.browsing.EngineConfig;
 import com.google.refine.commands.EngineDependentCommand;
 import com.google.refine.model.AbstractOperation;
 import com.google.refine.model.Project;
@@ -35,7 +35,7 @@ import com.google.refine.model.Project;
 public class PerformWikibaseEditsCommand extends EngineDependentCommand {
 
     @Override
-    protected AbstractOperation createOperation(Project project, HttpServletRequest request, JSONObject engineConfig)
+    protected AbstractOperation createOperation(Project project, HttpServletRequest request, EngineConfig engineConfig)
             throws Exception {
         String summary = request.getParameter("summary");
         return new PerformWikibaseEditsOperation(engineConfig, summary);

extensions/wikidata/src/org/openrefine/wikidata/operations/PerformWikibaseEditsOperation.java

@@ -49,6 +49,7 @@ import org.wikidata.wdtk.wikibaseapi.WikibaseDataFetcher;
 import com.fasterxml.jackson.databind.ObjectMapper;
 
 import com.google.refine.browsing.Engine;
+import com.google.refine.browsing.EngineConfig;
 import com.google.refine.history.Change;
 import com.google.refine.history.HistoryEntry;
 import com.google.refine.model.AbstractOperation;
@@ -65,7 +66,7 @@ public class PerformWikibaseEditsOperation extends EngineDependentOperation {
 
     private String summary;
 
-    public PerformWikibaseEditsOperation(JSONObject engineConfig, String summary) {
+    public PerformWikibaseEditsOperation(EngineConfig engineConfig, String summary) {
         super(engineConfig);
         Validate.notNull(summary, "An edit summary must be provided.");
         Validate.notEmpty(summary, "An edit summary must be provided.");
@@ -79,7 +80,8 @@ public class PerformWikibaseEditsOperation extends EngineDependentOperation {
         if (obj.has("summary")) {
             summary = obj.getString("summary");
         }
-        return new PerformWikibaseEditsOperation(engineConfig, summary);
+        return new PerformWikibaseEditsOperation(
+                EngineConfig.reconstruct(engineConfig), summary);
     }
 
     @Override
@@ -93,7 +95,7 @@ public class PerformWikibaseEditsOperation extends EngineDependentOperation {
         writer.key("summary");
         writer.value(summary);
         writer.key("engineConfig");
-        writer.value(getEngineConfig());
+        getEngineConfig().write(writer, options);
         writer.endObject();
     }
 

extensions/wikidata/tests/src/org/openrefine/wikidata/operations/PerformWikibaseEditsOperationTest.java

@@ -32,6 +32,7 @@ import org.openrefine.wikidata.testing.TestingData;
 import org.testng.annotations.BeforeMethod;
 import org.testng.annotations.Test;
 
+import com.google.refine.browsing.EngineConfig;
 import com.google.refine.history.Change;
 import com.google.refine.model.AbstractOperation;
 import com.google.refine.model.Recon;
@@ -58,7 +59,7 @@ public class PerformWikibaseEditsOperationTest extends OperationTest {
     
     @Test(expectedExceptions=IllegalArgumentException.class)
     public void testConstructor() {
-        new PerformWikibaseEditsOperation(new JSONObject("{}"), "");
+        new PerformWikibaseEditsOperation(EngineConfig.reconstruct(new JSONObject("{}")), "");
     }
 
     @Test

extensions/wikidata/tests/src/org/openrefine/wikidata/schema/WikibaseSchemaTest.java

@@ -55,6 +55,7 @@ import org.wikidata.wdtk.datamodel.interfaces.TimeValue;
 import com.fasterxml.jackson.databind.exc.InvalidDefinitionException;
 
 import com.google.refine.browsing.Engine;
+import com.google.refine.browsing.EngineConfig;
 import com.google.refine.model.Project;
 import com.google.refine.tests.RefineTest;
 import com.google.refine.util.ParsingUtilities;
@@ -149,12 +150,21 @@ public class WikibaseSchemaTest extends RefineTest {
         JSONObject serialized = TestingData.jsonFromFile("data/schema/inception.json");
         WikibaseSchema schema = WikibaseSchema.reconstruct(serialized);
         Engine engine = new Engine(project);
-        JSONObject engineConfig = new JSONObject("{\n" + "      \"mode\": \"row-based\",\n" + "      \"facets\": [\n"
+        EngineConfig engineConfig = EngineConfig.reconstruct(new JSONObject("{\n"
-                + "        {\n" + "          \"mode\": \"text\",\n" + "          \"invert\": false,\n"
+                + "      \"mode\": \"row-based\",\n" 
-                + "          \"caseSensitive\": false,\n" + "          \"query\": \"www\",\n"
+                + "      \"facets\": [\n"
-                + "          \"name\": \"reference\",\n" + "          \"type\": \"text\",\n"
+                + "        {\n"
-                + "          \"columnName\": \"reference\"\n" + "        }\n" + "      ]\n" + "    }");
+                + "          \"mode\": \"text\",\n"
-        engine.initializeFromJSON(engineConfig);
+                + "          \"invert\": false,\n"
+                + "          \"caseSensitive\": false,\n"
+                + "          \"query\": \"www\",\n"
+                + "          \"name\": \"reference\",\n"
+                + "          \"type\": \"text\",\n"
+                + "          \"columnName\": \"reference\"\n"
+                + "        }\n"
+                + "      ]\n"
+                + "    }"));
+        engine.initializeFromConfig(engineConfig);
         List<ItemUpdate> updates = schema.evaluate(project, engine);
         List<ItemUpdate> expected = new ArrayList<>();
         ItemUpdate update1 = new ItemUpdateBuilder(qid1).addStatement(statement1).build();

main/src/com/google/refine/browsing/Engine.java

@@ -33,22 +33,18 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 package com.google.refine.browsing;
 
+import java.util.Collections;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Properties;
+import java.util.stream.Collectors;
 
-import org.json.JSONArray;
 import org.json.JSONException;
 import org.json.JSONObject;
 import org.json.JSONWriter;
 
 import com.google.refine.Jsonizable;
 import com.google.refine.browsing.facets.Facet;
-import com.google.refine.browsing.facets.ListFacet;
-import com.google.refine.browsing.facets.RangeFacet;
-import com.google.refine.browsing.facets.ScatterplotFacet;
-import com.google.refine.browsing.facets.TextSearchFacet;
-import com.google.refine.browsing.facets.TimeRangeFacet;
 import com.google.refine.browsing.util.ConjunctiveFilteredRecords;
 import com.google.refine.browsing.util.ConjunctiveFilteredRows;
 import com.google.refine.browsing.util.FilteredRecordsAsFilteredRows;
@@ -71,7 +67,7 @@ public class Engine implements Jsonizable {
 
     protected Project _project;
     protected List<Facet> _facets = new LinkedList<Facet>();
-    protected Mode _mode = Mode.RowBased;
+    protected EngineConfig _config = new EngineConfig(Collections.emptyList(), Mode.RowBased);
 
     static public String modeToString(Mode mode) {
         return mode == Mode.RowBased ? MODE_ROW_BASED : MODE_RECORD_BASED;
@@ -85,10 +81,10 @@ public class Engine implements Jsonizable {
     }
 
     public Mode getMode() {
-        return _mode;
+        return _config.getMode();
     }
     public void setMode(Mode mode) {
-        _mode = mode;
+        _config = new EngineConfig(_config.getFacetConfigs(), mode);
     }
 
     public FilteredRows getAllRows() {
@@ -117,9 +113,9 @@ public class Engine implements Jsonizable {
     }
 
     public FilteredRows getFilteredRows(Facet except) {
-        if (_mode == Mode.RecordBased) {
+        if (_config.getMode().equals(Mode.RecordBased)) {
             return new FilteredRecordsAsFilteredRows(getFilteredRecords(except));
-        } else if (_mode == Mode.RowBased) {
+        } else if (_config.getMode().equals(Mode.RowBased)) {
             ConjunctiveFilteredRows cfr = new ConjunctiveFilteredRows();
             for (Facet facet : _facets) {
                 if (facet != except) {
@@ -157,7 +153,7 @@ public class Engine implements Jsonizable {
     }
 
     public FilteredRecords getFilteredRecords(Facet except) {
-        if (_mode == Mode.RecordBased) {
+        if (_config.getMode().equals(Mode.RecordBased)) {
             ConjunctiveFilteredRecords cfr = new ConjunctiveFilteredRecords();
             for (Facet facet : _facets) {
                 if (facet != except) {
@@ -172,57 +168,27 @@ public class Engine implements Jsonizable {
         throw new InternalError("This method should not be called when the engine is not in record mode.");
     }
 
+    @Deprecated
     public void initializeFromJSON(JSONObject o) throws JSONException {
-        if (o == null) {
+        EngineConfig config = EngineConfig.reconstruct(o);
-            return;
+        initializeFromConfig(config);
     }
     
-        if (o.has("facets") && !o.isNull("facets")) {
+    public void initializeFromConfig(EngineConfig config) {
-            JSONArray a = o.getJSONArray("facets");
+        _config = config;
-            int length = a.length();
+        _facets = config.getFacetConfigs().stream()
-
+                .map(c -> c.apply(_project))
-            for (int i = 0; i < length; i++) {
+                .collect(Collectors.toList());
-                JSONObject fo = a.getJSONObject(i);
-                String type = fo.has("type") ? fo.getString("type") : "list";
-
-                Facet facet = null;
-                if ("list".equals(type)) {
-                    facet = new ListFacet();
-                } else if ("range".equals(type)) {
-                    facet = new RangeFacet();
-                } else if ("timerange".equals(type)) {
-                    facet = new TimeRangeFacet();
-                } else if ("scatterplot".equals(type)) {
-                    facet = new ScatterplotFacet();
-                } else if ("text".equals(type)) {
-                    facet = new TextSearchFacet();
-                }
-
-                if (facet != null) {
-                    facet.initializeFromJSON(_project, fo);
-                    _facets.add(facet);
-                }
-            }
-        }
-
-        // for backward compatibility
-        if (o.has(INCLUDE_DEPENDENT) && !o.isNull(INCLUDE_DEPENDENT)) {
-            _mode = o.getBoolean(INCLUDE_DEPENDENT) ? Mode.RecordBased : Mode.RowBased;
-        }
-
-        if (o.has(MODE) && !o.isNull(MODE)) {
-            _mode = MODE_ROW_BASED.equals(o.getString(MODE)) ? Mode.RowBased : Mode.RecordBased;
-        }
     }
 
     public void computeFacets() throws JSONException {
-        if (_mode == Mode.RowBased) {
+        if (_config.getMode().equals(Mode.RowBased)) {
             for (Facet facet : _facets) {
                 FilteredRows filteredRows = getFilteredRows(facet);
 
                 facet.computeChoices(_project, filteredRows);
             }
-        } else if (_mode == Mode.RecordBased) {
+        } else if (_config.getMode().equals(Mode.RecordBased)) {
             for (Facet facet : _facets) {
                 FilteredRecords filteredRecords = getFilteredRecords(facet);
 
@@ -244,7 +210,7 @@ public class Engine implements Jsonizable {
             facet.write(writer, options);
         }
         writer.endArray();
-        writer.key(MODE); writer.value(_mode == Mode.RowBased ? MODE_ROW_BASED : MODE_RECORD_BASED);
+        writer.key(MODE); writer.value(_config.getMode().equals(Mode.RowBased) ? MODE_ROW_BASED : MODE_RECORD_BASED);
         writer.endObject();
     }
 }

main/src/com/google/refine/browsing/EngineConfig.java

@@ -0,0 +1,102 @@
+package com.google.refine.browsing;
+
+import java.util.Collections;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Properties;
+
+import org.json.JSONArray;
+import org.json.JSONException;
+import org.json.JSONObject;
+import org.json.JSONWriter;
+
+import com.google.refine.Jsonizable;
+import com.google.refine.browsing.Engine.Mode;
+import com.google.refine.browsing.facets.FacetConfig;
+import com.google.refine.browsing.facets.ListFacet.ListFacetConfig;
+import com.google.refine.browsing.facets.RangeFacet.RangeFacetConfig;
+import com.google.refine.browsing.facets.ScatterplotFacet.ScatterplotFacetConfig;
+import com.google.refine.browsing.facets.TextSearchFacet.TextSearchFacetConfig;
+import com.google.refine.browsing.facets.TimeRangeFacet.TimeRangeFacetConfig;
+
+
+public class EngineConfig implements Jsonizable {
+    
+    protected final List<FacetConfig> _facets;
+    protected final Mode _mode;
+    
+    public EngineConfig(List<FacetConfig> facets, Mode mode) {
+        _facets = facets;
+        _mode = mode;
+    }
+    
+    public Mode getMode() {
+        return _mode;
+    }
+    
+    public List<FacetConfig> getFacetConfigs() {
+        return _facets;
+    }
+    
+    public static EngineConfig reconstruct(JSONObject o) {
+        if (o == null) {
+            return new EngineConfig(Collections.emptyList(), Mode.RowBased);
+        }
+
+        List<FacetConfig> facets = new LinkedList<>();
+        if (o.has("facets") && !o.isNull("facets")) {
+            JSONArray a = o.getJSONArray("facets");
+            int length = a.length();
+
+            for (int i = 0; i < length; i++) {
+                JSONObject fo = a.getJSONObject(i);
+                String type = fo.has("type") ? fo.getString("type") : "list";
+
+                FacetConfig facet = null;
+                if ("list".equals(type)) {
+                    facet = new ListFacetConfig();
+                } else if ("range".equals(type)) {
+                    facet = new RangeFacetConfig();
+                } else if ("timerange".equals(type)) {
+                    facet = new TimeRangeFacetConfig();
+                } else if ("scatterplot".equals(type)) {
+                    facet = new ScatterplotFacetConfig();
+                } else if ("text".equals(type)) {
+                    facet = new TextSearchFacetConfig();
+                }
+
+                if (facet != null) {
+                    facet.initializeFromJSON(fo);
+                    facets.add(facet);
+                }
+            }
+        }
+
+        Mode mode = Mode.RowBased;
+        // for backward compatibility
+        if (o.has(Engine.INCLUDE_DEPENDENT) && !o.isNull(Engine.INCLUDE_DEPENDENT)) {
+            mode = o.getBoolean(Engine.INCLUDE_DEPENDENT) ? Mode.RecordBased : Mode.RowBased;
+        }
+
+        if (o.has(Engine.MODE) && !o.isNull(Engine.MODE)) {
+            mode = Engine.MODE_ROW_BASED.equals(o.getString(Engine.MODE)) ? Mode.RowBased : Mode.RecordBased;
+        }
+        
+        return new EngineConfig(facets, mode);
+    }
+
+    @Override
+    public void write(JSONWriter writer, Properties options)
+            throws JSONException {
+        writer.object();
+        writer.key("facets");
+        writer.array();
+        for (FacetConfig facet : _facets) {
+            facet.write(writer, options);
+        }
+        writer.endArray();
+        writer.key(Engine.MODE); writer.value(_mode == Mode.RowBased ? Engine.MODE_ROW_BASED : Engine.MODE_RECORD_BASED);
+        writer.endObject();
+    }
+
+}

main/src/com/google/refine/browsing/facets/Facet.java

@@ -33,9 +33,6 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 package com.google.refine.browsing.facets;
 
-import org.json.JSONException;
-import org.json.JSONObject;
-
 import com.google.refine.Jsonizable;
 import com.google.refine.browsing.FilteredRecords;
 import com.google.refine.browsing.FilteredRows;
@@ -54,6 +51,4 @@ public interface Facet extends Jsonizable {
     public void computeChoices(Project project, FilteredRows filteredRows);
     
     public void computeChoices(Project project, FilteredRecords filteredRecords);
-    
-    public void initializeFromJSON(Project project, JSONObject o) throws JSONException;
 }

main/src/com/google/refine/browsing/facets/FacetConfig.java

@@ -0,0 +1,31 @@
+package com.google.refine.browsing.facets;
+
+import org.json.JSONObject;
+
+import com.google.refine.Jsonizable;
+import com.google.refine.model.Project;
+
+
+/**
+ * Represents the configuration of a facet, as stored
+ * in the engine configuration and in the JSON serialization
+ * of operations. It does not contain the actual values displayed by
+ * the facet.
+ * 
+ * @author antonin
+ *
+ */
+public interface FacetConfig extends Jsonizable {
+    /**
+     * Reads the facet configuration from a JSON object (will be removed once we migrate to Jackson)
+     * @param fo
+     */
+    public void initializeFromJSON(JSONObject fo);
+    
+    /**
+     * Instantiates the given facet on a particular project.
+     * @param project
+     * @return a computed facet on the given project.
+     */
+    public Facet apply(Project project);
+}

main/src/com/google/refine/browsing/facets/ListFacet.java

@@ -63,18 +63,80 @@ public class ListFacet implements Facet {
     /*
      * Configuration
      */
-    protected String     _name;
+    public static class ListFacetConfig implements FacetConfig {
-    protected String     _expression;
+        public String     name;
-    protected String     _columnName;
+        public String     expression;
-    protected boolean    _invert;
+        public String     columnName;
+        public boolean    invert;
         
         // If true, then facet won't show the blank and error choices
-    protected boolean _omitBlank;
+        public boolean omitBlank;
-    protected boolean _omitError;
+        public boolean omitError;
         
-    protected List<NominalFacetChoice> _selection = new LinkedList<NominalFacetChoice>();
+        public List<DecoratedValue> selection = new LinkedList<>();
-    protected boolean _selectBlank;
+        public boolean selectBlank;
-    protected boolean _selectError;
+        public boolean selectError;
+
+        @Override
+        public void write(JSONWriter writer, Properties options)
+                throws JSONException {
+            writer.object();
+            writer.key("type"); writer.value("list");
+            writer.key("name"); writer.value(name);
+            writer.key("expression"); writer.value(expression);
+            writer.key("columnName"); writer.value(columnName);
+            writer.key("invert"); writer.value(invert);
+            writer.key("selection"); writer.array();
+            for (DecoratedValue choice : selection) {
+                writer.object();
+                writer.key("v");
+                choice.write(writer, options);
+                writer.endObject();
+            }
+            writer.endArray();
+            writer.key("omitBlank"); writer.value(omitBlank);
+            writer.key("selectBlank"); writer.value(selectBlank);
+            writer.key("omitError"); writer.value(omitError);
+            writer.key("selectError"); writer.value(selectError);
+            writer.endObject();
+        }
+        
+        @Override
+        public void initializeFromJSON(JSONObject o) {
+            name = o.getString("name");
+            expression = o.getString("expression");
+            columnName = o.getString("columnName");
+            invert = o.has("invert") && o.getBoolean("invert");
+                      
+            JSONArray a = o.getJSONArray("selection");
+            int length = a.length();
+            
+            for (int i = 0; i < length; i++) {
+                JSONObject oc = a.getJSONObject(i);
+                JSONObject ocv = oc.getJSONObject("v");
+                
+                DecoratedValue decoratedValue = new DecoratedValue(
+                    ocv.get("v"), ocv.getString("l"));
+                
+                selection.add(decoratedValue);
+            }
+            
+            omitBlank = JSONUtilities.getBoolean(o, "omitBlank", false);
+            omitError = JSONUtilities.getBoolean(o, "omitError", false);
+            
+            selectBlank = JSONUtilities.getBoolean(o, "selectBlank", false);
+            selectError = JSONUtilities.getBoolean(o, "selectError", false);
+        }
+        
+        @Override
+        public Facet apply(Project project) {
+            ListFacet facet = new ListFacet();
+            facet.initializeFromConfig(this, project);
+            return facet;
+        }
+    }
+    
+    ListFacetConfig _config = new ListFacetConfig();
     
     /*
      * Derived configuration
@@ -98,10 +160,10 @@ public class ListFacet implements Facet {
             throws JSONException {
         
         writer.object();
-        writer.key("name"); writer.value(_name);
+        writer.key("name"); writer.value(_config.name);
-        writer.key("expression"); writer.value(_expression);
+        writer.key("expression"); writer.value(_config.expression);
-        writer.key("columnName"); writer.value(_columnName);
+        writer.key("columnName"); writer.value(_config.columnName);
-        writer.key("invert"); writer.value(_invert);
+        writer.key("invert"); writer.value(_config.invert);
         
         if (_errorMessage != null) {
             writer.key("error"); writer.value(_errorMessage);
@@ -115,17 +177,17 @@ public class ListFacet implements Facet {
             }
             writer.endArray();
             
