Added start() and end() methods to RowVisitor and RecordVisitor so visitors can do things before and after all visitations.

Added sorting package. It's not hooked up, yet.

git-svn-id: http://google-refine.googlecode.com/svn/trunk@834 7d457c2a-affb-35e4-300a-418c747d4874

src/main/java/com/metaweb/gridworks/browsing/Engine.java

@@ -51,11 +51,17 @@ public class Engine implements Jsonizable {
         return new FilteredRows() {
 			@Override
 			public void accept(Project project, RowVisitor visitor) {
-		        int c = project.rows.size();
-		        for (int rowIndex = 0; rowIndex < c; rowIndex++) {
-		            Row row = project.rows.get(rowIndex);
-		            visitor.visit(project, rowIndex, row);
-		        }
+		    	try {
+		    		visitor.start(project);
+		    		
+			        int c = project.rows.size();
+			        for (int rowIndex = 0; rowIndex < c; rowIndex++) {
+			            Row row = project.rows.get(rowIndex);
+			            visitor.visit(project, rowIndex, row);
+			        }
+		    	} finally {
+		    		visitor.end(project);
+		    	}
 			}
         };
     }
@@ -86,10 +92,16 @@ public class Engine implements Jsonizable {
         return new FilteredRecords() {
 			@Override
 			public void accept(Project project, RecordVisitor visitor) {
-		        int c = project.recordModel.getRecordCount();
-		        for (int r = 0; r < c; r++) {
-		            visitor.visit(project, project.recordModel.getRecord(r));
-		        }
+		    	try {
+		    		visitor.start(project);
+		    		
+			        int c = project.recordModel.getRecordCount();
+			        for (int r = 0; r < c; r++) {
+			            visitor.visit(project, project.recordModel.getRecord(r));
+			        }
+		    	} finally {
+		    		visitor.end(project);
+		    	}
 			}
         };
     }

src/main/java/com/metaweb/gridworks/browsing/RecordVisitor.java

@@ -8,8 +8,12 @@ import com.metaweb.gridworks.model.Record;
  * particular criteria, such as facets' constraints.
  */
 public interface RecordVisitor {
+	public void start(Project project); // called before any visit() call
+	
     public boolean visit(
         Project project, 
         Record record
     );
+    
+	public void end(Project project); // called after all visit() calls
 }

src/main/java/com/metaweb/gridworks/browsing/RowVisitor.java

@@ -8,9 +8,13 @@ import com.metaweb.gridworks.model.Row;
  * particular criteria, such as facets' constraints.
  */
 public interface RowVisitor {
+	public void start(Project project); // called before any visit() call
+	
     public boolean visit(
         Project project, 
         int     rowIndex,   // zero-based row index 
         Row     row
     );
+    
+	public void end(Project project); // called after all visit() calls
 }

src/main/java/com/metaweb/gridworks/browsing/facets/ScatterplotDrawingRowVisitor.java

@@ -87,6 +87,16 @@ public class ScatterplotDrawingRowVisitor implements RowVisitor, RecordVisitor {
         g2.setPaint(color);
     }
     
+    @Override
+    public void start(Project project) {
+    	// nothing to do
+    }
+    
+    @Override
+    public void end(Project project) {
+    	// nothing to do
+    }
+    
     @Override
     public boolean visit(Project project, int rowIndex, Row row) {
         Cell cellx = row.getCell(col_x);

src/main/java/com/metaweb/gridworks/browsing/util/ConjunctiveFilteredRecords.java

@@ -21,15 +21,21 @@ public class ConjunctiveFilteredRecords implements FilteredRecords {
     