-            if (!_omitBlank && (_selectBlank || _blankCount > 0)) {
+            if (!_config.omitBlank && (_config.selectBlank || _blankCount > 0)) {
                 writer.key("blankChoice");
                 writer.object();
-                writer.key("s"); writer.value(_selectBlank);
+                writer.key("s"); writer.value(_config.selectBlank);
                 writer.key("c"); writer.value(_blankCount);
                 writer.endObject();
             }
-            if (!_omitError && (_selectError || _errorCount > 0)) {
+            if (!_config.omitError && (_config.selectError || _errorCount > 0)) {
                 writer.key("errorChoice");
                 writer.object();
-                writer.key("s"); writer.value(_selectError);
+                writer.key("s"); writer.value(_config.selectError);
                 writer.key("c"); writer.value(_errorCount);
                 writer.endObject();
             }
@@ -151,53 +213,24 @@ public class ListFacet implements Facet {
         return 2000;
     }
         
-    @Override
+    public void initializeFromConfig(ListFacetConfig config, Project project) {
-    public void initializeFromJSON(Project project, JSONObject o) throws JSONException {
+        _config = config;
-        _name = o.getString("name");
+        if (_config.columnName.length() > 0) {
-        _expression = o.getString("expression");
+            Column column = project.columnModel.getColumnByName(_config.columnName);
-        _columnName = o.getString("columnName");
-        _invert = o.has("invert") && o.getBoolean("invert");
-        
-        if (_columnName.length() > 0) {
-            Column column = project.columnModel.getColumnByName(_columnName);
             if (column != null) {
                 _cellIndex = column.getCellIndex();
             } else {
-                _errorMessage = "No column named " + _columnName;
+                _errorMessage = "No column named " + _config.columnName;
             }
         } else {
             _cellIndex = -1;
         }
         
         try {
-            _eval = MetaParser.parse(_expression);
+            _eval = MetaParser.parse(_config.expression);
         } catch (ParsingException e) {
             _errorMessage = e.getMessage();
         }
-        
-        _selection.clear();
-        
-        JSONArray a = o.getJSONArray("selection");
-        int length = a.length();
-        
-        for (int i = 0; i < length; i++) {
-            JSONObject oc = a.getJSONObject(i);
-            JSONObject ocv = oc.getJSONObject("v");
-            
-            DecoratedValue decoratedValue = new DecoratedValue(
-                ocv.get("v"), ocv.getString("l"));
-            
-            NominalFacetChoice nominalFacetChoice = new NominalFacetChoice(decoratedValue);
-            nominalFacetChoice.selected = true;
-            
-            _selection.add(nominalFacetChoice);
-        }
-        
-        _omitBlank = JSONUtilities.getBoolean(o, "omitBlank", false);
-        _omitError = JSONUtilities.getBoolean(o, "omitError", false);
-        
-        _selectBlank = JSONUtilities.getBoolean(o, "selectBlank", false);
-        _selectError = JSONUtilities.getBoolean(o, "selectError", false);
     }
 
     @Override
@@ -205,23 +238,23 @@ public class ListFacet implements Facet {
         return 
             _eval == null || 
             _errorMessage != null ||
-            (_selection.size() == 0 && !_selectBlank && !_selectError) ? 
+            (_config.selection.size() == 0 && !_config.selectBlank && !_config.selectError) ? 
                 null :
                 new ExpressionEqualRowFilter(
                     _eval, 
-                    _columnName,
+                    _config.columnName,
                     _cellIndex, 
                     createMatches(), 
-                    _selectBlank, 
+                    _config.selectBlank, 
-                    _selectError,
+                    _config.selectError,
-                    _invert);
+                    _config.invert);
     }
     
     @Override
     public RecordFilter getRecordFilter(Project project) {
         RowFilter rowFilter = getRowFilter(project);
         return rowFilter == null ? null :
-            (_invert ?
+            (_config.invert ?
                     new AllRowsRecordFilter(rowFilter) :
                         new AnyRowRecordFilter(rowFilter));
     }
@@ -230,7 +263,7 @@ public class ListFacet implements Facet {
     public void computeChoices(Project project, FilteredRows filteredRows) {
         if (_eval != null && _errorMessage == null) {
             ExpressionNominalValueGrouper grouper = 
-                new ExpressionNominalValueGrouper(_eval, _columnName, _cellIndex);
+                new ExpressionNominalValueGrouper(_eval, _config.columnName, _cellIndex);
             
             filteredRows.accept(project, grouper);
             
@@ -242,7 +275,7 @@ public class ListFacet implements Facet {
     public void computeChoices(Project project, FilteredRecords filteredRecords) {
         if (_eval != null && _errorMessage == null) {
             ExpressionNominalValueGrouper grouper = 
-                new ExpressionNominalValueGrouper(_eval, _columnName, _cellIndex);
+                new ExpressionNominalValueGrouper(_eval, _config.columnName, _cellIndex);
             
             filteredRecords.accept(project, grouper);
             
@@ -254,8 +287,8 @@ public class ListFacet implements Facet {
         _choices.clear();
         _choices.addAll(grouper.choices.values());
         
-        for (NominalFacetChoice choice : _selection) {
+        for (DecoratedValue decoratedValue : _config.selection) {
-            String valueString = choice.decoratedValue.value.toString();
+            String valueString = decoratedValue.value.toString();
             
             if (grouper.choices.containsKey(valueString)) {
                 grouper.choices.get(valueString).selected = true;
@@ -270,6 +303,7 @@ public class ListFacet implements Facet {
                  *  won't be able to detect the "bicycle" choice, so we need to inject
                  *  that choice into the choice list ourselves.
                  */
+                NominalFacetChoice choice = new NominalFacetChoice(decoratedValue);
                 choice.count = 0;
                 _choices.add(choice);
             }
@@ -280,9 +314,9 @@ public class ListFacet implements Facet {
     }
     
     protected Object[] createMatches() {
-        Object[] a = new Object[_selection.size()];
+        Object[] a = new Object[_config.selection.size()];
         for (int i = 0; i < a.length; i++) {
-            a[i] = _selection.get(i).decoratedValue.value;
+            a[i] = _config.selection.get(i).value;
         }
         return a;
     }

main/src/com/google/refine/browsing/facets/RangeFacet.java

@@ -62,6 +62,7 @@ public class RangeFacet implements Facet {
     /*
      * Configuration, from the client side
      */
+    public static class RangeFacetConfig implements FacetConfig {
         protected String     _name;       // name of facet
         protected String     _expression; // expression to compute numeric value(s) per row
         protected String     _columnName; // column to base expression on, if any
@@ -74,14 +75,62 @@ public class RangeFacet implements Facet {
         protected boolean   _selectBlank;
         protected boolean   _selectError;
         
+        protected boolean    _selected; // false if we're certain that all rows will match
+                        // and there isn't any filtering to do
+        
+        @Override
+        public void write(JSONWriter writer, Properties options)
+                throws JSONException {
+            writer.object();
+            writer.key("type"); writer.value("range");
+            writer.key("name"); writer.value(_name);
+            writer.key("expression"); writer.value(_expression);
+            writer.key("columnName"); writer.value(_columnName);
+            writer.key(FROM); writer.value(_from);
+            writer.key(TO); writer.value(_to);
+            writer.key("selectNumeric"); writer.value(_selectNumeric);
+            writer.key("selectNonNumeric"); writer.value(_selectNonNumeric);
+            writer.key("selectError"); writer.value(_selectError);
+            writer.key("selectBlank"); writer.value(_selectBlank);
+            writer.endObject();
+            
+        }
+        
+        @Override
+        public void initializeFromJSON(JSONObject o) {
+            _name = o.getString("name");
+            _expression = o.getString("expression");
+            _columnName = o.getString("columnName");
+            if (o.has(FROM) || o.has(TO)) {
+                _from = o.has(FROM) ? o.getDouble(FROM) : 0;
+                _to = o.has(TO) ? o.getDouble(TO) : 0;
+                _selected = true;
+            }
+            _selectNumeric = JSONUtilities.getBoolean(o, "selectNumeric", true);
+            _selectNonNumeric = JSONUtilities.getBoolean(o, "selectNonNumeric", true);
+            _selectBlank = JSONUtilities.getBoolean(o, "selectBlank", true);
+            _selectError = JSONUtilities.getBoolean(o, "selectError", true);
+            
+            if (!_selectNumeric || !_selectNonNumeric || !_selectBlank || !_selectError) {
+                _selected = true;
+            }
+        }
+        
+        @Override
+        public RangeFacet apply(Project project) {
+            RangeFacet facet = new RangeFacet();
+            facet.initializeFromConfig(this, project);
+            return facet;
+        }
+    }
+    RangeFacetConfig _config = new RangeFacetConfig();
+    
     /*
      * Derived configuration data
      */
     protected int        _cellIndex;
     protected Evaluable  _eval;
     protected String     _errorMessage;
-    protected boolean    _selected; // false if we're certain that all rows will match
-                                    // and there isn't any filtering to do
     
     /*
      * Computed data, to return to the client side
@@ -115,9 +164,9 @@ public class RangeFacet implements Facet {
             throws JSONException {
         
         writer.object();
-        writer.key("name"); writer.value(_name);
+        writer.key("name"); writer.value(_config._name);
-        writer.key("expression"); writer.value(_expression);
+        writer.key("expression"); writer.value(_config._expression);
-        writer.key("columnName"); writer.value(_columnName);
+        writer.key("columnName"); writer.value(_config._columnName);
         
         if (_errorMessage != null) {
             writer.key("error"); writer.value(_errorMessage);
@@ -139,8 +188,8 @@ public class RangeFacet implements Facet {
                 }
                 writer.endArray();
                 
-                writer.key(FROM); writer.value(_from);
+                writer.key(FROM); writer.value(_config._from);
-                writer.key(TO); writer.value(_to);
+                writer.key(TO); writer.value(_config._to);
             } else {
                 writer.key("error"); writer.value("No numeric value present.");
             }
@@ -158,54 +207,36 @@ public class RangeFacet implements Facet {
         writer.endObject();
     }
     
-    @Override
+    public void initializeFromConfig(RangeFacetConfig config, Project project) {
-    public void initializeFromJSON(Project project, JSONObject o) throws JSONException {
+        _config = config;
-        _name = o.getString("name");
-        _expression = o.getString("expression");
-        _columnName = o.getString("columnName");
         
-        if (_columnName.length() > 0) {
+        if (_config._columnName.length() > 0) {
-            Column column = project.columnModel.getColumnByName(_columnName);
+            Column column = project.columnModel.getColumnByName(_config._columnName);
             if (column != null) {
                 _cellIndex = column.getCellIndex();
             } else {
-                _errorMessage = "No column named " + _columnName;
+                _errorMessage = "No column named " + _config._columnName;
             }
         } else {
             _cellIndex = -1;
         }
         
         try {
-            _eval = MetaParser.parse(_expression);
+            _eval = MetaParser.parse(_config._expression);
         } catch (ParsingException e) {
             _errorMessage = e.getMessage();
         }
-        
-        if (o.has(FROM) || o.has(TO)) {
-            _from = o.has(FROM) ? o.getDouble(FROM) : _min;
-            _to = o.has(TO) ? o.getDouble(TO) : _max;
-            _selected = true;
-        }
-        
-        _selectNumeric = JSONUtilities.getBoolean(o, "selectNumeric", true);
-        _selectNonNumeric = JSONUtilities.getBoolean(o, "selectNonNumeric", true);
-        _selectBlank = JSONUtilities.getBoolean(o, "selectBlank", true);
-        _selectError = JSONUtilities.getBoolean(o, "selectError", true);
-        
-        if (!_selectNumeric || !_selectNonNumeric || !_selectBlank || !_selectError) {
-            _selected = true;
-        }
     }
 
     @Override
     public RowFilter getRowFilter(Project project) {
-        if (_eval != null && _errorMessage == null && _selected) {
+        if (_eval != null && _errorMessage == null && _config._selected) {
             return new ExpressionNumberComparisonRowFilter(
-                    getRowEvaluable(project), _selectNumeric, _selectNonNumeric, _selectBlank, _selectError) {
+                    getRowEvaluable(project), _config._selectNumeric, _config._selectNonNumeric, _config._selectBlank, _config._selectError) {
 
                 @Override
                 protected boolean checkValue(double d) {
-                    return d >= _from && d < _to;
+                    return d >= _config._from && d < _config._to;
                 };
             };
         } else {
@@ -225,7 +256,7 @@ public class RangeFacet implements Facet {
             RowEvaluable rowEvaluable = getRowEvaluable(project);
             
             Column column = project.columnModel.getColumnByCellIndex(_cellIndex);
-            String key = "numeric-bin:row-based:" + _expression;
+            String key = "numeric-bin:row-based:" + _config._expression;
             NumericBinIndex index = (NumericBinIndex) column.getPrecompute(key);
             if (index == null) {
                 index = new NumericBinRowIndex(project, rowEvaluable);
@@ -248,7 +279,7 @@ public class RangeFacet implements Facet {
             RowEvaluable rowEvaluable = getRowEvaluable(project);
             
             Column column = project.columnModel.getColumnByCellIndex(_cellIndex);
-            String key = "numeric-bin:record-based:" + _expression;
+            String key = "numeric-bin:record-based:" + _config._expression;
             NumericBinIndex index = (NumericBinIndex) column.getPrecompute(key);
             if (index == null) {
                 index = new NumericBinRecordIndex(project, rowEvaluable);
@@ -267,7 +298,7 @@ public class RangeFacet implements Facet {
     }
     
     protected RowEvaluable getRowEvaluable(Project project) {
-        return new ExpressionBasedRowEvaluable(_columnName, _cellIndex, _eval);
+        return new ExpressionBasedRowEvaluable(_config._columnName, _cellIndex, _eval);
     }
     
     protected void retrieveDataFromBaseBinIndex(NumericBinIndex index) {
@@ -281,12 +312,12 @@ public class RangeFacet implements Facet {
         _baseBlankCount = index.getBlankRowCount();
         _baseErrorCount = index.getErrorRowCount();
         
-        if (_selected) {
+        if (_config._selected) {
-            _from = Math.max(_from, _min);
+            _config._from = Math.max(_config._from, _min);
-            _to = Math.min(_to, _max);
+            _config._to = Math.min(_config._to, _max);
         } else {
-            _from = _min;
+            _config._from = _min;
-            _to = _max;
+            _config._to = _max;
         }
     }
     

main/src/com/google/refine/browsing/facets/ScatterplotFacet.java

@@ -79,6 +79,7 @@ public class ScatterplotFacet implements Facet {
     /*
      * Configuration, from the client side
      */
+    public static class ScatterplotFacetConfig implements FacetConfig {
         protected String name; // name of facet
     
         protected String expression_x; // expression to compute the x numeric value(s) per row
@@ -89,13 +90,12 @@ public class ScatterplotFacet implements Facet {
         protected int size;
         protected int dim_x;
         protected int dim_y;
+        protected String rotation_str;
         protected int rotation;
     
         protected double l;
         protected double dot;
     
-    protected String image;
-    
         protected String color_str;
         protected Color color;
         
@@ -104,6 +104,98 @@ public class ScatterplotFacet implements Facet {
         protected double from_y; // the numeric selection for the y axis, from 0 to 1
         protected double to_y;
         
+        protected boolean selected; // false if we're certain that all rows will match
+        // and there isn't any filtering to do
+        
+        @Override
+        public void write(JSONWriter writer, Properties options)
+                throws JSONException {
+            writer.object();
+            
+            writer.key("type"); writer.value("scatterplot");
+            writer.key(NAME); writer.value(name);
+            writer.key(X_COLUMN_NAME); writer.value(columnName_x);
+            writer.key(X_EXPRESSION); writer.value(expression_x);
+            writer.key(Y_COLUMN_NAME); writer.value(columnName_y);
+            writer.key(Y_EXPRESSION); writer.value(expression_y);
+            writer.key(SIZE); writer.value(size);
+            writer.key(DOT); writer.value(dot);
+            if(!rotation_str.isEmpty()) {
+                writer.key(ROTATION); writer.value(rotation_str);
+            }
+            writer.key(DIM_X); writer.value(dim_x == LIN ? "lin" : "log");
+            writer.key(DIM_Y); writer.value(dim_y == LIN ? "lin" : "log");
+            if(!"000000".equals(color_str)) {
+                writer.key(COLOR); writer.value(color_str);
+            }
+            writer.key(FROM_X); writer.value(from_x);
+            writer.key(TO_X); writer.value(to_x);
+            writer.key(FROM_Y); writer.value(from_y);
+            writer.key(TO_Y); writer.value(to_y);
+            
+            writer.endObject();
+            
+        }
+        
+        @Override
+        public ScatterplotFacet apply(Project project) {
+            ScatterplotFacet facet = new ScatterplotFacet();
+            facet.initializeFromConfig(this, project);
+            return facet;
+        }
+        
+        @Override
+        public void initializeFromJSON(JSONObject o) {
+            name = o.getString(NAME);
+            l = size = (o.has(SIZE)) ? o.getInt(SIZE) : 100;
+            dot = (o.has(DOT)) ? o.getInt(DOT) : 0.5d;
+            
+            dim_x = (o.has(DIM_X)) ? getAxisDim(o.getString(DIM_X)) : LIN;
+            if (o.has(FROM_X) && o.has(TO_X)) {
+                from_x = o.getDouble(FROM_X);
+                to_x = o.getDouble(TO_X);
+                selected = true;
+            } else {
+                from_x = 0;
+                to_x = 1;
+            }
+            
+            dim_y = (o.has(DIM_Y)) ? getAxisDim(o.getString(DIM_Y)) : LIN;
+            if (o.has(FROM_Y) && o.has(TO_Y)) {
+                from_y = o.getDouble(FROM_Y);
+                to_y = o.getDouble(TO_Y);
+                selected = true;
+            } else {
+                from_y = 0;
+                to_y = 1;
+            }
+            
+            rotation_str = (o.has(ROTATION) ? o.getString(ROTATION) : "");
+            rotation = getRotation(rotation_str);
+            
+            color_str = (o.has(COLOR)) ? o.getString(COLOR) : "000000";
+            color = new Color(Integer.parseInt(color_str,16));
+            
+            columnName_x = o.getString(X_COLUMN_NAME);
+            expression_x = o.getString(X_EXPRESSION);
+            
+            columnName_y = o.getString(Y_COLUMN_NAME);
+            expression_y = o.getString(Y_EXPRESSION);
+        }
+        
+        public static int getRotation(String rotation) {
+            rotation = rotation.toLowerCase();
+            if ("cw".equals(rotation) || "right".equals(rotation)) {
+                return ScatterplotFacet.ROTATE_CW;
+            } else if ("ccw".equals(rotation) || "left".equals(rotation)) {
+                return ScatterplotFacet.ROTATE_CCW;
+            } else {
+                return NO_ROTATION;
+            }
+        }
+    }
+    ScatterplotFacetConfig config;
+
     /*
      * Derived configuration data
      */
@@ -120,8 +212,8 @@ public class ScatterplotFacet implements Facet {
     protected double max_y;
     protected AffineTransform t;
     
-    protected boolean selected; // false if we're certain that all rows will match
+    protected String image;
-                                // and there isn't any filtering to do
+    
         
     public static final String NAME = "name";
     public static final String IMAGE = "image";
@@ -168,17 +260,17 @@ public class ScatterplotFacet implements Facet {
         
         writer.object();
         