     @Override
     public void accept(Project project, RecordVisitor visitor) {
-    	int c = project.recordModel.getRecordCount();
-        for (int r = 0; r < c; r++) {
-        	Record record = project.recordModel.getRecord(r);
-            if (matchRecord(project, record)) {
-            	if (visitor.visit(project, record)) {
-            		return;
-            	}
-            }
-        }
+    	try {
+    		visitor.start(project);
+    		
+	    	int c = project.recordModel.getRecordCount();
+	        for (int r = 0; r < c; r++) {
+	        	Record record = project.recordModel.getRecord(r);
+	            if (matchRecord(project, record)) {
+	            	if (visitor.visit(project, record)) {
+	            		return;
+	            	}
+	            }
+	        }
+    	} finally {
+    		visitor.end(project);
+    	}
     }
     
     protected boolean matchRecord(Project project, Record record) {

src/main/java/com/metaweb/gridworks/browsing/util/ConjunctiveFilteredRows.java

@@ -21,13 +21,19 @@ public class ConjunctiveFilteredRows implements FilteredRows {
     }
     
     public void accept(Project project, RowVisitor visitor) {
-        int c = project.rows.size();
-        for (int rowIndex = 0; rowIndex < c; rowIndex++) {
-            Row row = project.rows.get(rowIndex);
-            if (matchRow(project, rowIndex, row)) {
-                visitRow(project, visitor, rowIndex, row);
-            }
-        }
+    	try {
+    		visitor.start(project);
+    		
+	        int c = project.rows.size();
+	        for (int rowIndex = 0; rowIndex < c; rowIndex++) {
+	            Row row = project.rows.get(rowIndex);
+	            if (matchRow(project, rowIndex, row)) {
+	                visitRow(project, visitor, rowIndex, row);
+	            }
+	        }
+    	} finally {
+    		visitor.end(project);
+    	}
     }
     
     protected void visitRow(Project project, RowVisitor visitor, int rowIndex, Row row) {

src/main/java/com/metaweb/gridworks/browsing/util/ExpressionNominalValueGrouper.java

@@ -56,6 +56,16 @@ public class ExpressionNominalValueGrouper implements RowVisitor, RecordVisitor
         _cellIndex = cellIndex;
     }
     
+    @Override
+    public void start(Project project) {
+    	// nothing to do
+    }
+    
+    @Override
+    public void end(Project project) {
+    	// nothing to do
+    }
+    
     public boolean visit(Project project, int rowIndex, Row row) {
     	hasError = false;
     	hasBlank = false;

src/main/java/com/metaweb/gridworks/browsing/util/ExpressionNumericValueBinner.java

@@ -50,6 +50,16 @@ public class ExpressionNumericValueBinner implements RowVisitor, RecordVisitor {
         bins = new int[_index.getBins().length];
     }
     
+    @Override
+    public void start(Project project) {
+    	// nothing to do
+    }
+    
+    @Override
+    public void end(Project project) {
+    	// nothing to do
+    }
+    
     @Override
     public boolean visit(Project project, int rowIndex, Row row) {
         resetFlags();

src/main/java/com/metaweb/gridworks/browsing/util/RowVisitorAsRecordVisitor.java

@@ -12,6 +12,16 @@ public class RowVisitorAsRecordVisitor implements RecordVisitor {
 		_rowVisitor = rowVisitor;
 	}
 
+    @Override
+    public void start(Project project) {
+    	_rowVisitor.start(project);
+    }
+    
+    @Override
+    public void end(Project project) {
+    	_rowVisitor.end(project);
+    }
+    
 	@Override
 	public boolean visit(Project project, Record record) {
 		for (int r = record.fromRowIndex; r < record.toRowIndex; r++) {

src/main/java/com/metaweb/gridworks/clustering/binning/BinningClusterer.java

@@ -66,6 +66,16 @@ public class BinningClusterer extends Clusterer {
             }
         }
         
+        @Override
+        public void start(Project project) {
+        	// nothing to do
+        }
+        
+        @Override
+        public void end(Project project) {
+        	// nothing to do
+        }
+        
         public boolean visit(Project project, int rowIndex, Row row) {
             Cell cell = row.getCell(_colindex);
             if (cell != null && cell.value != null) {

src/main/java/com/metaweb/gridworks/clustering/knn/kNNClusterer.java

@@ -80,6 +80,16 @@ public class kNNClusterer extends Clusterer {
             }
         }
         
+        @Override
+        public void start(Project project) {
+        	// nothing to do
+        }
+        
+        @Override
+        public void end(Project project) {
+        	// nothing to do
+        }
+        
         public boolean visit(Project project, int rowIndex, Row row) {
             Cell cell = row.getCell(_colindex);
             if (cell != null && cell.value != null) {
@@ -121,6 +131,16 @@ public class kNNClusterer extends Clusterer {
             _clusterer = new NGramClusterer(_distance, _blockingNgramSize);
         }
         
+        @Override
+        public void start(Project project) {
+        	// nothing to do
+        }
+        
+        @Override
+        public void end(Project project) {
+        	// nothing to do
+        }
+        
         public boolean visit(Project project, int rowIndex, Row row) {
             Cell cell = row.getCell(_colindex);
             if (cell != null && cell.value != null) {

src/main/java/com/metaweb/gridworks/commands/row/GetRowsCommand.java

@@ -94,6 +94,16 @@ public class GetRowsCommand extends Command {
             this.options = options;
         }
         
+        @Override
+        public void start(Project project) {
+        	// nothing to do
+        }
+        
+        @Override
+        public void end(Project project) {
+        	// nothing to do
+        }
+        
         public boolean visit(Project project, int rowIndex, Row row) {
             if (total >= start && total < start + limit) {
                 internalVisit(project, rowIndex, row);

src/main/java/com/metaweb/gridworks/exporters/HtmlTableExporter.java

@@ -56,6 +56,16 @@ public class HtmlTableExporter implements Exporter {
                     return this;
                 }
                 
+                @Override
+                public void start(Project project) {
+                	// nothing to do
+                }
+                
+                @Override
+                public void end(Project project) {
+                	// nothing to do
+                }
+                
                 public boolean visit(Project project, int rowIndex, Row row) {
                     try {
                         writer.write("<tr>");

src/main/java/com/metaweb/gridworks/exporters/TsvExporter.java

@@ -48,6 +48,16 @@ public class TsvExporter implements Exporter {
                     return this;
                 }
                 
+                @Override
+                public void start(Project project) {
+                	// nothing to do
+                }
+                
+                @Override
+                public void end(Project project) {
+                	// nothing to do
+                }
+                
                 public boolean visit(Project project, int rowIndex, Row row) {
                     boolean first = true;
                     try {

src/main/java/com/metaweb/gridworks/exporters/XlsExporter.java

@@ -64,6 +64,16 @@ public class XlsExporter implements Exporter {
                     return this;
                 }
                 
+                @Override
+                public void start(Project project) {
+                	// nothing to do
+                }
+                
+                @Override
+                public void end(Project project) {
+                	// nothing to do
+                }
+                
                 public boolean visit(Project project, int rowIndex, Row row) {
                     org.apache.poi.ss.usermodel.Row r = sheet.createRow(rowCount++);
                     

src/main/java/com/metaweb/gridworks/operations/ColumnAdditionOperation.java

@@ -135,6 +135,16 @@ public class ColumnAdditionOperation extends EngineDependentOperation {
                 return this;
             }
             
+            @Override
+            public void start(Project project) {
+            	// nothing to do
+            }
+            
+            @Override
+            public void end(Project project) {
+            	// nothing to do
+            }
+            
             public boolean visit(Project project, int rowIndex, Row row) {
                 Cell cell = row.getCell(cellIndex);
                 Cell newCell = null;

src/main/java/com/metaweb/gridworks/operations/ColumnSplitOperation.java

@@ -234,6 +234,16 @@ public class ColumnSplitOperation extends EngineDependentOperation {
             this.tuples = tuples;
         }
         