-        writer.key(NAME); writer.value(name);
+        writer.key(NAME); writer.value(config.name);
-        writer.key(X_COLUMN_NAME); writer.value(columnName_x);
+        writer.key(X_COLUMN_NAME); writer.value(config.columnName_x);
-        writer.key(X_EXPRESSION); writer.value(expression_x);
+        writer.key(X_EXPRESSION); writer.value(config.expression_x);
-        writer.key(Y_COLUMN_NAME); writer.value(columnName_y);
+        writer.key(Y_COLUMN_NAME); writer.value(config.columnName_y);
-        writer.key(Y_EXPRESSION); writer.value(expression_y);
+        writer.key(Y_EXPRESSION); writer.value(config.expression_y);
-        writer.key(SIZE); writer.value(size);
+        writer.key(SIZE); writer.value(config.size);
-        writer.key(DOT); writer.value(dot);
+        writer.key(DOT); writer.value(config.dot);
-        writer.key(ROTATION); writer.value(rotation);
+        writer.key(ROTATION); writer.value(config.rotation);
-        writer.key(DIM_X); writer.value(dim_x);
+        writer.key(DIM_X); writer.value(config.dim_x);
-        writer.key(DIM_Y); writer.value(dim_y);
+        writer.key(DIM_Y); writer.value(config.dim_y);
-        writer.key(COLOR); writer.value(color_str);
+        writer.key(COLOR); writer.value(config.color_str);
 
         if (IMAGE_URI) {
             writer.key(IMAGE); writer.value(image);
@@ -188,8 +280,8 @@ public class ScatterplotFacet implements Facet {
             writer.key(ERROR_X); writer.value(errorMessage_x);
         } else {
             if (!Double.isInfinite(min_x) && !Double.isInfinite(max_x)) {
-                writer.key(FROM_X); writer.value(from_x);
+                writer.key(FROM_X); writer.value(config.from_x);
-                writer.key(TO_X); writer.value(to_x);
+                writer.key(TO_X); writer.value(config.to_x);
             }
         }
             
@@ -197,90 +289,57 @@ public class ScatterplotFacet implements Facet {
             writer.key(ERROR_Y); writer.value(errorMessage_y);
         } else {
             if (!Double.isInfinite(min_y) && !Double.isInfinite(max_y)) {
-                writer.key(FROM_Y); writer.value(from_y);
+                writer.key(FROM_Y); writer.value(config.from_y);
-                writer.key(TO_Y); writer.value(to_y);
+                writer.key(TO_Y); writer.value(config.to_y);
             }
         }
         
         writer.endObject();
     }
      
-    @Override
+    public void initializeFromConfig(ScatterplotFacetConfig configuration, Project project) {
-    public void initializeFromJSON(Project project, JSONObject o) throws JSONException {
+        config = configuration;
-        name = o.getString(NAME);
-        l = size = (o.has(SIZE)) ? o.getInt(SIZE) : 100;
-        dot = (o.has(DOT)) ? o.getInt(DOT) : 0.5d;
         
-        dim_x = (o.has(DIM_X)) ? getAxisDim(o.getString(DIM_X)) : LIN;
+        t = createRotationMatrix(config.rotation, config.l);
-        if (o.has(FROM_X) && o.has(TO_X)) {
-            from_x = o.getDouble(FROM_X);
-            to_x = o.getDouble(TO_X);
-            selected = true;
-        } else {
-            from_x = 0;
-            to_x = 1;
-        }
         
-        dim_y = (o.has(DIM_Y)) ? getAxisDim(o.getString(DIM_Y)) : LIN;
+        if (config.columnName_x.length() > 0) {
-        if (o.has(FROM_Y) && o.has(TO_Y)) {
+            Column x_column = project.columnModel.getColumnByName(config.columnName_x);
-            from_y = o.getDouble(FROM_Y);
-            to_y = o.getDouble(TO_Y);
-            selected = true;
-        } else {
-            from_y = 0;
-            to_y = 1;
-        }
-        
-        rotation = (o.has(ROTATION)) ? getRotation(o.getString(ROTATION)) : NO_ROTATION;
-        t = createRotationMatrix(rotation, l);
-        
-        color_str = (o.has(COLOR)) ? o.getString(COLOR) : "000000";
-        color = new Color(Integer.parseInt(color_str,16));
-        
-        columnName_x = o.getString(X_COLUMN_NAME);
-        expression_x = o.getString(X_EXPRESSION);
-        
-        if (columnName_x.length() > 0) {
-            Column x_column = project.columnModel.getColumnByName(columnName_x);
             if (x_column != null) {
                 columnIndex_x = x_column.getCellIndex();
                 
-                NumericBinIndex index_x = ScatterplotFacet.getBinIndex(project, x_column, eval_x, expression_x);
+                NumericBinIndex index_x = ScatterplotFacet.getBinIndex(project, x_column, eval_x, config.expression_x);
                 min_x = index_x.getMin();
                 max_x = index_x.getMax();
             } else {
-                errorMessage_x = "No column named " + columnName_x;
+                errorMessage_x = "No column named " + config.columnName_x;
             }
         } else {
             columnIndex_x = -1;
         }
         
         try {
-            eval_x = MetaParser.parse(expression_x);
+            eval_x = MetaParser.parse(config.expression_x);
         } catch (ParsingException e) {
             errorMessage_x = e.getMessage();
         }
         
-        columnName_y = o.getString(Y_COLUMN_NAME);
+        if (config.columnName_y.length() > 0) {
-        expression_y = o.getString(Y_EXPRESSION);
+            Column y_column = project.columnModel.getColumnByName(config.columnName_y);
-        
-        if (columnName_y.length() > 0) {
-            Column y_column = project.columnModel.getColumnByName(columnName_y);
             if (y_column != null) {
                 columnIndex_y = y_column.getCellIndex();
                 
-                NumericBinIndex index_y = ScatterplotFacet.getBinIndex(project, y_column, eval_y, expression_y);
+                NumericBinIndex index_y = ScatterplotFacet.getBinIndex(project, y_column, eval_y, config.expression_y);
                 min_y = index_y.getMin();
                 max_y = index_y.getMax();
             } else {
-                errorMessage_y = "No column named " + columnName_y;
+                errorMessage_y = "No column named " + config.columnName_y;
             }
         } else {
             columnIndex_y = -1;
         }
         
         try {
-            eval_y = MetaParser.parse(expression_y);
+            eval_y = MetaParser.parse(config.expression_y);
         } catch (ParsingException e) {
             errorMessage_y = e.getMessage();
         }
@@ -289,22 +348,22 @@ public class ScatterplotFacet implements Facet {
 
     @Override
     public RowFilter getRowFilter(Project project) {
-        if (selected && 
+        if (config.selected && 
             eval_x != null && errorMessage_x == null && 
             eval_y != null && errorMessage_y == null) 
         {
             return new DualExpressionsNumberComparisonRowFilter(
-                    eval_x, columnName_x, columnIndex_x, eval_y, columnName_y, columnIndex_y) {
+                    eval_x, config.columnName_x, columnIndex_x, eval_y, config.columnName_y, columnIndex_y) {
                 
-                double from_x_pixels = from_x * l;
+                double from_x_pixels = config.from_x * config.l;
-                double to_x_pixels = to_x * l;
+                double to_x_pixels = config.to_x * config.l;
-                double from_y_pixels = from_y * l;
+                double from_y_pixels = config.from_y * config.l;
-                double to_y_pixels = to_y * l;
+                double to_y_pixels = config.to_y * config.l;
                 
                 @Override
                 protected boolean checkValues(double x, double y) {
                     Point2D.Double p = new Point2D.Double(x,y);
-                    p = translateCoordinates(p, min_x, max_x, min_y, max_y, dim_x, dim_y, l, t);
+                    p = translateCoordinates(p, min_x, max_x, min_y, max_y, config.dim_x, config.dim_y, config.l, t);
                     return p.x >= from_x_pixels && p.x <= to_x_pixels && p.y >= from_y_pixels && p.y <= to_y_pixels;
                 };
             };
@@ -323,10 +382,10 @@ public class ScatterplotFacet implements Facet {
     public void computeChoices(Project project, FilteredRows filteredRows) {
         if (eval_x != null && eval_y != null && errorMessage_x == null && errorMessage_y == null) {
             Column column_x = project.columnModel.getColumnByCellIndex(columnIndex_x);
-            NumericBinIndex index_x = getBinIndex(project, column_x, eval_x, expression_x, "row-based");
+            NumericBinIndex index_x = getBinIndex(project, column_x, eval_x, config.expression_x, "row-based");
             
             Column column_y = project.columnModel.getColumnByCellIndex(columnIndex_y);
-            NumericBinIndex index_y = getBinIndex(project, column_y, eval_y, expression_y, "row-based");
+            NumericBinIndex index_y = getBinIndex(project, column_y, eval_y, config.expression_y, "row-based");
 
             retrieveDataFromBinIndices(index_x, index_y);
             
@@ -334,7 +393,7 @@ public class ScatterplotFacet implements Facet {
                 if (index_x.isNumeric() && index_y.isNumeric()) {
                     ScatterplotDrawingRowVisitor drawer = new ScatterplotDrawingRowVisitor(
                       columnIndex_x, columnIndex_y, min_x, max_x, min_y, max_y, 
-                      size, dim_x, dim_y, rotation, dot, color
+                      config.size, config.dim_x, config.dim_y, config.rotation, config.dot, config.color
                     );
                     filteredRows.accept(project, drawer);
                  
@@ -354,10 +413,10 @@ public class ScatterplotFacet implements Facet {
     public void computeChoices(Project project, FilteredRecords filteredRecords) {
         if (eval_x != null && eval_y != null && errorMessage_x == null && errorMessage_y == null) {
             Column column_x = project.columnModel.getColumnByCellIndex(columnIndex_x);
-            NumericBinIndex index_x = getBinIndex(project, column_x, eval_x, expression_x, "record-based");
+            NumericBinIndex index_x = getBinIndex(project, column_x, eval_x, config.expression_x, "record-based");
             
             Column column_y = project.columnModel.getColumnByCellIndex(columnIndex_y);
-            NumericBinIndex index_y = getBinIndex(project, column_y, eval_y, expression_y, "record-based");
+            NumericBinIndex index_y = getBinIndex(project, column_y, eval_y, config.expression_y, "record-based");
             
             retrieveDataFromBinIndices(index_x, index_y);
             
@@ -365,7 +424,7 @@ public class ScatterplotFacet implements Facet {
                 if (index_x.isNumeric() && index_y.isNumeric()) {
                     ScatterplotDrawingRowVisitor drawer = new ScatterplotDrawingRowVisitor(
                       columnIndex_x, columnIndex_y, min_x, max_x, min_y, max_y, 
-                      size, dim_x, dim_y, rotation, dot, color
+                      config.size, config.dim_x, config.dim_y, config.rotation, config.dot, config.color
                     );
                     filteredRecords.accept(project, drawer);
                  
@@ -402,16 +461,6 @@ public class ScatterplotFacet implements Facet {
         return ("log".equals(type.toLowerCase())) ? LOG : LIN;
     }
    
-    public static int getRotation(String rotation) {
-        rotation = rotation.toLowerCase();
-        if ("cw".equals(rotation) || "right".equals(rotation)) {
-            return ScatterplotFacet.ROTATE_CW;
-        } else if ("ccw".equals(rotation) || "left".equals(rotation)) {
-            return ScatterplotFacet.ROTATE_CCW;
-        } else {
-            return NO_ROTATION;
-        }
-    }
     
     public static NumericBinIndex getBinIndex(Project project, Column column, Evaluable eval, String expression) {
         return getBinIndex(project, column, eval, expression, "row-based");

main/src/com/google/refine/browsing/facets/TextSearchFacet.java

@@ -53,21 +53,59 @@ import com.google.refine.model.Project;
 import com.google.refine.util.PatternSyntaxExceptionParser;
 
 public class TextSearchFacet implements Facet {
+    
     /*
      *  Configuration
      */
+    public static class TextSearchFacetConfig implements FacetConfig {  
         protected String     _name;
         protected String     _columnName;
-    protected String     _query;
+        protected String     _query = null;
         protected String     _mode;
         protected boolean    _caseSensitive;
         protected boolean    _invert;
         
+        @Override
+        public void write(JSONWriter writer, Properties options)
+                throws JSONException {
+            writer.object();
+            writer.key("name"); writer.value(_name);
+            writer.key("columnName"); writer.value(_columnName);
+            writer.key("query"); writer.value(_query);
+            writer.key("mode"); writer.value(_mode);
+            writer.key("caseSensitive"); writer.value(_caseSensitive);
+            writer.key("invert"); writer.value(_invert);
+            writer.key("type"); writer.value("text");
+            writer.endObject();  
+        }
+        
+        @Override
+        public TextSearchFacet apply(Project project) {
+            TextSearchFacet facet = new TextSearchFacet();
+            facet.initializeFromConfig(this, project);
+            return facet;
+        }
+        
+        @Override
+        public void initializeFromJSON(JSONObject o) {
+            _name = o.getString("name");
+            _columnName = o.getString("columnName");
+            _mode = o.getString("mode");
+            _caseSensitive = o.getBoolean("caseSensitive");
+            if (!o.isNull("query")) {
+                _query = o.getString("query"); 
+            }
+            _invert = o.has("invert") && o.getBoolean("invert");
+        }
+    }
+    TextSearchFacetConfig _config = new TextSearchFacetConfig();
+    
     /*
      *  Derived configuration
      */
     protected int        _cellIndex;
     protected Pattern    _pattern;
+    protected String     _query; // normalized version of the query from the config
     
     public TextSearchFacet() {
     }
@@ -77,68 +115,61 @@ public class TextSearchFacet implements Facet {
             throws JSONException {
         
         writer.object();
-        writer.key("name"); writer.value(_name);
+        writer.key("name"); writer.value(_config._name);
-        writer.key("columnName"); writer.value(_columnName);
+        writer.key("columnName"); writer.value(_config._columnName);
-        writer.key("query"); writer.value(_query);
+        writer.key("query"); writer.value(_config._query);
-        writer.key("mode"); writer.value(_mode);
+        writer.key("mode"); writer.value(_config._mode);
-        writer.key("caseSensitive"); writer.value(_caseSensitive);
+        writer.key("caseSensitive"); writer.value(_config._caseSensitive);
-        writer.key("invert"); writer.value(_invert);
+        writer.key("invert"); writer.value(_config._invert);
         writer.endObject();
     }
     
-    @Override
+    public void initializeFromConfig(TextSearchFacetConfig config, Project project) {
-    public void initializeFromJSON(Project project, JSONObject o) throws JSONException {
+        _config = config;
-        _name = o.getString("name");
-        _columnName = o.getString("columnName");
         
-        Column column = project.columnModel.getColumnByName(_columnName);
+        Column column = project.columnModel.getColumnByName(_config._columnName);
         _cellIndex = column != null ? column.getCellIndex() : -1;
         
-        if (!o.isNull("query")) {
+        _query = _config._query;
-            _query = o.getString("query"); 
-        }
-        
-        _mode = o.getString("mode");
-        _caseSensitive = o.getBoolean("caseSensitive");
         if (_query != null) {
-            if ("regex".equals(_mode)) {
+            if ("regex".equals(_config._mode)) {
                 try {
                     _pattern = Pattern.compile(
                             _query, 
-                            _caseSensitive ? 0 : Pattern.CASE_INSENSITIVE);
+                            _config._caseSensitive ? 0 : Pattern.CASE_INSENSITIVE);
                 } catch (java.util.regex.PatternSyntaxException e) {
                     PatternSyntaxExceptionParser err = new PatternSyntaxExceptionParser(e);
                     throw new JSONException(err.getUserMessage());
                 }
-            } else if (!_caseSensitive) {
+            } else if (!_config._caseSensitive) {
                 _query = _query.toLowerCase();
             }
         }
-        _invert = o.has("invert") && o.getBoolean("invert");
+
     }
 
     @Override
     public RowFilter getRowFilter(Project project) {
         if (_query == null || _query.length() == 0 || _cellIndex < 0) {
             return null;
-        } else if ("regex".equals(_mode) && _pattern == null) {
+        } else if ("regex".equals(_config._mode) && _pattern == null) {
             return null;
         }
         
         Evaluable eval = new VariableExpr("value");
         
-        if ("regex".equals(_mode)) {
+        if ("regex".equals(_config._mode)) {
-            return new ExpressionStringComparisonRowFilter(eval, _invert, _columnName, _cellIndex) {
+            return new ExpressionStringComparisonRowFilter(eval, _config._invert, _config._columnName, _cellIndex) {
                 @Override
                 protected boolean checkValue(String s) {
                     return _pattern.matcher(s).find();
                 };
             };
         } else {
-            return new ExpressionStringComparisonRowFilter(eval, _invert, _columnName, _cellIndex) {
+            return new ExpressionStringComparisonRowFilter(eval, _config._invert, _config._columnName, _cellIndex) {
                 @Override
                 protected boolean checkValue(String s) {
-                    return (_caseSensitive ? s : s.toLowerCase()).contains(_query);
+                    return (_config._caseSensitive ? s : s.toLowerCase()).contains(_query);
                 };
             };
         }        

main/src/com/google/refine/browsing/facets/TimeRangeFacet.java

@@ -41,37 +41,129 @@ import org.json.JSONWriter;
 
 import com.google.refine.browsing.FilteredRecords;
 import com.google.refine.browsing.FilteredRows;
+import com.google.refine.browsing.RecordFilter;
 import com.google.refine.browsing.RowFilter;
+import com.google.refine.browsing.filters.AnyRowRecordFilter;
 import com.google.refine.browsing.filters.ExpressionTimeComparisonRowFilter;
+import com.google.refine.browsing.util.ExpressionBasedRowEvaluable;
 import com.google.refine.browsing.util.ExpressionTimeValueBinner;
 import com.google.refine.browsing.util.RowEvaluable;
 import com.google.refine.browsing.util.TimeBinIndex;
 import com.google.refine.browsing.util.TimeBinRecordIndex;
 import com.google.refine.browsing.util.TimeBinRowIndex;
+import com.google.refine.expr.Evaluable;
 import com.google.refine.expr.MetaParser;
 import com.google.refine.expr.ParsingException;
 import com.google.refine.model.Column;
 import com.google.refine.model.Project;
 import com.google.refine.util.JSONUtilities;
 
-public class TimeRangeFacet extends RangeFacet {
+public class TimeRangeFacet implements Facet {
+    /*
+     * Configuration, from the client side
+     */
+    public static class TimeRangeFacetConfig implements FacetConfig {
+        protected String     _name;       // name of facet
+        protected String     _expression; // expression to compute numeric value(s) per row
+        protected String     _columnName; // column to base expression on, if any
+        
+        protected double      _from; // the numeric selection
+        protected double      _to;
         
         protected boolean   _selectTime; // whether the time selection applies, default true
         protected boolean   _selectNonTime;
+        protected boolean   _selectBlank;
+        protected boolean   _selectError;
         
+        protected boolean    _selected; // false if we're certain that all rows will match
+                        // and there isn't any filtering to do
+        
+        @Override
+        public void write(JSONWriter writer, Properties options)
+                throws JSONException {
+            writer.object();
+            writer.key("type"); writer.value("timerange");
+            writer.key("name"); writer.value(_name);
+            writer.key("expression"); writer.value(_expression);
+            writer.key("columnName"); writer.value(_columnName);
+            writer.key("selectTime"); writer.value(_selectTime);
+            writer.key("selectNonTime"); writer.value(_selectNonTime);
+            writer.key("selectBlank"); writer.value(_selectBlank);
+            writer.key("selectError"); writer.value(_selectError);
+            writer.key(FROM); writer.value((long)_from);
+            writer.key(TO); writer.value((long)_to);
+            writer.endObject();
+        }
+        
+        @Override
+        public void initializeFromJSON(JSONObject o) throws JSONException {        
+            _name = o.getString("name");
+            _expression = o.getString("expression");
+            _columnName = o.getString("columnName");
+            
+            if (o.has(FROM) || o.has(TO)) {
+                _from = o.has(FROM) ? o.getDouble(FROM) : 0;
+                _to = o.has(TO) ? o.getDouble(TO) : 0;
+                _selected = true;
+            }
+            
+            _selectTime = JSONUtilities.getBoolean(o, "selectTime", true);
+            _selectNonTime = JSONUtilities.getBoolean(o, "selectNonTime", true);
+            _selectBlank = JSONUtilities.getBoolean(o, "selectBlank", true);
+            _selectError = JSONUtilities.getBoolean(o, "selectError", true);
+            
+            if (!_selectTime || !_selectNonTime || !_selectBlank || !_selectError) {
+                _selected = true;
+            }
+        }
+        
+        @Override
+        public TimeRangeFacet apply(Project project) {
+            TimeRangeFacet facet = new TimeRangeFacet();
+            facet.initializeFromConfig(this, project);
+            return facet;
+        }
+    }
+    protected TimeRangeFacetConfig _config;
+    
+    /*
+     * Derived configuration data
+     */
+    protected int        _cellIndex;
+    protected Evaluable  _eval;
+    protected String     _errorMessage;
+    
+    protected double    _min;
+    protected double    _max;
+    protected double    _step;
+    protected int[]     _baseBins;
+    protected int[]     _bins;
+    
+    /*
+     * Computed data
+     */
     protected int       _baseTimeCount;
     protected int       _baseNonTimeCount;
+    protected int       _baseBlankCount;
+    protected int       _baseErrorCount;
       
     protected int       _timeCount;
     protected int       _nonTimeCount;
+    protected int       _blankCount;
+    protected int       _errorCount;
+
+    protected static final String MIN = "min";
+    protected static final String MAX = "max";
+    protected static final String TO = "to";
+    protected static final String FROM = "from";
     