+        @Override
+        public void start(Project project) {
+        	// nothing to do
+        }
+        
+        @Override
+        public void end(Project project) {
+        	// nothing to do
+        }
+        
         public boolean visit(Project project, int rowIndex, Row row) {
             Object value = row.getCellValue(cellIndex);
             if (ExpressionUtils.isNonBlankData(value)) {

src/main/java/com/metaweb/gridworks/operations/ExtendDataOperation.java

@@ -148,6 +148,17 @@ public class ExtendDataOperation extends EngineDependentOperation {
                     _rowIndices = rowIndices;
                     return this;
                 }
+                
+                @Override
+                public void start(Project project) {
+                	// nothing to do
+                }
+                
+                @Override
+                public void end(Project project) {
+                	// nothing to do
+                }
+                
                 public boolean visit(Project project, int rowIndex, Row row) {
                     Cell cell = row.getCell(_cellIndex);
                     if (cell != null && cell.recon != null && cell.recon.match != null) {

src/main/java/com/metaweb/gridworks/operations/MassEditOperation.java

@@ -196,6 +196,16 @@ public class MassEditOperation extends EngineDependentMassCellOperation {
                 return this;
             }
             
+            @Override
+            public void start(Project project) {
+            	// nothing to do
+            }
+            
+            @Override
+            public void end(Project project) {
+            	// nothing to do
+            }
+            
             public boolean visit(Project project, int rowIndex, Row row) {
                 Cell cell = row.getCell(cellIndex);
                 Cell newCell = null;

src/main/java/com/metaweb/gridworks/operations/ReconDiscardJudgmentsOperation.java

@@ -74,6 +74,16 @@ public class ReconDiscardJudgmentsOperation extends EngineDependentMassCellOpera
                 return this;
             }
             
+            @Override
+            public void start(Project project) {
+            	// nothing to do
+            }
+            
+            @Override
+            public void end(Project project) {
+            	// nothing to do
+            }
+            
             public boolean visit(Project project, int rowIndex, Row row) {
                 Cell cell = row.getCell(cellIndex);
                 if (cell != null && cell.recon != null) {

src/main/java/com/metaweb/gridworks/operations/ReconJudgeSimilarCellsOperation.java

@@ -162,6 +162,16 @@ public class ReconJudgeSimilarCellsOperation extends EngineDependentMassCellOper
                 return this;
             }
             
+            @Override
+            public void start(Project project) {
+            	// nothing to do
+            }
+            
+            @Override
+            public void end(Project project) {
+            	// nothing to do
+            }
+            
             public boolean visit(Project project, int rowIndex, Row row) {
                 Cell cell = row.getCell(_cellIndex);
                 if (cell != null && ExpressionUtils.isNonBlankData(cell.value)) {

src/main/java/com/metaweb/gridworks/operations/ReconMarkNewTopicsOperation.java

@@ -84,6 +84,16 @@ public class ReconMarkNewTopicsOperation extends EngineDependentMassCellOperatio
                 return this;
             }
             
+            @Override
+            public void start(Project project) {
+            	// nothing to do
+            }
+            
+            @Override
+            public void end(Project project) {
+            	// nothing to do
+            }
+            
             public boolean visit(Project project, int rowIndex, Row row) {
                 Cell cell = row.getCell(cellIndex);
                 if (cell != null) {

src/main/java/com/metaweb/gridworks/operations/ReconMatchBestCandidatesOperation.java

@@ -75,6 +75,16 @@ public class ReconMatchBestCandidatesOperation extends EngineDependentMassCellOp
                 return this;
             }
             
+            @Override
+            public void start(Project project) {
+            	// nothing to do
+            }
+            
+            @Override
+            public void end(Project project) {
+            	// nothing to do
+            }
+            
             public boolean visit(Project project, int rowIndex, Row row) {
                 if (cellIndex < row.cells.size()) {
                     Cell cell = row.cells.get(cellIndex);

src/main/java/com/metaweb/gridworks/operations/ReconMatchSpecificTopicOperation.java

@@ -108,6 +108,16 @@ public class ReconMatchSpecificTopicOperation extends EngineDependentMassCellOpe
                 return this;
             }
             
+            @Override
+            public void start(Project project) {
+            	// nothing to do
+            }
+            
+            @Override
+            public void end(Project project) {
+            	// nothing to do
+            }
+            
             public boolean visit(Project project, int rowIndex, Row row) {
                 Cell cell = row.getCell(cellIndex);
                 if (cell != null) {

src/main/java/com/metaweb/gridworks/operations/ReconOperation.java

@@ -176,6 +176,16 @@ public class ReconOperation extends EngineDependentOperation {
             
             FilteredRows filteredRows = engine.getAllFilteredRows();
             filteredRows.accept(_project, new RowVisitor() {
+                @Override
+                public void start(Project project) {
+                	// nothing to do
+                }
+                
+                @Override
+                public void end(Project project) {
+                	// nothing to do
+                }
+                
                 public boolean visit(Project project, int rowIndex, Row row) {
                     if (_cellIndex < row.cells.size()) {
                         Cell cell = row.cells.get(_cellIndex);

src/main/java/com/metaweb/gridworks/operations/RowFlagOperation.java

@@ -78,6 +78,16 @@ public class RowFlagOperation extends EngineDependentOperation {
                 return this;
             }
             
+            @Override
+            public void start(Project project) {
+            	// nothing to do
+            }
+            
+            @Override
+            public void end(Project project) {
+            	// nothing to do
+            }
+            
             public boolean visit(Project project, int rowIndex, Row row) {
                 if (row.flagged != _flagged) {
                     RowFlagChange change = new RowFlagChange(rowIndex, _flagged);

src/main/java/com/metaweb/gridworks/operations/RowRemovalOperation.java

@@ -70,6 +70,16 @@ public class RowRemovalOperation extends EngineDependentOperation {
                 return this;
             }
             
+            @Override
+            public void start(Project project) {
+            	// nothing to do
+            }
+            
+            @Override
+            public void end(Project project) {
+            	// nothing to do
+            }
+            
             public boolean visit(Project project, int rowIndex, Row row) {
                 rowIndices.add(rowIndex);
                 

src/main/java/com/metaweb/gridworks/operations/RowStarOperation.java

@@ -78,6 +78,16 @@ public class RowStarOperation extends EngineDependentOperation {
                 return this;
             }
             
+            @Override
+            public void start(Project project) {
+            	// nothing to do
+            }
+            
+            @Override
+            public void end(Project project) {
+            	// nothing to do
+            }
+            
             public boolean visit(Project project, int rowIndex, Row row) {
                 if (row.starred != _starred) {
                     RowStarChange change = new RowStarChange(rowIndex, _starred);

src/main/java/com/metaweb/gridworks/operations/TextTransformOperation.java

@@ -119,6 +119,16 @@ public class TextTransformOperation extends EngineDependentMassCellOperation {
                 return this;
             }
             
+            @Override
+            public void start(Project project) {
+            	// nothing to do
+            }
+            
+            @Override
+            public void end(Project project) {
+            	// nothing to do
+            }
+            
             public boolean visit(Project project, int rowIndex, Row row) {
                 Cell cell = row.getCell(cellIndex);
                 Cell newCell = null;