     @Override
     public void write(JSONWriter writer, Properties options) throws JSONException {
         
         writer.object();
-        writer.key("name"); writer.value(_name);
+        writer.key("name"); writer.value(_config._name);
-        writer.key("expression"); writer.value(_expression);
+        writer.key("expression"); writer.value(_config._expression);
-        writer.key("columnName"); writer.value(_columnName);
+        writer.key("columnName"); writer.value(_config._columnName);
         
         if (_errorMessage != null) {
             writer.key("error"); writer.value(_errorMessage);
@@ -93,8 +185,8 @@ public class TimeRangeFacet extends RangeFacet {
                 }
                 writer.endArray();
                 
-                writer.key(FROM); writer.value(_from);
+                writer.key(FROM); writer.value(_config._from);
-                writer.key(TO); writer.value(_to);
+                writer.key(TO); writer.value(_config._to);
             }
             
             writer.key("baseTimeCount"); writer.value(_baseTimeCount);
@@ -110,54 +202,35 @@ public class TimeRangeFacet extends RangeFacet {
         writer.endObject();
     }
     
-    @Override
+    public void initializeFromConfig(TimeRangeFacetConfig config, Project project) {
-    public void initializeFromJSON(Project project, JSONObject o) throws JSONException {
+        _config = config;
-        _name = o.getString("name");
+        if (_config._columnName.length() > 0) {
-        _expression = o.getString("expression");
+            Column column = project.columnModel.getColumnByName(_config._columnName);
-        _columnName = o.getString("columnName");
-        
-        if (_columnName.length() > 0) {
-            Column column = project.columnModel.getColumnByName(_columnName);
             if (column != null) {
                 _cellIndex = column.getCellIndex();
             } else {
-                _errorMessage = "No column named " + _columnName;
+                _errorMessage = "No column named " + _config._columnName;
             }
         } else {
             _cellIndex = -1;
         }
         
         try {
-            _eval = MetaParser.parse(_expression);
+            _eval = MetaParser.parse(_config._expression);
         } catch (ParsingException e) {
             _errorMessage = e.getMessage();
         }
-        
-        if (o.has(FROM) || o.has(TO)) {
-            _from = o.has(FROM) ? o.getDouble(FROM) : _min;
-            _to = o.has(TO) ? o.getDouble(TO) : _max;
-            _selected = true;
-        }
-        
-        _selectTime = JSONUtilities.getBoolean(o, "selectTime", true);
-        _selectNonTime = JSONUtilities.getBoolean(o, "selectNonTime", true);
-        _selectBlank = JSONUtilities.getBoolean(o, "selectBlank", true);
-        _selectError = JSONUtilities.getBoolean(o, "selectError", true);
-        
-        if (!_selectTime || !_selectNonTime || !_selectBlank || !_selectError) {
-            _selected = true;
-        }
     }
 
     @Override
     public RowFilter getRowFilter(Project project) {
-        if (_eval != null && _errorMessage == null && _selected) {
+        if (_eval != null && _errorMessage == null && _config._selected) {
             return new ExpressionTimeComparisonRowFilter(
-                    getRowEvaluable(project), _selectTime, _selectNonTime, _selectBlank, _selectError) {
+                    getRowEvaluable(project), _config._selectTime, _config._selectNonTime, _config._selectBlank, _config._selectError) {
                 
                 @Override
                 protected boolean checkValue(long t) {
-                    return t >= _from && t <= _to;
+                    return t >= _config._from && t <= _config._to;
                 };
             };
         } else {
@@ -171,7 +244,7 @@ public class TimeRangeFacet extends RangeFacet {
             RowEvaluable rowEvaluable = getRowEvaluable(project);
             
             Column column = project.columnModel.getColumnByCellIndex(_cellIndex);
-            String key = "time-bin:row-based:" + _expression;
+            String key = "time-bin:row-based:" + _config._expression;
             TimeBinIndex index = (TimeBinIndex) column.getPrecompute(key);
             if (index == null) {
                 index = new TimeBinRowIndex(project, rowEvaluable);
@@ -193,7 +266,7 @@ public class TimeRangeFacet extends RangeFacet {
             RowEvaluable rowEvaluable = getRowEvaluable(project);
             
             Column column = project.columnModel.getColumnByCellIndex(_cellIndex);
-            String key = "time-bin:record-based:" + _expression;
+            String key = "time-bin:record-based:" + _config._expression;
             TimeBinIndex index = (TimeBinIndex) column.getPrecompute(key);
             if (index == null) {
                 index = new TimeBinRecordIndex(project, rowEvaluable);
@@ -221,12 +294,12 @@ public class TimeRangeFacet extends RangeFacet {
         _baseBlankCount = index.getBlankRowCount();
         _baseErrorCount = index.getErrorRowCount();
         
-        if (_selected) {
+        if (_config._selected) {
-            _from = Math.max(_from, _min);
+            _config._from = Math.max(_config._from, _min);
-            _to = Math.min(_to, _max);
+            _config._to = Math.min(_config._to, _max);
         } else {
-            _from = _min;
+            _config._from = _min;
-            _to = _max;
+            _config._to = _max;
         }
     }
     
@@ -237,4 +310,14 @@ public class TimeRangeFacet extends RangeFacet {
         _blankCount = binner.blankCount;
         _errorCount = binner.errorCount;
     }
+
+    @Override
+    public RecordFilter getRecordFilter(Project project) {
+        RowFilter rowFilter = getRowFilter(project);
+        return rowFilter == null ? null : new AnyRowRecordFilter(rowFilter);
+    }
+    
+    protected RowEvaluable getRowEvaluable(Project project) {
+        return new ExpressionBasedRowEvaluable(_config._columnName, _cellIndex, _eval);
+    }
 }

main/src/com/google/refine/commands/Command.java

@@ -54,6 +54,7 @@ import com.google.refine.Jsonizable;
 import com.google.refine.ProjectManager;
 import com.google.refine.RefineServlet;
 import com.google.refine.browsing.Engine;
+import com.google.refine.browsing.EngineConfig;
 import com.google.refine.history.HistoryEntry;
 import com.google.refine.model.Project;
 import com.google.refine.model.metadata.ProjectMetadata;
@@ -115,7 +116,7 @@ public abstract class Command {
      * @return
      * @throws JSONException
      */
-    static protected JSONObject getEngineConfig(HttpServletRequest request)
+    static protected EngineConfig getEngineConfig(HttpServletRequest request)
     throws JSONException {
         if (request == null) {
             throw new IllegalArgumentException("parameter 'request' should not be null");
@@ -123,7 +124,8 @@ public abstract class Command {
         
         String json = request.getParameter("engine");
         try{
-            return (json == null) ? null : ParsingUtilities.evaluateJsonStringToObject(json);
+            return (json == null) ? null :
+                   EngineConfig.reconstruct(ParsingUtilities.evaluateJsonStringToObject(json));
         } catch (JSONException e){
             logger.debug( json + " could not be parsed to JSON");
             return null;
@@ -149,9 +151,9 @@ public abstract class Command {
         }
 
         Engine engine = new Engine(project);
-        JSONObject o = getEngineConfig(request);
+        EngineConfig c = getEngineConfig(request);
-        if (o != null) {
+        if (c != null) {
-            engine.initializeFromJSON(o);
+            engine.initializeFromConfig(c);
         }
         return engine;
     }

main/src/com/google/refine/commands/EngineDependentCommand.java

@@ -40,8 +40,7 @@ import javax.servlet.ServletException;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 
-import org.json.JSONObject;
+import com.google.refine.browsing.EngineConfig;
-
 import com.google.refine.model.AbstractOperation;
 import com.google.refine.model.Project;
 import com.google.refine.process.Process;
@@ -85,5 +84,5 @@ abstract public class EngineDependentCommand extends Command {
     }
     
     abstract protected AbstractOperation createOperation(
-            Project project, HttpServletRequest request, JSONObject engineConfig) throws Exception;
+            Project project, HttpServletRequest request, EngineConfig engineConfig) throws Exception;
 }

main/src/com/google/refine/commands/browsing/GetScatterplotCommand.java

@@ -53,6 +53,7 @@ import com.google.refine.browsing.Engine;
 import com.google.refine.browsing.FilteredRows;
 import com.google.refine.browsing.facets.ScatterplotDrawingRowVisitor;
 import com.google.refine.browsing.facets.ScatterplotFacet;
+import com.google.refine.browsing.facets.ScatterplotFacet.ScatterplotFacetConfig;
 import com.google.refine.browsing.util.NumericBinIndex;
 import com.google.refine.commands.Command;
 import com.google.refine.expr.Evaluable;
@@ -114,7 +115,7 @@ public class GetScatterplotCommand extends Command {
         int dim_x = (o.has(ScatterplotFacet.DIM_X)) ? ScatterplotFacet.getAxisDim(o.getString(ScatterplotFacet.DIM_X)) : ScatterplotFacet.LIN;
         int dim_y = (o.has(ScatterplotFacet.DIM_Y)) ? ScatterplotFacet.getAxisDim(o.getString(ScatterplotFacet.DIM_Y)) : ScatterplotFacet.LIN;
 
-        int rotation = (o.has(ScatterplotFacet.ROTATION)) ? ScatterplotFacet.getRotation(o.getString(ScatterplotFacet.ROTATION)) : ScatterplotFacet.NO_ROTATION;
+        int rotation = (o.has(ScatterplotFacet.ROTATION)) ? ScatterplotFacetConfig.getRotation(o.getString(ScatterplotFacet.ROTATION)) : ScatterplotFacet.NO_ROTATION;
         
         String color_str = (o.has(ScatterplotFacet.COLOR)) ? o.getString(ScatterplotFacet.COLOR) : "000000";
         Color color = new Color(Integer.parseInt(color_str,16));

main/src/com/google/refine/commands/cell/BlankDownCommand.java

@@ -35,8 +35,7 @@ package com.google.refine.commands.cell;
 
 import javax.servlet.http.HttpServletRequest;
 
-import org.json.JSONObject;
+import com.google.refine.browsing.EngineConfig;
-
 import com.google.refine.commands.EngineDependentCommand;
 import com.google.refine.model.AbstractOperation;
 import com.google.refine.model.Project;
@@ -45,7 +44,7 @@ import com.google.refine.operations.cell.BlankDownOperation;
 public class BlankDownCommand extends EngineDependentCommand {
     @Override
     protected AbstractOperation createOperation(Project project,
-            HttpServletRequest request, JSONObject engineConfig) throws Exception {
+            HttpServletRequest request, EngineConfig engineConfig) throws Exception {
         
         String columnName = request.getParameter("columnName");
         

main/src/com/google/refine/commands/cell/FillDownCommand.java

@@ -35,8 +35,7 @@ package com.google.refine.commands.cell;
 
 import javax.servlet.http.HttpServletRequest;
 
-import org.json.JSONObject;
+import com.google.refine.browsing.EngineConfig;
-
 import com.google.refine.commands.EngineDependentCommand;
 import com.google.refine.model.AbstractOperation;
 import com.google.refine.model.Project;
@@ -45,7 +44,7 @@ import com.google.refine.operations.cell.FillDownOperation;
 public class FillDownCommand extends EngineDependentCommand {
     @Override
     protected AbstractOperation createOperation(Project project,
-            HttpServletRequest request, JSONObject engineConfig) throws Exception {
+            HttpServletRequest request, EngineConfig engineConfig) throws Exception {
         
         String columnName = request.getParameter("columnName");
         

main/src/com/google/refine/commands/cell/MassEditCommand.java

@@ -35,8 +35,7 @@ package com.google.refine.commands.cell;
 
 import javax.servlet.http.HttpServletRequest;
 
-import org.json.JSONObject;
+import com.google.refine.browsing.EngineConfig;
-
 import com.google.refine.commands.EngineDependentCommand;
 import com.google.refine.model.AbstractOperation;
 import com.google.refine.model.Project;
@@ -46,7 +45,7 @@ import com.google.refine.util.ParsingUtilities;
 public class MassEditCommand extends EngineDependentCommand {
     @Override
     protected AbstractOperation createOperation(Project project,
-            HttpServletRequest request, JSONObject engineConfig) throws Exception {
+            HttpServletRequest request, EngineConfig engineConfig) throws Exception {
         
         String columnName = request.getParameter("columnName");
         String expression = request.getParameter("expression");

main/src/com/google/refine/commands/cell/TextTransformCommand.java

@@ -35,8 +35,7 @@ package com.google.refine.commands.cell;
 
 import javax.servlet.http.HttpServletRequest;
 
-import org.json.JSONObject;
+import com.google.refine.browsing.EngineConfig;
-
 import com.google.refine.commands.EngineDependentCommand;
 import com.google.refine.model.AbstractOperation;
 import com.google.refine.model.Project;
@@ -45,7 +44,7 @@ import com.google.refine.operations.cell.TextTransformOperation;
 public class TextTransformCommand extends EngineDependentCommand {
     @Override
     protected AbstractOperation createOperation(Project project,
-            HttpServletRequest request, JSONObject engineConfig) throws Exception {
+            HttpServletRequest request, EngineConfig engineConfig) throws Exception {
         
         String columnName = request.getParameter("columnName");
         String expression = request.getParameter("expression");

main/src/com/google/refine/commands/column/AddColumnByFetchingURLsCommand.java

@@ -35,9 +35,9 @@ package com.google.refine.commands.column;
 
 import javax.servlet.http.HttpServletRequest;
 
-import org.json.JSONObject;
 import org.json.JSONArray;
 
+import com.google.refine.browsing.EngineConfig;
 import com.google.refine.commands.EngineDependentCommand;
 import com.google.refine.model.AbstractOperation;
 import com.google.refine.model.Project;
@@ -47,7 +47,7 @@ import com.google.refine.operations.column.ColumnAdditionByFetchingURLsOperation
 public class AddColumnByFetchingURLsCommand extends EngineDependentCommand {
     @Override
     protected AbstractOperation createOperation(Project project,
-        HttpServletRequest request, JSONObject engineConfig) throws Exception {
+        HttpServletRequest request, EngineConfig engineConfig) throws Exception {
         
         String baseColumnName = request.getParameter("baseColumnName");
         String urlExpression = request.getParameter("urlExpression");

main/src/com/google/refine/commands/column/AddColumnCommand.java

@@ -35,8 +35,7 @@ package com.google.refine.commands.column;
 
 import javax.servlet.http.HttpServletRequest;
 
-import org.json.JSONObject;
+import com.google.refine.browsing.EngineConfig;
-
 import com.google.refine.commands.EngineDependentCommand;
 import com.google.refine.model.AbstractOperation;
 import com.google.refine.model.Project;
@@ -46,7 +45,7 @@ import com.google.refine.operations.column.ColumnAdditionOperation;
 public class AddColumnCommand extends EngineDependentCommand {
     @Override
     protected AbstractOperation createOperation(Project project,
-            HttpServletRequest request, JSONObject engineConfig) throws Exception {
+            HttpServletRequest request, EngineConfig engineConfig) throws Exception {
         
         String baseColumnName = request.getParameter("baseColumnName");
         String expression = request.getParameter("expression");

main/src/com/google/refine/commands/column/ReorderColumnsCommand.java

@@ -35,8 +35,7 @@ package com.google.refine.commands.column;
 
 import javax.servlet.http.HttpServletRequest;
 
-import org.json.JSONObject;
+import com.google.refine.browsing.EngineConfig;
-
 import com.google.refine.commands.EngineDependentCommand;
 import com.google.refine.model.AbstractOperation;
 import com.google.refine.model.Project;
@@ -48,7 +47,7 @@ public class ReorderColumnsCommand extends EngineDependentCommand {
     
     @Override
     protected AbstractOperation createOperation(Project project,
-            HttpServletRequest request, JSONObject engineConfig) throws Exception {
+            HttpServletRequest request, EngineConfig engineConfig) throws Exception {
         
         String columnNames = request.getParameter("columnNames");
         return new ColumnReorderOperation(

main/src/com/google/refine/commands/column/SplitColumnCommand.java

@@ -36,8 +36,8 @@ package com.google.refine.commands.column;
 import javax.servlet.http.HttpServletRequest;
 
 import org.json.JSONArray;
-import org.json.JSONObject;
 
+import com.google.refine.browsing.EngineConfig;
 import com.google.refine.commands.EngineDependentCommand;
 import com.google.refine.model.AbstractOperation;
 import com.google.refine.model.Project;
@@ -47,7 +47,7 @@ import com.google.refine.util.ParsingUtilities;
 public class SplitColumnCommand extends EngineDependentCommand {
     @Override
     protected AbstractOperation createOperation(Project project,
-            HttpServletRequest request, JSONObject engineConfig) throws Exception {
+            HttpServletRequest request, EngineConfig engineConfig) throws Exception {
         
         String columnName = request.getParameter("columnName");
         boolean guessCellType = Boolean.parseBoolean(request.getParameter("guessCellType"));

main/src/com/google/refine/commands/recon/ExtendDataCommand.java

@@ -37,6 +37,7 @@ import javax.servlet.http.HttpServletRequest;
 
 import org.json.JSONObject;
 
+import com.google.refine.browsing.EngineConfig;
 import com.google.refine.commands.EngineDependentCommand;
 import com.google.refine.operations.recon.ExtendDataOperation;
 import com.google.refine.model.AbstractOperation;
@@ -46,7 +47,7 @@ import com.google.refine.util.ParsingUtilities;
 public class ExtendDataCommand extends EngineDependentCommand {
     @Override
     protected AbstractOperation createOperation(Project project,
-            HttpServletRequest request, JSONObject engineConfig) throws Exception {
+            HttpServletRequest request, EngineConfig engineConfig) throws Exception {
         
         String baseColumnName = request.getParameter("baseColumnName");
         int columnInsertIndex = Integer.parseInt(request.getParameter("columnInsertIndex"));

main/src/com/google/refine/commands/recon/ReconClearSimilarCellsCommand.java

@@ -35,8 +35,7 @@ package com.google.refine.commands.recon;
 
 import javax.servlet.http.HttpServletRequest;
 
-import org.json.JSONObject;
+import com.google.refine.browsing.EngineConfig;
-
 import com.google.refine.commands.EngineDependentCommand;
 import com.google.refine.model.AbstractOperation;
 import com.google.refine.model.Project;
@@ -46,7 +45,7 @@ public class ReconClearSimilarCellsCommand extends EngineDependentCommand {
 
     @Override
     protected AbstractOperation createOperation(
-            Project project, HttpServletRequest request, JSONObject engineConfig) throws Exception {
+            Project project, HttpServletRequest request, EngineConfig engineConfig) throws Exception {
         
         String columnName = request.getParameter("columnName");
         String similarValue = request.getParameter("similarValue");

main/src/com/google/refine/commands/recon/ReconCopyAcrossColumnsCommand.java

@@ -35,8 +35,7 @@ package com.google.refine.commands.recon;
 
 import javax.servlet.http.HttpServletRequest;
 
-import org.json.JSONObject;
+import com.google.refine.browsing.EngineConfig;
-
 import com.google.refine.commands.EngineDependentCommand;
 import com.google.refine.model.AbstractOperation;
 import com.google.refine.model.Project;
@@ -45,7 +44,7 @@ import com.google.refine.operations.recon.ReconCopyAcrossColumnsOperation;
 public class ReconCopyAcrossColumnsCommand extends EngineDependentCommand {
     @Override
     protected AbstractOperation createOperation(Project project,
-            HttpServletRequest request, JSONObject engineConfig) throws Exception {
+            HttpServletRequest request, EngineConfig engineConfig) throws Exception {
         
         String fromColumnName = request.getParameter("fromColumnName");
         String[] toColumnNames = request.getParameterValues("toColumnName[]");

main/src/com/google/refine/commands/recon/ReconDiscardJudgmentsCommand.java

@@ -35,8 +35,7 @@ package com.google.refine.commands.recon;
 
 import javax.servlet.http.HttpServletRequest;
 