src/main/java/com/metaweb/gridworks/sorting/BaseSorter.java

@@ -0,0 +1,136 @@
+package com.metaweb.gridworks.sorting;
+
+import java.util.List;
+
+import org.json.JSONArray;
+import org.json.JSONException;
+import org.json.JSONObject;
+
+import com.metaweb.gridworks.expr.EvalError;
+import com.metaweb.gridworks.model.Project;
+import com.metaweb.gridworks.sorting.Criterion.KeyMaker;
+
+abstract public class BaseSorter {
+	protected Criterion[] 			_criteria;
+	protected KeyMaker[] 			_keyMakers;
+	protected ComparatorWrapper[]	_comparatorWrappers;
+	protected List<Object[]>		_keys;
+	
+	public class ComparatorWrapper {
+		final public int 		criterionIndex;
+		final protected int 	multiplier;
+		
+		public ComparatorWrapper(int criterionIndex) {
+			this.criterionIndex = criterionIndex;
+			this.multiplier = _criteria[criterionIndex].reverse ? -1 : 1;
+		}
+		
+		public Object getKey(Project project, Object o, int index) {
+			Object[] keys = _keys.get(index);
+			if (keys == null) {
+				keys = makeKeys(project, o, index);
+				_keys.set(index, keys);
+			}
+			return keys[criterionIndex];
+		}
+		
+		public int compare(Project project, Object o1, int i1, Object o2, int i2) {
+			Criterion c = _criteria[criterionIndex];
+			Object key1 = getKey(project, o1, i1);
+			Object key2 = getKey(project, o2, i2);
+			
+			if (key1 == null) {
+				if (key2 == null) {
+					return 0;
+				} else if (key2 instanceof EvalError) {
+					return c.blankPosition - c.errorPosition;
+				} else {
+					return c.blankPosition;
+				}
+			} else if (key1 instanceof EvalError) {
+				if (key2 == null) {
+					return c.errorPosition - c.blankPosition;
+				} else if (key2 instanceof EvalError) {
+					return 0;
+				} else {
+					return c.errorPosition;
+				}
+			} else {
+				if (key2 == null) {
+					return -c.blankPosition;
+				} else if (key2 instanceof EvalError) {
+					return -c.errorPosition;
+				} else {
+					return _keyMakers[criterionIndex].compareKeys(key1, key2) * multiplier;
+				}
+			}
+		}
+	}
+	
+	public void initializeFromJSON(Project project, JSONObject obj) throws JSONException {
+		if (obj.has("criteria") && !obj.isNull("criteria")) {
+			JSONArray a = obj.getJSONArray("criteria");
+			int count = a.length();
+			
+			_criteria = new Criterion[count];
+			_keyMakers = new KeyMaker[count];
+			_comparatorWrappers = new ComparatorWrapper[count];
+			
+			for (int i = 0; i < count; i++) {
+				JSONObject obj2 = a.getJSONObject(i);
+				
+				_criteria[i] = createCriterionFromJSON(project, obj2);
+				_keyMakers[i] = _criteria[i].createKeyMaker();
+				_comparatorWrappers[i] = new ComparatorWrapper(i);
+			}
+		} else {
+			_criteria = new Criterion[0];
+			_keyMakers = new KeyMaker[0];
+			_comparatorWrappers = new ComparatorWrapper[0];
+		}
+	}
+	
+	public boolean hasCriteria() {
+		return _criteria != null && _criteria.length > 0;
+	}
+	
+	protected Criterion createCriterionFromJSON(Project project, JSONObject obj) throws JSONException {
+		String valueType = "string";
+		if (obj.has("valueType") && !obj.isNull("valueType")) {
+			valueType = obj.getString("valueType");
+		}
+		
+		Criterion c = null;
+		if ("boolean".equals(valueType)) {
+			c = new BooleanCriterion();
+		} else if ("date".equals(valueType)) {
+			c = new DateCriterion();
+		} else if ("number".equals(valueType)) {
+			c = new NumberCriterion();
+		} else {
+			c = new StringCriterion();
+		}
+		
+		c.initializeFromJSON(project, obj);
+		return c;
+	}
+	
+	abstract protected Object makeKey(
+			Project project, KeyMaker keyMaker, Criterion c, Object o, int index);
+	
+	protected Object[] makeKeys(Project project, Object o, int index) {
+		Object[] keys = new Object[_keyMakers.length];
+		for (int i = 0; i < keys.length; i++) {
+			keys[i] = makeKey(project, _keyMakers[i], _criteria[i], o, index);
+		}
+		return keys;
+	}
+	
+	protected int compare(Project project, Object o1, int i1, Object o2, int i2) {
+		int c = 0;
+		for (int i = 0; c == 0 && i < _comparatorWrappers.length; i++) {
+			c = _comparatorWrappers[i].compare(project, o1, i1, o2, i2);
+		}
+		return c;
+	}
+}