-import org.json.JSONObject;
+import com.google.refine.browsing.EngineConfig;
-
 import com.google.refine.commands.EngineDependentCommand;
 import com.google.refine.model.AbstractOperation;
 import com.google.refine.model.Project;
@@ -45,7 +44,7 @@ import com.google.refine.operations.recon.ReconDiscardJudgmentsOperation;
 public class ReconDiscardJudgmentsCommand extends EngineDependentCommand {
     @Override
     protected AbstractOperation createOperation(Project project,
-            HttpServletRequest request, JSONObject engineConfig) throws Exception {
+            HttpServletRequest request, EngineConfig engineConfig) throws Exception {
         
         String columnName = request.getParameter("columnName");
         boolean clearData = Boolean.parseBoolean(request.getParameter("clearData"));

main/src/com/google/refine/commands/recon/ReconJudgeSimilarCellsCommand.java

@@ -35,8 +35,7 @@ package com.google.refine.commands.recon;
 
 import javax.servlet.http.HttpServletRequest;
 
-import org.json.JSONObject;
+import com.google.refine.browsing.EngineConfig;
-
 import com.google.refine.commands.EngineDependentCommand;
 import com.google.refine.model.AbstractOperation;
 import com.google.refine.model.Project;
@@ -49,7 +48,7 @@ public class ReconJudgeSimilarCellsCommand extends EngineDependentCommand {
 
     @Override
     protected AbstractOperation createOperation(
-            Project project, HttpServletRequest request, JSONObject engineConfig) throws Exception {
+            Project project, HttpServletRequest request, EngineConfig engineConfig) throws Exception {
         
         String columnName = request.getParameter("columnName");
         String similarValue = request.getParameter("similarValue");

main/src/com/google/refine/commands/recon/ReconMarkNewTopicsCommand.java

@@ -35,8 +35,7 @@ package com.google.refine.commands.recon;
 
 import javax.servlet.http.HttpServletRequest;
 
-import org.json.JSONObject;
+import com.google.refine.browsing.EngineConfig;
-
 import com.google.refine.commands.EngineDependentCommand;
 import com.google.refine.model.AbstractOperation;
 import com.google.refine.model.Project;
@@ -46,7 +45,7 @@ public class ReconMarkNewTopicsCommand extends EngineDependentCommand {
     
     @Override
     protected AbstractOperation createOperation(Project project,
-            HttpServletRequest request, JSONObject engineConfig) throws Exception {
+            HttpServletRequest request, EngineConfig engineConfig) throws Exception {
         
         return new ReconMarkNewTopicsOperation(
             engineConfig, 

main/src/com/google/refine/commands/recon/ReconMatchBestCandidatesCommand.java

@@ -35,8 +35,7 @@ package com.google.refine.commands.recon;
 
 import javax.servlet.http.HttpServletRequest;
 
-import org.json.JSONObject;
+import com.google.refine.browsing.EngineConfig;
-
 import com.google.refine.commands.EngineDependentCommand;
 import com.google.refine.model.AbstractOperation;
 import com.google.refine.model.Project;
@@ -46,7 +45,7 @@ public class ReconMatchBestCandidatesCommand extends EngineDependentCommand {
     
     @Override
     protected AbstractOperation createOperation(Project project,
-            HttpServletRequest request, JSONObject engineConfig) throws Exception {
+            HttpServletRequest request, EngineConfig engineConfig) throws Exception {
         
         String columnName = request.getParameter("columnName");
         

main/src/com/google/refine/commands/recon/ReconMatchSpecificTopicCommand.java

@@ -35,8 +35,7 @@ package com.google.refine.commands.recon;
 
 import javax.servlet.http.HttpServletRequest;
 
-import org.json.JSONObject;
+import com.google.refine.browsing.EngineConfig;
-
 import com.google.refine.commands.EngineDependentCommand;
 import com.google.refine.model.AbstractOperation;
 import com.google.refine.model.Project;
@@ -47,7 +46,7 @@ public class ReconMatchSpecificTopicCommand extends EngineDependentCommand {
     
     @Override
     protected AbstractOperation createOperation(Project project,
-            HttpServletRequest request, JSONObject engineConfig) throws Exception {
+            HttpServletRequest request, EngineConfig engineConfig) throws Exception {
         
         String columnName = request.getParameter("columnName");
         ReconCandidate match = new ReconCandidate(

main/src/com/google/refine/commands/recon/ReconcileCommand.java

@@ -38,6 +38,7 @@ import javax.servlet.http.HttpServletRequest;
 import org.json.JSONObject;
 import org.json.JSONTokener;
 
+import com.google.refine.browsing.EngineConfig;
 import com.google.refine.commands.EngineDependentCommand;
 import com.google.refine.model.AbstractOperation;
 import com.google.refine.model.Project;
@@ -48,7 +49,7 @@ public class ReconcileCommand extends EngineDependentCommand {
     
     @Override
     protected AbstractOperation createOperation(Project project,
-            HttpServletRequest request, JSONObject engineConfig) throws Exception {
+            HttpServletRequest request, EngineConfig engineConfig) throws Exception {
         
         String columnName = request.getParameter("columnName");
         String configString = request.getParameter("config");

main/src/com/google/refine/commands/row/AnnotateRowsCommand.java

@@ -35,8 +35,7 @@ package com.google.refine.commands.row;
 
 import javax.servlet.http.HttpServletRequest;
 
-import org.json.JSONObject;
+import com.google.refine.browsing.EngineConfig;
-
 import com.google.refine.commands.EngineDependentCommand;
 import com.google.refine.model.AbstractOperation;
 import com.google.refine.model.Project;
@@ -47,7 +46,7 @@ public class AnnotateRowsCommand extends EngineDependentCommand {
     
     @Override
     protected AbstractOperation createOperation(Project project,
-            HttpServletRequest request, JSONObject engineConfig) throws Exception {
+            HttpServletRequest request, EngineConfig engineConfig) throws Exception {
         
         String starredString = request.getParameter("starred");
         if (starredString != null) {

main/src/com/google/refine/commands/row/RemoveRowsCommand.java

@@ -35,8 +35,7 @@ package com.google.refine.commands.row;
 
 import javax.servlet.http.HttpServletRequest;
 
-import org.json.JSONObject;
+import com.google.refine.browsing.EngineConfig;
-
 import com.google.refine.commands.EngineDependentCommand;
 import com.google.refine.model.AbstractOperation;
 import com.google.refine.model.Project;
@@ -46,7 +45,7 @@ public class RemoveRowsCommand extends EngineDependentCommand {
     
     @Override
     protected AbstractOperation createOperation(Project project,
-            HttpServletRequest request, JSONObject engineConfig) throws Exception {
+            HttpServletRequest request, EngineConfig engineConfig) throws Exception {
         
         return new RowRemovalOperation(engineConfig);
     }

main/src/com/google/refine/commands/row/ReorderRowsCommand.java

@@ -39,6 +39,7 @@ import org.json.JSONException;
 import org.json.JSONObject;
 
 import com.google.refine.browsing.Engine;
+import com.google.refine.browsing.EngineConfig;
 import com.google.refine.commands.EngineDependentCommand;
 import com.google.refine.model.AbstractOperation;
 import com.google.refine.model.Project;
@@ -49,7 +50,7 @@ public class ReorderRowsCommand extends EngineDependentCommand {
     
     @Override
     protected AbstractOperation createOperation(Project project,
-            HttpServletRequest request, JSONObject engineConfig) throws Exception {
+            HttpServletRequest request, EngineConfig engineConfig) throws Exception {
 
         String mode = request.getParameter("mode");
         JSONObject sorting = null;

main/src/com/google/refine/operations/EngineDependentMassCellOperation.java

@@ -36,9 +36,8 @@ package com.google.refine.operations;
 import java.util.ArrayList;
 import java.util.List;
 
-import org.json.JSONObject;
-
 import com.google.refine.browsing.Engine;
+import com.google.refine.browsing.EngineConfig;
 import com.google.refine.browsing.FilteredRows;
 import com.google.refine.browsing.RowVisitor;
 import com.google.refine.history.Change;
@@ -53,7 +52,7 @@ abstract public class EngineDependentMassCellOperation extends EngineDependentOp
     final protected boolean _updateRowContextDependencies;
     
     protected EngineDependentMassCellOperation(
-            JSONObject engineConfig, String columnName, boolean updateRowContextDependencies) {
+            EngineConfig engineConfig, String columnName, boolean updateRowContextDependencies) {
         super(engineConfig);
         _columnName = columnName;
         _updateRowContextDependencies = updateRowContextDependencies;

main/src/com/google/refine/operations/EngineDependentOperation.java

@@ -33,39 +33,26 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 package com.google.refine.operations;
 
-import org.json.JSONException;
-import org.json.JSONObject;
-
 import com.google.refine.browsing.Engine;
+import com.google.refine.browsing.EngineConfig;
 import com.google.refine.model.AbstractOperation;
 import com.google.refine.model.Project;
-import com.google.refine.util.ParsingUtilities;
 
 abstract public class EngineDependentOperation extends AbstractOperation {
-    final private String _engineConfigString;
     
-    transient protected JSONObject    _engineConfig;
+    transient protected EngineConfig    _engineConfig;
     
-    protected EngineDependentOperation(JSONObject engineConfig) {
+    protected EngineDependentOperation(EngineConfig engineConfig) {
         _engineConfig = engineConfig;
-        _engineConfigString = engineConfig == null || engineConfig.length() == 0
-            ? null : engineConfig.toString();
     }
     
     protected Engine createEngine(Project project) throws Exception {
         Engine engine = new Engine(project);
-        engine.initializeFromJSON(getEngineConfig());
+        engine.initializeFromConfig(getEngineConfig());
         return engine;
     }
     
-    protected JSONObject getEngineConfig() {
+    protected EngineConfig getEngineConfig() {
-        if (_engineConfig == null && _engineConfigString != null) {
-            try {
-                _engineConfig = ParsingUtilities.evaluateJsonStringToObject(_engineConfigString);
-            } catch (JSONException e) {
-                // ignore
-            }
-        }
         return _engineConfig;
     }
 }

main/src/com/google/refine/operations/cell/BlankDownOperation.java

@@ -41,6 +41,7 @@ import org.json.JSONObject;
 import org.json.JSONWriter;
 
 import com.google.refine.browsing.Engine.Mode;
+import com.google.refine.browsing.EngineConfig;
 import com.google.refine.browsing.RowVisitor;
 import com.google.refine.expr.ExpressionUtils;
 import com.google.refine.model.AbstractOperation;
@@ -58,13 +59,13 @@ public class BlankDownOperation extends EngineDependentMassCellOperation {
         JSONObject engineConfig = obj.getJSONObject("engineConfig");
         
         return new BlankDownOperation(
-            engineConfig,
+            EngineConfig.reconstruct(engineConfig),
             obj.getString("columnName")
         );
     }
     
     public BlankDownOperation(
-            JSONObject engineConfig, 
+            EngineConfig engineConfig, 
             String columnName
         ) {
         super(engineConfig, columnName, true);
@@ -77,7 +78,7 @@ public class BlankDownOperation extends EngineDependentMassCellOperation {
         writer.object();
         writer.key("op"); writer.value(OperationRegistry.s_opClassToName.get(this.getClass()));
         writer.key("description"); writer.value(getBriefDescription(null));
-        writer.key("engineConfig"); writer.value(getEngineConfig());
+        writer.key("engineConfig"); getEngineConfig().write(writer, options);
         writer.key("columnName"); writer.value(_columnName);
         writer.endObject();
     }

main/src/com/google/refine/operations/cell/FillDownOperation.java

@@ -42,6 +42,7 @@ import org.json.JSONWriter;
 
 import com.google.refine.browsing.Engine;
 import com.google.refine.browsing.Engine.Mode;
+import com.google.refine.browsing.EngineConfig;
 import com.google.refine.browsing.RowVisitor;
 import com.google.refine.expr.ExpressionUtils;
 import com.google.refine.model.AbstractOperation;
@@ -59,13 +60,13 @@ public class FillDownOperation extends EngineDependentMassCellOperation {
         JSONObject engineConfig = obj.getJSONObject("engineConfig");
         
         return new FillDownOperation(
-            engineConfig,
+            EngineConfig.reconstruct(engineConfig),
             obj.getString("columnName")
         );
     }
     
     public FillDownOperation(
-            JSONObject engineConfig, 
+            EngineConfig engineConfig, 
             String columnName
         ) {
         super(engineConfig, columnName, true);
@@ -78,7 +79,7 @@ public class FillDownOperation extends EngineDependentMassCellOperation {
         writer.object();
         writer.key("op"); writer.value(OperationRegistry.s_opClassToName.get(this.getClass()));
         writer.key("description"); writer.value(getBriefDescription(null));
-        writer.key("engineConfig"); writer.value(getEngineConfig());
+        writer.key("engineConfig"); getEngineConfig().write(writer, options);
         writer.key("columnName"); writer.value(_columnName);
         writer.endObject();
     }

main/src/com/google/refine/operations/cell/MassEditOperation.java

@@ -46,6 +46,7 @@ import org.json.JSONObject;
 import org.json.JSONWriter;
 
 import com.google.refine.Jsonizable;
+import com.google.refine.browsing.EngineConfig;
 import com.google.refine.browsing.RowVisitor;
 import com.google.refine.expr.Evaluable;
 import com.google.refine.expr.ExpressionUtils;
@@ -101,7 +102,7 @@ public class MassEditOperation extends EngineDependentMassCellOperation {
                 obj.getJSONObject("engineConfig") : null;
         
         return new MassEditOperation(
-            engineConfig,
+            EngineConfig.reconstruct(engineConfig),
             obj.getString("columnName"),
             obj.getString("expression"),
             reconstructEdits(obj.getJSONArray("edits"))
@@ -145,7 +146,7 @@ public class MassEditOperation extends EngineDependentMassCellOperation {
         return edits;
     }
     
-    public MassEditOperation(JSONObject engineConfig, String columnName, String expression, List<Edit> edits) {
+    public MassEditOperation(EngineConfig engineConfig, String columnName, String expression, List<Edit> edits) {
         super(engineConfig, columnName, true);
         _expression = expression;
         _edits = edits;
@@ -158,7 +159,7 @@ public class MassEditOperation extends EngineDependentMassCellOperation {
         writer.object();
         writer.key("op"); writer.value(OperationRegistry.s_opClassToName.get(this.getClass()));
         writer.key("description"); writer.value(getBriefDescription(null));
-        writer.key("engineConfig"); writer.value(getEngineConfig());
+        writer.key("engineConfig"); getEngineConfig().write(writer, options);
         writer.key("columnName"); writer.value(_columnName);
         writer.key("expression"); writer.value(_expression);
         writer.key("edits");

main/src/com/google/refine/operations/cell/TextTransformOperation.java

@@ -41,6 +41,7 @@ import org.json.JSONException;
 import org.json.JSONObject;
 import org.json.JSONWriter;
 
+import com.google.refine.browsing.EngineConfig;
 import com.google.refine.browsing.RowVisitor;
 import com.google.refine.expr.Evaluable;
 import com.google.refine.expr.ExpressionUtils;
@@ -66,7 +67,7 @@ public class TextTransformOperation extends EngineDependentMassCellOperation {
         JSONObject engineConfig = obj.getJSONObject("engineConfig");
         
         return new TextTransformOperation(
-            engineConfig,
+            EngineConfig.reconstruct(engineConfig),
             obj.getString("columnName"),
             obj.getString("expression"),
             stringToOnError(obj.getString("onError")),
@@ -95,7 +96,7 @@ public class TextTransformOperation extends EngineDependentMassCellOperation {
     }
     
     public TextTransformOperation(
-            JSONObject engineConfig, 
+            EngineConfig engineConfig, 
             String columnName, 
             String expression, 
             OnError onError,
@@ -116,7 +117,7 @@ public class TextTransformOperation extends EngineDependentMassCellOperation {
         writer.object();
         writer.key("op"); writer.value(OperationRegistry.s_opClassToName.get(this.getClass()));
         writer.key("description"); writer.value(getBriefDescription(null));
-        writer.key("engineConfig"); writer.value(getEngineConfig());
+        writer.key("engineConfig"); getEngineConfig().write(writer, options);
         writer.key("columnName"); writer.value(_columnName);
         writer.key("expression"); writer.value(_expression);
         writer.key("onError"); writer.value(onErrorToString(_onError));

main/src/com/google/refine/operations/column/ColumnAdditionByFetchingURLsOperation.java

@@ -42,18 +42,20 @@ import java.net.URL;
 import java.net.URLConnection;
 import java.util.ArrayList;
 import java.util.List;
-import java.util.Map;
-import java.util.HashMap;
 import java.util.Properties;
 import java.util.concurrent.TimeUnit;
-import java.util.concurrent.ExecutionException;
 
+import org.json.JSONArray;
 import org.json.JSONException;
 import org.json.JSONObject;
-import org.json.JSONArray;
 import org.json.JSONWriter;
 
+import com.google.common.cache.CacheBuilder;
+import com.google.common.cache.CacheLoader;
+import com.google.common.cache.LoadingCache;
+
 import com.google.refine.browsing.Engine;
+import com.google.refine.browsing.EngineConfig;
 import com.google.refine.browsing.FilteredRows;
 import com.google.refine.browsing.RowVisitor;
 import com.google.refine.expr.EvalError;
@@ -69,8 +71,6 @@ import com.google.refine.model.Project;
 import com.google.refine.model.Row;
 import com.google.refine.model.changes.CellAtRow;
 import com.google.refine.model.changes.ColumnAdditionChange;
-import com.google.refine.commands.HttpHeadersSupport;
-import com.google.refine.commands.HttpHeadersSupport.HttpHeaderInfo;
 import com.google.refine.operations.EngineDependentOperation;
 import com.google.refine.operations.OnError;
 import com.google.refine.operations.OperationRegistry;
@@ -78,9 +78,6 @@ import com.google.refine.operations.cell.TextTransformOperation;
 import com.google.refine.process.LongRunningProcess;
 import com.google.refine.process.Process;
 import com.google.refine.util.ParsingUtilities;
-import com.google.common.cache.CacheBuilder;
-import com.google.common.cache.LoadingCache;
-import com.google.common.cache.CacheLoader;
 
 
 public class ColumnAdditionByFetchingURLsOperation extends EngineDependentOperation {
@@ -98,7 +95,7 @@ public class ColumnAdditionByFetchingURLsOperation extends EngineDependentOperat
         JSONObject engineConfig = obj.getJSONObject("engineConfig");
 
         return new ColumnAdditionByFetchingURLsOperation(
-            engineConfig,
+            EngineConfig.reconstruct(engineConfig),
             obj.getString("baseColumnName"),
             obj.getString("urlExpression"),
             TextTransformOperation.stringToOnError(obj.getString("onError")),
@@ -111,7 +108,7 @@ public class ColumnAdditionByFetchingURLsOperation extends EngineDependentOperat
     }
 
     public ColumnAdditionByFetchingURLsOperation(
-        JSONObject     engineConfig,
+        EngineConfig   engineConfig,
         String         baseColumnName,
         String         urlExpression,
         OnError        onError,
@@ -142,7 +139,7 @@ public class ColumnAdditionByFetchingURLsOperation extends EngineDependentOperat
         writer.object();
         writer.key("op"); writer.value(OperationRegistry.s_opClassToName.get(this.getClass()));
         writer.key("description"); writer.value(getBriefDescription(null));
-        writer.key("engineConfig"); writer.value(getEngineConfig());
+        writer.key("engineConfig"); getEngineConfig().write(writer, options);
         writer.key("newColumnName"); writer.value(_newColumnName);
         writer.key("columnInsertIndex"); writer.value(_columnInsertIndex);
         writer.key("baseColumnName"); writer.value(_baseColumnName);
@@ -173,7 +170,7 @@ public class ColumnAdditionByFetchingURLsOperation extends EngineDependentOperat
     @Override
     public Process createProcess(Project project, Properties options) throws Exception {
         Engine engine = createEngine(project);
-        engine.initializeFromJSON(_engineConfig);
+        engine.initializeFromConfig(_engineConfig);
 
         Evaluable eval = MetaParser.parse(_urlExpression);
 

main/src/com/google/refine/operations/column/ColumnAdditionOperation.java

@@ -43,6 +43,7 @@ import org.json.JSONObject;
 import org.json.JSONWriter;
 
 import com.google.refine.browsing.Engine;
+import com.google.refine.browsing.EngineConfig;
 import com.google.refine.browsing.FilteredRows;
 import com.google.refine.browsing.RowVisitor;
 import com.google.refine.expr.Evaluable;
@@ -75,7 +76,7 @@ public class ColumnAdditionOperation extends EngineDependentOperation {
         JSONObject engineConfig = obj.getJSONObject("engineConfig");
         
         return new ColumnAdditionOperation(
-            engineConfig,
+            EngineConfig.reconstruct(engineConfig),
             obj.getString("baseColumnName"),
             obj.getString("expression"),
             TextTransformOperation.stringToOnError(obj.getString("onError")),
@@ -85,7 +86,7 @@ public class ColumnAdditionOperation extends EngineDependentOperation {
     }
     
     public ColumnAdditionOperation(
-        JSONObject     engineConfig,
+        EngineConfig   engineConfig,
         String         baseColumnName,
         String         expression,
         OnError        onError,
@@ -109,7 +110,7 @@ public class ColumnAdditionOperation extends EngineDependentOperation {
         writer.object();
         writer.key("op"); writer.value(OperationRegistry.s_opClassToName.get(this.getClass()));
         writer.key("description"); writer.value(getBriefDescription(null));
-        writer.key("engineConfig"); writer.value(getEngineConfig());
+        writer.key("engineConfig"); getEngineConfig().write(writer, options);
         writer.key("newColumnName"); writer.value(_newColumnName);
         writer.key("columnInsertIndex"); writer.value(_columnInsertIndex);
         writer.key("baseColumnName"); writer.value(_baseColumnName);

main/src/com/google/refine/operations/column/ColumnSplitOperation.java

@@ -45,6 +45,7 @@ import org.json.JSONObject;
 import org.json.JSONWriter;
 
 import com.google.refine.browsing.Engine;
+import com.google.refine.browsing.EngineConfig;
 import com.google.refine.browsing.FilteredRows;
 import com.google.refine.browsing.RowVisitor;
 import com.google.refine.expr.ExpressionUtils;
@@ -78,7 +79,7 @@ public class ColumnSplitOperation extends EngineDependentOperation {
         
         if ("separator".equals(mode)) {
             return new ColumnSplitOperation(
-                engineConfig,
+                EngineConfig.reconstruct(engineConfig),
                 obj.getString("columnName"),
                 obj.getBoolean("guessCellType"),
                 obj.getBoolean("removeOriginalColumn"),
@@ -88,7 +89,7 @@ public class ColumnSplitOperation extends EngineDependentOperation {
             );
         } else {
             return new ColumnSplitOperation(
-                engineConfig,
+                EngineConfig.reconstruct(engineConfig),
                 obj.getString("columnName"),
                 obj.getBoolean("guessCellType"),
                 obj.getBoolean("removeOriginalColumn"),
@@ -98,7 +99,7 @@ public class ColumnSplitOperation extends EngineDependentOperation {
     }
     
     public ColumnSplitOperation(
-        JSONObject     engineConfig,
+        EngineConfig   engineConfig,
         String         columnName,
         boolean        guessCellType,
         boolean        removeOriginalColumn,
@@ -121,7 +122,7 @@ public class ColumnSplitOperation extends EngineDependentOperation {
     }
     
     public ColumnSplitOperation(
-        JSONObject     engineConfig,
+        EngineConfig   engineConfig,
         String         columnName,
         boolean        guessCellType,
         boolean        removeOriginalColumn,
@@ -148,7 +149,7 @@ public class ColumnSplitOperation extends EngineDependentOperation {
         writer.object();
         writer.key("op"); writer.value(OperationRegistry.s_opClassToName.get(this.getClass()));
         writer.key("description"); writer.value(getBriefDescription(null));
-        writer.key("engineConfig"); writer.value(getEngineConfig());
+        writer.key("engineConfig"); getEngineConfig().write(writer, options);
         writer.key("columnName"); writer.value(_columnName);
         writer.key("guessCellType"); writer.value(_guessCellType);
         writer.key("removeOriginalColumn"); writer.value(_removeOriginalColumn);

main/src/com/google/refine/operations/recon/ExtendDataOperation.java

@@ -41,18 +41,14 @@ import java.util.Map;
 import java.util.Properties;
 import java.util.Set;
 
-import org.apache.commons.lang3.StringUtils;
 import org.json.JSONException;
 import org.json.JSONObject;
 import org.json.JSONWriter;
 
 import com.google.refine.browsing.Engine;
+import com.google.refine.browsing.EngineConfig;
 import com.google.refine.browsing.FilteredRows;
 import com.google.refine.browsing.RowVisitor;
-import com.google.refine.model.changes.DataExtensionChange;
-import com.google.refine.model.recon.ReconciledDataExtensionJob;
-import com.google.refine.model.recon.ReconciledDataExtensionJob.ColumnInfo;
-import com.google.refine.model.recon.ReconciledDataExtensionJob.DataExtension;
 import com.google.refine.history.HistoryEntry;
 import com.google.refine.model.AbstractOperation;
 import com.google.refine.model.Cell;
@@ -62,6 +58,10 @@ import com.google.refine.model.ReconCandidate;
 import com.google.refine.model.ReconType;
 import com.google.refine.model.Row;
 import com.google.refine.model.changes.CellAtRow;
+import com.google.refine.model.changes.DataExtensionChange;
+import com.google.refine.model.recon.ReconciledDataExtensionJob;
+import com.google.refine.model.recon.ReconciledDataExtensionJob.ColumnInfo;
+import com.google.refine.model.recon.ReconciledDataExtensionJob.DataExtension;
 import com.google.refine.operations.EngineDependentOperation;
 import com.google.refine.operations.OperationRegistry;
 import com.google.refine.process.LongRunningProcess;
@@ -79,7 +79,7 @@ public class ExtendDataOperation extends EngineDependentOperation {
         JSONObject engineConfig = obj.getJSONObject("engineConfig");
         
         return new ExtendDataOperation(
-            engineConfig,
+            EngineConfig.reconstruct(engineConfig),
             obj.getString("baseColumnName"),
             obj.getString("endpoint"),
             obj.getString("identifierSpace"),
@@ -90,7 +90,7 @@ public class ExtendDataOperation extends EngineDependentOperation {
     }
     
     public ExtendDataOperation(
-        JSONObject     engineConfig,
+        EngineConfig   engineConfig,
         String         baseColumnName,
         String         endpoint,
         String         identifierSpace,
@@ -115,7 +115,7 @@ public class ExtendDataOperation extends EngineDependentOperation {
         writer.object();
         writer.key("op"); writer.value(OperationRegistry.s_opClassToName.get(this.getClass()));
         writer.key("description"); writer.value(getBriefDescription(null));
-        writer.key("engineConfig"); writer.value(getEngineConfig());
+        writer.key("engineConfig"); getEngineConfig().write(writer, options);
         writer.key("columnInsertIndex"); writer.value(_columnInsertIndex);
         writer.key("baseColumnName"); writer.value(_baseColumnName);
         writer.key("endpoint"); writer.value(_endpoint);
@@ -148,14 +148,14 @@ public class ExtendDataOperation extends EngineDependentOperation {
     
     public class ExtendDataProcess extends LongRunningProcess implements Runnable {
         final protected Project     _project;
-        final protected JSONObject  _engineConfig;
+        final protected EngineConfig  _engineConfig;
         final protected long        _historyEntryID;
         protected int               _cellIndex;
         protected ReconciledDataExtensionJob _job;
 
         public ExtendDataProcess(
             Project project, 
-            JSONObject engineConfig, 
+            EngineConfig engineConfig, 
             String description
         ) throws JSONException {
             super(description);
@@ -186,7 +186,7 @@ public class ExtendDataOperation extends EngineDependentOperation {
         
         protected void populateRowsWithMatches(List<Integer> rowIndices) throws Exception {
             Engine engine = new Engine(_project);
-            engine.initializeFromJSON(_engineConfig);
+            engine.initializeFromConfig(_engineConfig);
             
             Column column = _project.columnModel.getColumnByName(_baseColumnName);
             if (column == null) {

main/src/com/google/refine/operations/recon/ReconClearSimilarCellsOperation.java

@@ -40,6 +40,7 @@ import org.json.JSONException;
 import org.json.JSONObject;
 import org.json.JSONWriter;
 
+import com.google.refine.browsing.EngineConfig;
 import com.google.refine.browsing.RowVisitor;
 import com.google.refine.history.Change;
 import com.google.refine.model.AbstractOperation;
@@ -58,14 +59,14 @@ public class ReconClearSimilarCellsOperation extends EngineDependentMassCellOper
     static public AbstractOperation reconstruct(Project project, JSONObject obj) throws Exception {
         JSONObject engineConfig = obj.getJSONObject("engineConfig");
         return new ReconClearSimilarCellsOperation(
-            engineConfig,
+            EngineConfig.reconstruct(engineConfig),
             obj.getString("columnName"),
             obj.getString("similarValue")
         );
     }
     
     public ReconClearSimilarCellsOperation(
-        JSONObject engineConfig, 
+        EngineConfig engineConfig, 
         String     columnName, 
         String     similarValue
     ) {
@@ -80,7 +81,7 @@ public class ReconClearSimilarCellsOperation extends EngineDependentMassCellOper
         writer.object();
         writer.key("op"); writer.value(OperationRegistry.s_opClassToName.get(this.getClass()));
         writer.key("description"); writer.value(getBriefDescription(null));
-        writer.key("engineConfig"); writer.value(getEngineConfig());
+        writer.key("engineConfig"); getEngineConfig().write(writer, options);
         writer.key("columnName"); writer.value(_columnName);
         writer.key("similarValue"); writer.value(_similarValue);
         

main/src/com/google/refine/operations/recon/ReconCopyAcrossColumnsOperation.java

@@ -47,6 +47,7 @@ import org.json.JSONObject;
 import org.json.JSONWriter;
 
 import com.google.refine.browsing.Engine;
+import com.google.refine.browsing.EngineConfig;
 import com.google.refine.browsing.FilteredRows;
 import com.google.refine.browsing.RowVisitor;
 import com.google.refine.history.HistoryEntry;
@@ -72,7 +73,7 @@ public class ReconCopyAcrossColumnsOperation extends EngineDependentOperation {
     static public AbstractOperation reconstruct(Project project, JSONObject obj) throws Exception {
         JSONObject engineConfig = obj.getJSONObject("engineConfig");
         return new ReconCopyAcrossColumnsOperation(
-            engineConfig, 
+            EngineConfig.reconstruct(engineConfig), 
             obj.getString("fromColumnName"),
             JSONUtilities.getStringArray(obj, "toColumnNames"),
             JSONUtilities.getStringArray(obj, "judgments"),
@@ -81,7 +82,7 @@ public class ReconCopyAcrossColumnsOperation extends EngineDependentOperation {
     }
     
     public ReconCopyAcrossColumnsOperation(
-        JSONObject engineConfig,
+        EngineConfig engineConfig,
         String fromColumnName,
         String[] toColumnNames,
         String[] judgments,
@@ -100,7 +101,7 @@ public class ReconCopyAcrossColumnsOperation extends EngineDependentOperation {
         writer.object();
         writer.key("op"); writer.value(OperationRegistry.s_opClassToName.get(this.getClass()));
         writer.key("description"); writer.value(getBriefDescription(null));
-        writer.key("engineConfig"); writer.value(getEngineConfig());
+        writer.key("engineConfig"); getEngineConfig().write(writer, options);
         writer.key("fromColumnName"); writer.value(_fromColumnName);
         writer.key("toColumnNames");
             writer.array();

main/src/com/google/refine/operations/recon/ReconDiscardJudgmentsOperation.java

@@ -42,6 +42,7 @@ import org.json.JSONException;
 import org.json.JSONObject;
 import org.json.JSONWriter;
 
+import com.google.refine.browsing.EngineConfig;
 import com.google.refine.browsing.RowVisitor;
 import com.google.refine.history.Change;
 import com.google.refine.model.AbstractOperation;
@@ -62,13 +63,13 @@ public class ReconDiscardJudgmentsOperation extends EngineDependentMassCellOpera
     static public AbstractOperation reconstruct(Project project, JSONObject obj) throws Exception {
         JSONObject engineConfig = obj.getJSONObject("engineConfig");
         return new ReconDiscardJudgmentsOperation(
-            engineConfig, 
+            EngineConfig.reconstruct(engineConfig), 
             obj.getString("columnName"),
             obj.has("clearData") && obj.getBoolean("clearData")
         );
     }
     
-    public ReconDiscardJudgmentsOperation(JSONObject engineConfig, String columnName, boolean clearData) {
+    public ReconDiscardJudgmentsOperation(EngineConfig engineConfig, String columnName, boolean clearData) {
         super(engineConfig, columnName, false);
         _clearData = clearData;
     }
@@ -80,7 +81,7 @@ public class ReconDiscardJudgmentsOperation extends EngineDependentMassCellOpera
         writer.object();
         writer.key("op"); writer.value(OperationRegistry.s_opClassToName.get(this.getClass()));
         writer.key("description"); writer.value(getBriefDescription(null));
-        writer.key("engineConfig"); writer.value(getEngineConfig());
+        writer.key("engineConfig"); getEngineConfig().write(writer, options);
         writer.key("columnName"); writer.value(_columnName);
         writer.key("clearData"); writer.value(_clearData);
         writer.endObject();

main/src/com/google/refine/operations/recon/ReconJudgeSimilarCellsOperation.java

@@ -43,6 +43,7 @@ import org.json.JSONException;
 import org.json.JSONObject;
 import org.json.JSONWriter;
 
+import com.google.refine.browsing.EngineConfig;
 import com.google.refine.browsing.RowVisitor;
 import com.google.refine.expr.ExpressionUtils;
 import com.google.refine.history.Change;
@@ -93,7 +94,7 @@ public class ReconJudgeSimilarCellsOperation extends EngineDependentMassCellOper
         }
         
         return new ReconJudgeSimilarCellsOperation(
-            engineConfig,
+            EngineConfig.reconstruct(engineConfig),
             obj.getString("columnName"),
             obj.getString("similarValue"),
             judgment,
@@ -103,7 +104,7 @@ public class ReconJudgeSimilarCellsOperation extends EngineDependentMassCellOper
     }
     
     public ReconJudgeSimilarCellsOperation(
-        JSONObject         engineConfig, 
+        EngineConfig         engineConfig, 
         String             columnName, 
         String             similarValue,
         Judgment        judgment,
@@ -124,7 +125,7 @@ public class ReconJudgeSimilarCellsOperation extends EngineDependentMassCellOper
         writer.object();
         writer.key("op"); writer.value(OperationRegistry.s_opClassToName.get(this.getClass()));
         writer.key("description"); writer.value(getBriefDescription(null));
-        writer.key("engineConfig"); writer.value(getEngineConfig());
+        writer.key("engineConfig"); getEngineConfig().write(writer, options);
         writer.key("columnName"); writer.value(_columnName);
         writer.key("similarValue"); writer.value(_similarValue);
         writer.key("judgment"); writer.value(Recon.judgmentToString(_judgment));

main/src/com/google/refine/operations/recon/ReconMarkNewTopicsOperation.java

@@ -42,6 +42,7 @@ import org.json.JSONException;
 import org.json.JSONObject;
 import org.json.JSONWriter;
 
+import com.google.refine.browsing.EngineConfig;
 import com.google.refine.browsing.RowVisitor;
 import com.google.refine.history.Change;
 import com.google.refine.model.AbstractOperation;
@@ -64,13 +65,13 @@ public class ReconMarkNewTopicsOperation extends EngineDependentMassCellOperatio
         JSONObject engineConfig = obj.getJSONObject("engineConfig");
         
         return new ReconMarkNewTopicsOperation(
-            engineConfig, 
+            EngineConfig.reconstruct(engineConfig), 
             obj.getString("columnName"),
             obj.has("shareNewTopics") ? obj.getBoolean("shareNewTopics") : false
         );
     }
 
-    public ReconMarkNewTopicsOperation(JSONObject engineConfig, String columnName, boolean shareNewTopics) {
+    public ReconMarkNewTopicsOperation(EngineConfig engineConfig, String columnName, boolean shareNewTopics) {
         super(engineConfig, columnName, false);
         _shareNewTopics = shareNewTopics;
     }
@@ -82,7 +83,7 @@ public class ReconMarkNewTopicsOperation extends EngineDependentMassCellOperatio
         writer.object();
         writer.key("op"); writer.value(OperationRegistry.s_opClassToName.get(this.getClass()));
         writer.key("description"); writer.value(getBriefDescription(null));
-        writer.key("engineConfig"); writer.value(getEngineConfig());
+        writer.key("engineConfig"); getEngineConfig().write(writer, options);
         writer.key("columnName"); writer.value(_columnName);
         writer.key("shareNewTopics"); writer.value(_shareNewTopics);
         writer.endObject();

main/src/com/google/refine/operations/recon/ReconMatchBestCandidatesOperation.java

@@ -42,6 +42,7 @@ import org.json.JSONException;
 import org.json.JSONObject;
 import org.json.JSONWriter;
 
+import com.google.refine.browsing.EngineConfig;
 import com.google.refine.browsing.RowVisitor;
 import com.google.refine.history.Change;
 import com.google.refine.model.AbstractOperation;
@@ -63,12 +64,12 @@ public class ReconMatchBestCandidatesOperation extends EngineDependentMassCellOp
         String columnName = obj.getString("columnName");
         
         return new ReconMatchBestCandidatesOperation(
-            engineConfig, 
+            EngineConfig.reconstruct(engineConfig), 
             columnName
         );
     }
     
-    public ReconMatchBestCandidatesOperation(JSONObject engineConfig, String columnName) {
+    public ReconMatchBestCandidatesOperation(EngineConfig engineConfig, String columnName) {
         super(engineConfig, columnName, false);
     }
 
@@ -79,7 +80,7 @@ public class ReconMatchBestCandidatesOperation extends EngineDependentMassCellOp
         writer.object();
         writer.key("op"); writer.value(OperationRegistry.s_opClassToName.get(this.getClass()));
         writer.key("description"); writer.value(getBriefDescription(null));
-        writer.key("engineConfig"); writer.value(getEngineConfig());
+        writer.key("engineConfig"); getEngineConfig().write(writer, options);
         writer.key("columnName"); writer.value(_columnName);
         writer.endObject();
     }

main/src/com/google/refine/operations/recon/ReconMatchSpecificTopicOperation.java

@@ -43,6 +43,7 @@ import org.json.JSONException;
 import org.json.JSONObject;
 import org.json.JSONWriter;
 
+import com.google.refine.browsing.EngineConfig;
 import com.google.refine.browsing.RowVisitor;
 import com.google.refine.history.Change;
 import com.google.refine.model.AbstractOperation;
@@ -75,7 +76,7 @@ public class ReconMatchSpecificTopicOperation extends EngineDependentMassCellOpe
         }
         
         return new ReconMatchSpecificTopicOperation(
-            engineConfig,
+            EngineConfig.reconstruct(engineConfig),
             obj.getString("columnName"),
             new ReconCandidate(
                 match.getString("id"),
@@ -89,7 +90,7 @@ public class ReconMatchSpecificTopicOperation extends EngineDependentMassCellOpe
     }
     
     public ReconMatchSpecificTopicOperation(
-        JSONObject engineConfig, 
+        EngineConfig engineConfig, 
         String columnName, 
         ReconCandidate match,
         String identifierSpace,
@@ -108,7 +109,7 @@ public class ReconMatchSpecificTopicOperation extends EngineDependentMassCellOpe
         writer.object();
         writer.key("op"); writer.value(OperationRegistry.s_opClassToName.get(this.getClass()));
         writer.key("description"); writer.value(getBriefDescription(null));
-        writer.key("engineConfig"); writer.value(getEngineConfig());
+        writer.key("engineConfig"); getEngineConfig().write(writer, options);
         writer.key("columnName"); writer.value(_columnName);
         writer.key("match");
             writer.object();

main/src/com/google/refine/operations/recon/ReconOperation.java

@@ -46,6 +46,7 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import com.google.refine.browsing.Engine;
+import com.google.refine.browsing.EngineConfig;
 import com.google.refine.browsing.FilteredRows;
 import com.google.refine.browsing.RowVisitor;
 import com.google.refine.expr.ExpressionUtils;
@@ -77,14 +78,14 @@ public class ReconOperation extends EngineDependentOperation {
         JSONObject engineConfig = obj.getJSONObject("engineConfig");
         
         return new ReconOperation(
-            engineConfig, 
+            EngineConfig.reconstruct(engineConfig), 
             obj.getString("columnName"),
             ReconConfig.reconstruct(obj.getJSONObject("config"))
         );
     }
     
     public ReconOperation(
-        JSONObject engineConfig, 
+        EngineConfig engineConfig, 
         String columnName, 
         ReconConfig reconConfig
     ) {
@@ -116,7 +117,7 @@ public class ReconOperation extends EngineDependentOperation {
         writer.key("description"); writer.value(getBriefDescription(null));
         writer.key("columnName"); writer.value(_columnName);
         writer.key("config"); _reconConfig.write(writer, options);
-        writer.key("engineConfig"); writer.value(getEngineConfig());
+        writer.key("engineConfig"); getEngineConfig().write(writer, options);
         writer.endObject();
     }
 
@@ -141,14 +142,14 @@ public class ReconOperation extends EngineDependentOperation {
     
     public class ReconProcess extends LongRunningProcess implements Runnable {
         final protected Project      _project;
-        final protected JSONObject  _engineConfig;
+        final protected EngineConfig _engineConfig;
         final protected long         _historyEntryID;
         protected List<ReconEntry>   _entries;
         protected int                _cellIndex;
         
         public ReconProcess(
             Project project, 
-            JSONObject engineConfig, 
+            EngineConfig engineConfig, 
             String description
         ) {
             super(description);
@@ -208,7 +209,7 @@ public class ReconOperation extends EngineDependentOperation {
         
         protected void populateEntries() throws Exception {
             Engine engine = new Engine(_project);
-            engine.initializeFromJSON(_engineConfig);
+            engine.initializeFromConfig(_engineConfig);
             
             Column column = _project.columnModel.getColumnByName(_columnName);
             if (column == null) {

main/src/com/google/refine/operations/row/RowFlagOperation.java

@@ -42,6 +42,7 @@ import org.json.JSONObject;
 import org.json.JSONWriter;
 
 import com.google.refine.browsing.Engine;
+import com.google.refine.browsing.EngineConfig;
 import com.google.refine.browsing.FilteredRows;
 import com.google.refine.browsing.RowVisitor;
 import com.google.refine.history.Change;
@@ -62,12 +63,12 @@ public class RowFlagOperation extends EngineDependentOperation {
         boolean flagged = obj.getBoolean("flagged");
         
         return new RowFlagOperation(
-            engineConfig, 
+            EngineConfig.reconstruct(engineConfig),
             flagged
         );
     }
     
-    public RowFlagOperation(JSONObject engineConfig, boolean flagged) {
+    public RowFlagOperation(EngineConfig engineConfig, boolean flagged) {
         super(engineConfig);
         _flagged = flagged;
     }
@@ -79,7 +80,7 @@ public class RowFlagOperation extends EngineDependentOperation {
         writer.object();
         writer.key("op"); writer.value(OperationRegistry.s_opClassToName.get(this.getClass()));
         writer.key("description"); writer.value(getBriefDescription(null));
-        writer.key("engineConfig"); writer.value(getEngineConfig());
+        writer.key("engineConfig"); getEngineConfig().write(writer, options);
         writer.key("flagged"); writer.value(_flagged);
         writer.endObject();
     }

main/src/com/google/refine/operations/row/RowRemovalOperation.java

@@ -42,6 +42,7 @@ import org.json.JSONObject;
 import org.json.JSONWriter;
 
 import com.google.refine.browsing.Engine;
+import com.google.refine.browsing.EngineConfig;
 import com.google.refine.browsing.FilteredRows;
 import com.google.refine.browsing.RowVisitor;
 import com.google.refine.history.HistoryEntry;
@@ -57,11 +58,11 @@ public class RowRemovalOperation extends EngineDependentOperation {
         JSONObject engineConfig = obj.getJSONObject("engineConfig");
         
         return new RowRemovalOperation(
-            engineConfig
+            EngineConfig.reconstruct(engineConfig)
         );
     }
     
-    public RowRemovalOperation(JSONObject engineConfig) {
+    public RowRemovalOperation(EngineConfig engineConfig) {
         super(engineConfig);
     }
 
@@ -72,7 +73,7 @@ public class RowRemovalOperation extends EngineDependentOperation {
         writer.object();
         writer.key("op"); writer.value(OperationRegistry.s_opClassToName.get(this.getClass()));
         writer.key("description"); writer.value(getBriefDescription(null));
-        writer.key("engineConfig"); writer.value(getEngineConfig());
+        writer.key("engineConfig"); getEngineConfig().write(writer, options);
         writer.endObject();
     }
 

main/src/com/google/refine/operations/row/RowStarOperation.java

@@ -42,6 +42,7 @@ import org.json.JSONObject;
 import org.json.JSONWriter;
 
 import com.google.refine.browsing.Engine;
+import com.google.refine.browsing.EngineConfig;
 import com.google.refine.browsing.FilteredRows;
 import com.google.refine.browsing.RowVisitor;
 import com.google.refine.history.Change;
@@ -62,12 +63,12 @@ public class RowStarOperation extends EngineDependentOperation {
         boolean starred = obj.getBoolean("starred");
         
         return new RowStarOperation(
-            engineConfig, 
+            EngineConfig.reconstruct(engineConfig), 
             starred
         );
     }
     
-    public RowStarOperation(JSONObject engineConfig, boolean starred) {
+    public RowStarOperation(EngineConfig engineConfig, boolean starred) {
         super(engineConfig);
         _starred = starred;
     }
@@ -79,7 +80,7 @@ public class RowStarOperation extends EngineDependentOperation {
         writer.object();
         writer.key("op"); writer.value(OperationRegistry.s_opClassToName.get(this.getClass()));
         writer.key("description"); writer.value(getBriefDescription(null));
-        writer.key("engineConfig"); writer.value(getEngineConfig());
+        writer.key("engineConfig"); getEngineConfig().write(writer, options);
         writer.key("starred"); writer.value(_starred);
         writer.endObject();
     }

main/tests/server/src/com/google/refine/expr/EvalErrorTests.java

@@ -7,7 +7,7 @@ import com.google.refine.tests.util.TestUtils;
 public class EvalErrorTests {
     @Test
     public void serializeEvalError() {
-        EvalError e = new EvalError("this is a critical error");
+        EvalError e = new EvalError("This is a critical error");
         TestUtils.isSerializedTo(e, "{\"type\":\"error\",\"message\":\"This is a critical error\"}");
     }
 }

main/tests/server/src/com/google/refine/tests/browsing/EngineTests.java

@@ -7,8 +7,6 @@ import com.google.refine.browsing.Engine;
 import com.google.refine.model.Project;
 import com.google.refine.tests.util.TestUtils;
 
-// TODO Engine and engine config should be separated
-// create an EngineConfig class that can be used in operations directly (to avoid manipulating JSONObject)
 
 public class EngineTests {
     @Test

main/tests/server/src/com/google/refine/tests/browsing/facets/EngineConfigTests.java

@@ -0,0 +1,62 @@
+package com.google.refine.tests.browsing.facets;
+
+import org.json.JSONObject;
+import org.testng.Assert;
+import org.testng.annotations.Test;
+
+import com.google.refine.browsing.EngineConfig;
+import com.google.refine.browsing.Engine.Mode;
+import com.google.refine.tests.util.TestUtils;
+
+public class EngineConfigTests {
+    
+    public static String engineConfigJson =
+              "{\n"
+            + "      \"mode\": \"row-based\",\n"
+            + "      \"facets\": [\n"
+            + "        {\n"
+            + "          \"mode\": \"text\",\n"
+            + "          \"invert\": false,\n"
+            + "          \"caseSensitive\": false,\n"
+            + "          \"query\": \"www\",\n"
+            + "          \"name\": \"reference\",\n"
+            + "          \"type\": \"text\",\n"
+            + "          \"columnName\": \"reference\"\n"
+            + "        }\n"
+            + "      ]\n"
+            + "    }";
+    
+    public static String engineConfigRecordModeJson =
+             "{"
+            + "    \"mode\":\"record-based\","
+            + "    \"facets\":[]"
+            + "}";
+    
+    public static String noFacetProvided = "{\"mode\":\"row-based\"}";
+    
+    @Test
+    public void serializeEngineConfig() {
+        EngineConfig ec = EngineConfig.reconstruct(new JSONObject(engineConfigJson));
+        TestUtils.isSerializedTo(ec, engineConfigJson);
+    }
+    
+    @Test
+    public void serializeEngineConfigRecordMode() {
+        EngineConfig ec = EngineConfig.reconstruct(new JSONObject(engineConfigRecordModeJson));
+        TestUtils.isSerializedTo(ec, engineConfigRecordModeJson);
+    }
+    
+    @Test
+    public void reconstructNullEngineConfig() {
+        EngineConfig ec = EngineConfig.reconstruct(null);
+        Assert.assertEquals(ec.getMode(), Mode.RowBased);
+        Assert.assertTrue(ec.getFacetConfigs().isEmpty());
+    }
+    
+    @Test
+    public void reconstructNoFacetsProvided() {
+        EngineConfig ec = EngineConfig.reconstruct(new JSONObject(noFacetProvided));
+        Assert.assertEquals(ec.getMode(), Mode.RowBased);
+        Assert.assertTrue(ec.getFacetConfigs().isEmpty());
+    }
+}

main/tests/server/src/com/google/refine/tests/browsing/facets/ListFacetTests.java

@@ -0,0 +1,80 @@
+package com.google.refine.tests.browsing.facets;
+
+import org.json.JSONObject;
+import org.testng.annotations.Test;
+
+import com.google.refine.browsing.Engine;
+import com.google.refine.browsing.facets.Facet;
+import com.google.refine.browsing.facets.ListFacet.ListFacetConfig;
+import com.google.refine.model.Project;
+import com.google.refine.tests.RefineTest;
+import com.google.refine.tests.util.TestUtils;
+
+public class ListFacetTests extends RefineTest {
+    
+    private static String jsonConfig = "{"
+            + "\"type\":\"list\","
+            + "\"name\":\"facet A\","
+            + "\"columnName\":\"Column A\","
+            + "\"expression\":\"value+\\\"bar\\\"\","
+            + "\"omitBlank\":false,"
+            + "\"omitError\":false,"
+            + "\"selection\":[{\"v\":{\"v\":\"foobar\",\"l\":\"true\"}}],"
+            + "\"selectBlank\":false,"
+            + "\"selectError\":false,"
+            + "\"invert\":false"
+            + "}";
+    
+    private static String jsonFacetError = "{"
+            + "\"name\":\"facet A\","
+            + "\"expression\":\"value+\\\"bar\\\"\","
+            + "\"columnName\":\"Column A\","
+            + "\"invert\":false,"
+            + "\"error\":\"No column named Column A\"}\" are not equal as JSON strings.\n" + 
+            "}";
+    
+    private static String jsonFacet = "{"
+            + "\"name\":\"facet A\","
+            + "\"expression\":\"value+\\\"bar\\\"\","
+            + "\"columnName\":\"Column A\","
+            + "\"invert\":false,"
+            + "\"choices\":["
+            + "     {\"v\":{\"v\":\"foobar\",\"l\":\"foobar\"},\"c\":1,\"s\":true},"
+            + "     {\"v\":{\"v\":\"barbar\",\"l\":\"barbar\"},\"c\":1,\"s\":false}"
+            + "]}";
+
+    @Test
+    public void serializeListFacetConfig() {
+        ListFacetConfig facetConfig = new ListFacetConfig();
+        facetConfig.initializeFromJSON(new JSONObject(jsonConfig));
+        TestUtils.isSerializedTo(facetConfig, jsonConfig);
+    }
+    
+    @Test
+    public void serializeListFacet() {
+        Project project = createCSVProject("Column A\n" +
+                "foo\n" +
+                "bar\n");
+        Engine engine = new Engine(project);
+        
+        ListFacetConfig facetConfig = new ListFacetConfig();
+        facetConfig.initializeFromJSON(new JSONObject(jsonConfig));
+        
+        Facet facet = facetConfig.apply(project);
+        facet.computeChoices(project, engine.getAllFilteredRows());
+        
+        TestUtils.isSerializedTo(facet, jsonFacet);
+    }
+    
+    @Test
+    public void serializeListFacetWithError() {
+        Project project = createCSVProject("other column\n" +
+                "foo\n" +
+                "bar\n");
+       
+        ListFacetConfig facetConfig = new ListFacetConfig();
+        facetConfig.initializeFromJSON(new JSONObject(jsonConfig));
+        Facet facet = facetConfig.apply(project);
+        TestUtils.isSerializedTo(facet, jsonFacetError);
+    }
+}

main/tests/server/src/com/google/refine/tests/browsing/facets/RangeFacetTests.java

@@ -0,0 +1,72 @@
+package com.google.refine.tests.browsing.facets;
+
+import org.json.JSONObject;
+import org.testng.annotations.Test;
+
+import com.google.refine.browsing.Engine;
+import com.google.refine.browsing.facets.RangeFacet;
+import com.google.refine.browsing.facets.RangeFacet.RangeFacetConfig;
+import com.google.refine.model.Cell;
+import com.google.refine.model.Project;
+import com.google.refine.tests.RefineTest;
+import com.google.refine.tests.util.TestUtils;
+
+public class RangeFacetTests extends RefineTest {
+    public static String configJson = "{\n" + 
+            "          \"selectNumeric\": true,\n" + 
+            "          \"expression\": \"value\",\n" + 
+            "          \"selectBlank\": true,\n" + 
+            "          \"selectNonNumeric\": true,\n" + 
+            "          \"selectError\": true,\n" + 
+            "          \"name\": \"my column\",\n" + 
+            "          \"from\": -30,\n" + 
+            "          \"to\": 90,\n" + 
+            "          \"type\": \"range\",\n" + 
+            "          \"columnName\": \"my column\"\n" + 
+            "        }";
+    
+    public static String facetJson = "{"
+            + "\"name\":\"my column\","
+            + "\"expression\":\"value\","
+            + "\"columnName\":\"my column\","
+            + "\"min\":-50,"
+            + "\"max\":90,"
+            + "\"step\":10,"
+            + "\"bins\":[1,0,0,0,0,1,0,0,0,0,0,0,0,1],"
+            + "\"baseBins\":[1,0,0,0,0,1,0,0,0,0,0,0,0,1],"
+            + "\"from\":-30,"
+            + "\"to\":90,"
+            + "\"baseNumericCount\":3,"
+            + "\"baseNonNumericCount\":1,"
+            + "\"baseBlankCount\":0,"
+            + "\"baseErrorCount\":0,"
+            + "\"numericCount\":3,"
+            + "\"nonNumericCount\":1,"
+            + "\"blankCount\":0,"
+            + "\"errorCount\":0}";
+    
+    @Test
+    public void serializeRangeFacetConfig() {
+        RangeFacetConfig config = new RangeFacetConfig();
+        config.initializeFromJSON(new JSONObject(configJson));
+        TestUtils.isSerializedTo(config, configJson);
+    }
+    
+    @Test
+    public void serializeRangeFacet() {
+        Project project = createCSVProject("my column\n"
+                + "89.2\n"
+                + "-45.9\n"
+                + "blah\n"
+                + "0.4\n");
+        project.rows.get(0).cells.set(0, new Cell(89.2, null));
+        project.rows.get(1).cells.set(0, new Cell(-45.9, null));
+        project.rows.get(3).cells.set(0, new Cell(0.4, null));
+        Engine engine = new Engine(project);
+        RangeFacetConfig config = new RangeFacetConfig();
+        config.initializeFromJSON(new JSONObject(configJson));
+        RangeFacet facet = config.apply(project);
+        facet.computeChoices(project, engine.getAllFilteredRows());
+        TestUtils.isSerializedTo(facet, facetJson);
+    }
+}

main/tests/server/src/com/google/refine/tests/browsing/facets/ScatterplotFacetTests.java

@@ -0,0 +1,80 @@
+package com.google.refine.tests.browsing.facets;
+
+import org.json.JSONObject;
+import org.testng.annotations.Test;
+
+import com.google.refine.browsing.Engine;
+import com.google.refine.browsing.facets.ScatterplotFacet;
+import com.google.refine.browsing.facets.ScatterplotFacet.ScatterplotFacetConfig;
+import com.google.refine.model.Cell;
+import com.google.refine.model.Project;
+import com.google.refine.tests.RefineTest;
+import com.google.refine.tests.util.TestUtils;
+
+public class ScatterplotFacetTests extends RefineTest {
+    public static String configJson = "{\n" + 
+            "          \"to_x\": 1,\n" + 
+            "          \"to_y\": 1,\n" + 
+            "          \"dot\": 1,\n" + 
+            "          \"from_x\": 0.21333333333333335,\n" + 
+            "          \"l\": 150,\n" + 
+            "          \"type\": \"scatterplot\",\n" + 
+            "          \"from_y\": 0.26666666666666666,\n" + 
+            "          \"dim_y\": \"lin\",\n" + 
+            "          \"ex\": \"value\",\n" + 
+            "          \"dim_x\": \"lin\",\n" +
+            "          \"ey\": \"value\",\n" + 
+            "          \"cx\": \"my column\",\n" + 
+            "          \"cy\": \"e\",\n" + 
+            "          \"name\": \"my column (x) vs. e (y)\"\n" + 
+            "        }";
+    
+    public static String facetJson = "{"
+            + "\"name\":\"my column (x) vs. e (y)\","
+            + "\"cx\":\"my column\","
+            + "\"ex\":\"value\","
+            + "\"cy\":\"e\","
+            + "\"ey\":\"value\","
+            + "\"l\":150,"
+            + "\"dot\":1,"
+            + "\"r\":0,"
+            + "\"dim_x\":0,"
+            + "\"dim_y\":0,"
+            + "\"color\":\"000000\","
+            + "\"from_x\":0.21333333333333335,"
+            + "\"to_x\":1,"
+            + "\"from_y\":0.26666666666666666,"
+            + "\"to_y\":1"
+            + "}";
+    
+    @Test
+    public void serializeScatterplotFacetConfig() {
+        ScatterplotFacetConfig config = new ScatterplotFacetConfig();
+        config.initializeFromJSON(new JSONObject(configJson));
+        TestUtils.isSerializedTo(config, configJson);
+    }
+    
+    @Test
+    public void serializeScatterplotFacet() {
+        Project project = createCSVProject("my column,e\n"
+                + "89.2,89.2\n" + 
+                "-45.9,-45.9\n" + 
+                "blah,blah\n" + 
+                "0.4,0.4\n");
+        Engine engine = new Engine(project);
+        project.rows.get(0).cells.set(0, new Cell(89.2, null));
+        project.rows.get(0).cells.set(1, new Cell(89.2, null));
+        project.rows.get(1).cells.set(0, new Cell(-45.9, null));
+        project.rows.get(1).cells.set(1, new Cell(-45.9, null));
+        project.rows.get(3).cells.set(0, new Cell(0.4, null));
+        project.rows.get(3).cells.set(1, new Cell(0.4, null));
+        
+        ScatterplotFacetConfig config = new ScatterplotFacetConfig();
+        config.initializeFromJSON(new JSONObject(configJson));
+        
+        ScatterplotFacet facet = config.apply(project);
+        facet.computeChoices(project, engine.getAllFilteredRows());
+        
+        TestUtils.isSerializedTo(facet, facetJson);
+    }
+}

main/tests/server/src/com/google/refine/tests/browsing/facets/TextSearchFacetTests.java

@@ -43,20 +43,35 @@ import org.testng.annotations.BeforeMethod;
 import org.testng.annotations.BeforeTest;
 import org.testng.annotations.Test;
 
-import com.google.refine.model.ModelException;
-import com.google.refine.model.Project;
-import com.google.refine.model.metadata.ProjectMetadata;
 import com.google.refine.browsing.RowFilter;
 import com.google.refine.browsing.facets.TextSearchFacet;
+import com.google.refine.browsing.facets.TextSearchFacet.TextSearchFacetConfig;
+import com.google.refine.model.ModelException;
+import com.google.refine.model.Project;
 import com.google.refine.tests.RefineTest;
+import com.google.refine.tests.util.TestUtils;
 
 
 public class TextSearchFacetTests extends RefineTest {
     // dependencies
     private Project project;
+    private TextSearchFacetConfig textfilterconfig;
     private TextSearchFacet textfilter;
     private RowFilter rowfilter;
-    private JSONObject textsearchfacet;
+    private String sensitiveConfigJson = "{\"type\":\"text\","
+            + "\"name\":\"Value\","
+            + "\"columnName\":\"Value\","
+            + "\"mode\":\"text\","
+            + "\"caseSensitive\":true,"
+            + "\"invert\":false,"
+            + "\"query\":\"A\"}";
+    
+    private String sensitiveFacetJson = "{\"name\":\"Value\","
+            + "\"columnName\":\"Value\","
+            + "\"query\":\"A\","
+            + "\"mode\":\"text\","
+            + "\"caseSensitive\":true,"
+            + "\"invert\":false}";
 
     @Override
     @BeforeTest
@@ -74,6 +89,14 @@ public class TextSearchFacetTests extends RefineTest {
             + "Abc\n");
     }
     
+    private void configureFilter(String filter) {
+        //Add the facet to the project and create a row filter
+        textfilterconfig = new TextSearchFacetConfig();
+        textfilterconfig.initializeFromJSON(new JSONObject(filter));
+        textfilter = textfilterconfig.apply(project);
+        rowfilter = textfilter.getRowFilter(project);
+    }
+    
     /**
      * Test to demonstrate the intended behaviour of the function
      */
@@ -95,11 +118,7 @@ public class TextSearchFacetTests extends RefineTest {
                             + "\"invert\":false,"
                             + "\"query\":\"a\"}";
         
-        //Add the facet to the project and create a row filter
+        configureFilter(filter);
-        textfilter = new TextSearchFacet();
-        textsearchfacet = new JSONObject(filter);
-        textfilter.initializeFromJSON(project,textsearchfacet);
-        rowfilter = textfilter.getRowFilter(project);
 
         //Check each row in the project against the filter
         Assert.assertEquals(rowfilter.filterRow(project, 0, project.rows.get(0)),true);
@@ -125,11 +144,7 @@ public class TextSearchFacetTests extends RefineTest {
                             + "\"invert\":true,"
                             + "\"query\":\"a\"}";
         
-        //Add the facet to the project and create a row filter
+        configureFilter(filter);
-        textfilter = new TextSearchFacet();
-        textsearchfacet = new JSONObject(filter);
-        textfilter.initializeFromJSON(project,textsearchfacet);
-        rowfilter = textfilter.getRowFilter(project);
 
         //Check each row in the project against the filter
         Assert.assertEquals(rowfilter.filterRow(project, 0, project.rows.get(0)),false);
@@ -155,11 +170,7 @@ public class TextSearchFacetTests extends RefineTest {
                             + "\"invert\":false,"
                             + "\"query\":\"[bc]\"}";
         
-        //Add the facet to the project and create a row filter
+        configureFilter(filter);
-        textfilter = new TextSearchFacet();
-        textsearchfacet = new JSONObject(filter);
-        textfilter.initializeFromJSON(project,textsearchfacet);
-        rowfilter = textfilter.getRowFilter(project);
 
         //Check each row in the project against the filter
         Assert.assertEquals(rowfilter.filterRow(project, 0, project.rows.get(0)),false);
@@ -172,24 +183,7 @@ public class TextSearchFacetTests extends RefineTest {
     public void testCaseSensitiveFilter() throws Exception {
         //Apply case-sensitive filter "A"
         
-        //Column: "Value"
+        configureFilter(sensitiveConfigJson);
-        //Filter Query: "A"
-        //Mode: "text"
-        //Case sensitive: True
-        //Invert: False
-        String filter =     "{\"type\":\"text\","
-                            + "\"name\":\"Value\","
-                            + "\"columnName\":\"Value\","
-                            + "\"mode\":\"text\","
-                            + "\"caseSensitive\":true,"
-                            + "\"invert\":false,"
-                            + "\"query\":\"A\"}";
-
-        //Add the facet to the project and create a row filter
-        textfilter = new TextSearchFacet();
-        textsearchfacet = new JSONObject(filter);
-        textfilter.initializeFromJSON(project,textsearchfacet);
-        rowfilter = textfilter.getRowFilter(project);
 
         //Check each row in the project against the filter
         //Expect to retrieve one row containing "Abc"
@@ -198,5 +192,20 @@ public class TextSearchFacetTests extends RefineTest {
         Assert.assertEquals(rowfilter.filterRow(project, 2, project.rows.get(2)),false);
         Assert.assertEquals(rowfilter.filterRow(project, 3, project.rows.get(3)),true);
     }
+    
+    @Test
+    public void serializeTextSearchFacetConfig() {
+        TextSearchFacetConfig config = new TextSearchFacetConfig();
+        config.initializeFromJSON(new JSONObject(sensitiveConfigJson));
+        TestUtils.isSerializedTo(config, sensitiveConfigJson);
+    }
+    
+    @Test
+    public void serializeTextSearchFacet() {
+        TextSearchFacetConfig config = new TextSearchFacetConfig();
+        config.initializeFromJSON(new JSONObject(sensitiveConfigJson));
+        TextSearchFacet facet = config.apply(project);
+        TestUtils.isSerializedTo(facet, sensitiveFacetJson);
+    }
 }
 

main/tests/server/src/com/google/refine/tests/browsing/facets/TimeRangeFacetTests.java

@@ -0,0 +1,77 @@
+package com.google.refine.tests.browsing.facets;
+
+import java.time.OffsetDateTime;
+
+import org.json.JSONObject;
+import org.testng.annotations.Test;
+
+import com.google.refine.browsing.Engine;
+import com.google.refine.browsing.facets.TimeRangeFacet;
+import com.google.refine.browsing.facets.TimeRangeFacet.TimeRangeFacetConfig;
+import com.google.refine.model.Cell;
+import com.google.refine.model.Project;
+import com.google.refine.tests.RefineTest;
+import com.google.refine.tests.util.TestUtils;
+
+
+public class TimeRangeFacetTests extends RefineTest {
+    
+    public static String facetJson = "{"
+            + "\"name\":\"my column\","
+            + "\"expression\":\"value\","
+            + "\"columnName\":\"my column\","
+            + "\"min\":1.199329445E12,"
+            + "\"max\":1.51496695E12,"
+            + "\"step\":3.1556952E10,"
+            + "\"bins\":[1,0,0,0,1,0,0,0,0,0,1],"
+            + "\"baseBins\":[1,0,0,0,1,0,0,0,0,0,1],"
+            + "\"from\":1.262443349E12,"
+            + "\"to\":1.51496695E12,"
+            + "\"baseTimeCount\":3,"
+            + "\"baseNonTimeCount\":1,"
+            + "\"baseBlankCount\":0,"
+            + "\"baseErrorCount\":0,"
+            + "\"timeCount\":3,"
+            + "\"nonTimeCount\":1,"
+            + "\"blankCount\":0,"
+            + "\"errorCount\":0}";
+    
+    public static String configJson = "{\n" + 
+            "          \"selectNonTime\": true,\n" + 
+            "          \"expression\": \"value\",\n" + 
+            "          \"selectBlank\": true,\n" + 
+            "          \"selectError\": true,\n" + 
+            "          \"selectTime\": true,\n" + 
+            "          \"name\": \"my column\",\n" + 
+            "          \"from\": 1262443349000,\n" + 
+            "          \"to\": 1514966950000,\n" + 
+            "          \"type\": \"timerange\",\n" + 
+            "          \"columnName\": \"my column\"\n" + 
+            "        }";
+    
+    @Test
+    public void serializeTimeRangeFacetConfig() {
+        TimeRangeFacetConfig config = new TimeRangeFacetConfig();
+        config.initializeFromJSON(new JSONObject(configJson));
+        TestUtils.isSerializedTo(config, configJson);
+    }
+    
+    @Test
+    public void serializeTimeRangeFacet() {
+        Project project = createCSVProject("my column\n"
+                + "placeholder\n"
+                + "nontime\n"
+                + "placeholder\n"
+                + "placeholder\n");
+        project.rows.get(0).cells.set(0, new Cell(OffsetDateTime.parse("2018-01-03T08:09:10Z"), null));
+        project.rows.get(2).cells.set(0, new Cell(OffsetDateTime.parse("2008-01-03T03:04:05Z"), null));
+        project.rows.get(3).cells.set(0, new Cell(OffsetDateTime.parse("2012-04-05T02:00:01Z"), null));
+        
+        Engine engine = new Engine(project);
+        TimeRangeFacetConfig config = new TimeRangeFacetConfig();
+        config.initializeFromJSON(new JSONObject(configJson));
+        TimeRangeFacet facet = config.apply(project);
+        facet.computeChoices(project, engine.getAllFilteredRows());
+        TestUtils.isSerializedTo(facet, facetJson);
+    }
+}

main/tests/server/src/com/google/refine/tests/commands/CommandStub.java

@@ -40,6 +40,7 @@ import org.json.JSONException;
 import org.json.JSONObject;
 
 import com.google.refine.browsing.Engine;
+import com.google.refine.browsing.EngineConfig;
 import com.google.refine.commands.Command;
 import com.google.refine.model.Project;
 
@@ -53,7 +54,7 @@ public class CommandStub extends Command {
         return getProject(request);
     }
 
-    public JSONObject wrapGetEngineConfig(HttpServletRequest request)
+    public EngineConfig wrapGetEngineConfig(HttpServletRequest request)
     throws JSONException {
         return getEngineConfig(request);
     }

main/tests/server/src/com/google/refine/tests/commands/CommandTests.java

@@ -52,6 +52,8 @@ import org.testng.annotations.Test;
 
 import com.google.refine.ProjectManager;
 import com.google.refine.browsing.Engine;
+import com.google.refine.browsing.Engine.Mode;
+import com.google.refine.browsing.EngineConfig;
 import com.google.refine.model.Project;
 import com.google.refine.tests.RefineTest;
 
@@ -151,11 +153,11 @@ public class CommandTests extends RefineTest {
 
     @Test
     public void getEngineConfigRegressionTest() {
-        when(request.getParameter("engine")).thenReturn("{\"hello\":\"world\"}");
+        when(request.getParameter("engine")).thenReturn("{\"mode\":\"row-based\"}");
-        JSONObject o = null;
+        EngineConfig o = null;
         try {
             o = SUT.wrapGetEngineConfig(request);
-            Assert.assertEquals("world", o.getString("hello"));
+            Assert.assertEquals(Mode.RowBased, o.getMode());
         } catch (JSONException e) {
             Assert.fail();
         } catch (Exception e) {

main/tests/server/src/com/google/refine/tests/model/CacheTests.java

@@ -45,6 +45,7 @@ import org.testng.annotations.BeforeTest;
 import org.testng.annotations.Test;
 
 import com.google.refine.browsing.Engine;
+import com.google.refine.browsing.EngineConfig;
 import com.google.refine.browsing.RowVisitor;
 import com.google.refine.expr.functions.FacetCount;
 import com.google.refine.grel.Function;
@@ -72,7 +73,7 @@ public class CacheTests extends RefineTest {
     // dependencies
     Project project;
     Properties options;
-    JSONObject engine_config;
+    EngineConfig engine_config;
     Engine engine;
     Properties bindings;
 
@@ -81,8 +82,8 @@ public class CacheTests extends RefineTest {
         project = createProjectWithColumns("CacheTests", "Column A");
         
         engine = new Engine(project);
-        engine_config = new JSONObject(ENGINE_JSON_DUPLICATES);
+        engine_config = EngineConfig.reconstruct(new JSONObject(ENGINE_JSON_DUPLICATES));
-        engine.initializeFromJSON(engine_config);
+        engine.initializeFromConfig(engine_config);
         engine.setMode(Engine.Mode.RowBased);
         
         bindings = new Properties();

main/tests/server/src/com/google/refine/tests/operations/cell/BlankDownTests.java

@@ -11,6 +11,7 @@ import org.testng.annotations.BeforeSuite;
 import org.testng.annotations.Test;
 
 import com.google.refine.ProjectManager;
+import com.google.refine.browsing.EngineConfig;
 import com.google.refine.model.AbstractOperation;
 import com.google.refine.model.Project;
 import com.google.refine.operations.OperationRegistry;
@@ -56,7 +57,7 @@ public class BlankDownTests extends RefineTest {
     @Test
     public void testBlankDownRecords() throws Exception {
         AbstractOperation op = new BlankDownOperation(
-                new JSONObject("{\"mode\":\"record-based\",\"facets\":[]}"),
+                EngineConfig.reconstruct(new JSONObject("{\"mode\":\"record-based\",\"facets\":[]}")),
                 "second");
         Process process = op.createProcess(project, new Properties());
         process.performImmediate();
@@ -70,7 +71,7 @@ public class BlankDownTests extends RefineTest {
     @Test
     public void testBlankDownRows() throws Exception {
         AbstractOperation op = new BlankDownOperation(
-                new JSONObject("{\"mode\":\"row-based\",\"facets\":[]}"),
+                EngineConfig.reconstruct(new JSONObject("{\"mode\":\"row-based\",\"facets\":[]}")),
                 "second");
         Process process = op.createProcess(project, new Properties());
         process.performImmediate();

main/tests/server/src/com/google/refine/tests/operations/cell/FillDownTests.java

@@ -11,6 +11,7 @@ import org.testng.annotations.BeforeSuite;
 import org.testng.annotations.Test;
 
 import com.google.refine.ProjectManager;
+import com.google.refine.browsing.EngineConfig;
 import com.google.refine.model.AbstractOperation;
 import com.google.refine.model.Project;
 import com.google.refine.operations.OperationRegistry;
@@ -55,7 +56,7 @@ public class FillDownTests extends RefineTest {
     @Test
     public void testFillDownRecordKey() throws Exception {
         AbstractOperation op = new FillDownOperation(
-                new JSONObject("{\"mode\":\"record-based\",\"facets\":[]}"),
+                EngineConfig.reconstruct(new JSONObject("{\"mode\":\"record-based\",\"facets\":[]}")),
                 "key");
         Process process = op.createProcess(project, new Properties());
         process.performImmediate();
@@ -71,7 +72,7 @@ public class FillDownTests extends RefineTest {
     @Test
     public void testFillDownRecords() throws Exception {
         AbstractOperation op = new FillDownOperation(
-                new JSONObject("{\"mode\":\"record-based\",\"facets\":[]}"),
+                EngineConfig.reconstruct(new JSONObject("{\"mode\":\"record-based\",\"facets\":[]}")),
                 "second");
         Process process = op.createProcess(project, new Properties());
         process.performImmediate();
@@ -87,7 +88,7 @@ public class FillDownTests extends RefineTest {
     @Test
     public void testFillDownRows() throws Exception {       
         AbstractOperation op = new FillDownOperation(
-                new JSONObject("{\"mode\":\"row-based\",\"facets\":[]}"),
+                EngineConfig.reconstruct(new JSONObject("{\"mode\":\"row-based\",\"facets\":[]}")),
                 "second");
         Process process = op.createProcess(project, new Properties());
         process.performImmediate();

main/tests/server/src/com/google/refine/tests/operations/column/ColumnAdditionByFetchingURLsOperationTests.java

@@ -46,6 +46,7 @@ import org.testng.annotations.BeforeMethod;
 import org.testng.annotations.BeforeTest;
 import org.testng.annotations.Test;
 
+import com.google.refine.browsing.EngineConfig;
 import com.google.refine.expr.ExpressionUtils;
 import com.google.refine.model.Cell;
 import com.google.refine.model.ModelException;
@@ -63,7 +64,7 @@ import com.google.refine.tests.util.TestUtils;
 
 public class ColumnAdditionByFetchingURLsOperationTests extends RefineTest {
 
-    static final String ENGINE_JSON_URLS = "{\"mode\":\"row-based\"}}";
+    static final String ENGINE_JSON_URLS = "{\"mode\":\"row-based\"}";
 
     @Override
     @BeforeTest
@@ -75,7 +76,7 @@ public class ColumnAdditionByFetchingURLsOperationTests extends RefineTest {
     // dependencies
     private Project project;
     private Properties options;
-    private JSONObject engine_config;
+    private EngineConfig engine_config = EngineConfig.reconstruct(new JSONObject(ENGINE_JSON_URLS));
 
     @BeforeMethod
     public void SetUp() throws JSONException, IOException, ModelException {

main/tests/server/src/com/google/refine/tests/operations/recon/ExtendDataOperationTests.java

@@ -50,6 +50,7 @@ import org.testng.annotations.BeforeTest;
 import org.testng.annotations.Test;
 
 import com.google.refine.browsing.Engine;
+import com.google.refine.browsing.EngineConfig;
 import com.google.refine.model.Cell;
 import com.google.refine.model.ModelException;
 import com.google.refine.model.Project;
@@ -81,7 +82,7 @@ public class ExtendDataOperationTests extends RefineTest {
     // dependencies
     Project project;
     Properties options;
-    JSONObject engine_config;
+    EngineConfig engine_config;
     Engine engine;
 
     @BeforeMethod
@@ -91,8 +92,8 @@ public class ExtendDataOperationTests extends RefineTest {
         
         options = mock(Properties.class);
         engine = new Engine(project);
-        engine_config = new JSONObject(ENGINE_JSON_URLS);
+        engine_config = EngineConfig.reconstruct(new JSONObject(ENGINE_JSON_URLS));
-        engine.initializeFromJSON(engine_config);
+        engine.initializeFromConfig(engine_config);
         engine.setMode(Engine.Mode.RowBased);
 
                Row row = new Row(2);

main/tests/server/src/com/google/refine/tests/operations/recon/ReconCopyAcrossColumnsOperationTests.java

@@ -21,7 +21,7 @@ public class ReconCopyAcrossColumnsOperationTests extends RefineTest {
     public void serializeReconCopyAcrossColumnsOperation() throws Exception {
         String json = "{\"op\":\"core/recon-copy-across-columns\","
                 + "\"description\":\"Copy recon judgments from column source column to firstsecond\","
-                + "\"engineConfig\":{\"mode\":\"row-based\"},"
+                + "\"engineConfig\":{\"mode\":\"row-based\",\"facets\":[]},"
                 + "\"fromColumnName\":\"source column\","
                 + "\"toColumnNames\":[\"first\",\"second\"],"
                 + "\"judgments\":[\"matched\",\"new\"],"

main/tests/server/src/com/google/refine/tests/operations/recon/ReconJudgeSimilarCellsTests.java

@@ -11,6 +11,7 @@ import org.slf4j.LoggerFactory;
 import org.testng.annotations.BeforeTest;
 import org.testng.annotations.Test;
 
+import com.google.refine.browsing.EngineConfig;
 import com.google.refine.model.AbstractOperation;
 import com.google.refine.model.Cell;
 import com.google.refine.model.Column;
@@ -26,7 +27,7 @@ import com.google.refine.tests.util.TestUtils;
 
 public class ReconJudgeSimilarCellsTests extends RefineTest {
     
-    static final JSONObject ENGINE_CONFIG = new JSONObject("{\"mode\":\"row-based\"}}");
+    static final EngineConfig ENGINE_CONFIG = EngineConfig.reconstruct(new JSONObject("{\"mode\":\"row-based\"}}"));
     
     @Override
     @BeforeTest
@@ -45,7 +46,7 @@ public class ReconJudgeSimilarCellsTests extends RefineTest {
                 null, true);
         TestUtils.isSerializedTo(op, "{\"op\":\"core/recon-judge-similar-cells\","
                 + "\"description\":\"Mark to create one single new item for all cells containing \\\"foo\\\" in column A\","
-                + "\"engineConfig\":{\"mode\":\"row-based\"},"
+                + "\"engineConfig\":{\"mode\":\"row-based\",\"facets\":[]},"
                 + "\"columnName\":\"A\","
                 + "\"similarValue\":\"foo\","
                 + "\"judgment\":\"new\","

main/tests/server/src/com/google/refine/tests/operations/recon/ReconMarkNewTopicsOperationTests.java

@@ -21,7 +21,7 @@ public class ReconMarkNewTopicsOperationTests extends RefineTest {
     public void serializeReconMarkNewTopicsOperation() throws Exception {
         String json = "{"
                 + "\"op\":\"core/recon-mark-new-topics\","
-                + "\"engineConfig\":{\"mode\":\"row-based\"},"
+                + "\"engineConfig\":{\"mode\":\"row-based\",\"facets\":[]},"
                 + "\"columnName\":\"my column\","
                 + "\"shareNewTopics\":true,"
                 + "\"description\":\"Mark to create new items for cells in column my column, one item for each group of similar cells\""