src/main/java/com/metaweb/gridworks/sorting/BooleanCriterion.java

@@ -0,0 +1,32 @@
+package com.metaweb.gridworks.sorting;
+
+import com.metaweb.gridworks.expr.EvalError;
+import com.metaweb.gridworks.expr.ExpressionUtils;
+
+public class BooleanCriterion extends Criterion {
+	final static protected EvalError s_error = new EvalError("Not a boolean");
+	
+	@Override
+	public KeyMaker createKeyMaker() {
+		return new KeyMaker() {
+			@Override
+			protected Object makeKey(Object value) {
+				if (ExpressionUtils.isNonBlankData(value)) {
+					if (value instanceof Boolean) {
+						return value;
+					} else if (value instanceof String) {
+						return Boolean.parseBoolean((String) value);
+					} else {
+						return s_error;
+					}
+				}
+				return value;
+			}
+			
+			@Override
+			public int compareKeys(Object key1, Object key2) {
+				return ((Boolean) key1).compareTo((Boolean) key2);
+			}
+		};
+	}
+}

src/main/java/com/metaweb/gridworks/sorting/Criterion.java

@@ -0,0 +1,94 @@
+package com.metaweb.gridworks.sorting;
+
+import org.json.JSONException;
+import org.json.JSONObject;
+
+import com.metaweb.gridworks.expr.ExpressionUtils;
+import com.metaweb.gridworks.model.Column;
+import com.metaweb.gridworks.model.Project;
+import com.metaweb.gridworks.model.Record;
+import com.metaweb.gridworks.model.Row;
+
+abstract public class Criterion {
+	public String columnName;
+	protected int cellIndex;
+	
+	// These take on positive and negative values to indicate where blanks and errors
+	// go relative to non-blank values. They are also relative to each another.
+	// Blanks and errors are not affected by the reverse flag.
+	public int blankPosition = 1;
+	public int errorPosition = 2;
+	
+	public boolean reverse;
+	
+	public void initializeFromJSON(Project project, JSONObject obj) throws JSONException {
+		if (obj.has("column") && !obj.isNull("column")) {
+			columnName = obj.getString("column");
+			
+			Column column = project.columnModel.getColumnByName(columnName);
+			cellIndex = column != null ? column.getCellIndex() : -1;
+		}
+		
+		if (obj.has("blankPosition") && !obj.isNull("blankPosition")) {
+			blankPosition = obj.getInt("blankPosition");
+		}
+		if (obj.has("errorPosition") && !obj.isNull("errorPosition")) {
+			blankPosition = obj.getInt("errorPosition");
+		}
+		
+		if (obj.has("reverse") && !obj.isNull("reverse")) {
+			reverse = obj.getBoolean("reverse");
+		}
+	}
+	
+	abstract public class KeyMaker {
+		public Object makeKey(Project project, Record record) {
+			Object error = null;
+			Object finalKey = null;
+			
+			for (int r = record.fromRowIndex; r < record.toRowIndex; r++) {
+				Object key = makeKey(project, project.rows.get(r), r);
+				if (ExpressionUtils.isError(key)) {
+					error = key;
+				} else if (ExpressionUtils.isNonBlankData(key)) {
+					if (finalKey == null) {
+						finalKey = key;
+					} else {
+						int c = compareKeys(finalKey, key);
+						if (reverse) {
+							if (c < 0) { // key > finalKey
+								finalKey = key;
+							}
+						} else {
+							if (c > 0) { // key < finalKey
+								finalKey = key;
+							}
+						}
+					}
+				}
+			}
+			
+			if (finalKey != null) {
+				return finalKey;
+			} else if (error != null) {
+				return error;
+			} else {
+				return null;
+			}
+		}
+		
+		public Object makeKey(Project project, Row row, int rowIndex) {
+			if (cellIndex < 0) {
+				return null;
+			} else {
+				Object value = row.getCellValue(cellIndex);
+				return makeKey(value);
+			}
+		}
+		
+		abstract public int compareKeys(Object key1, Object key2);
+		
+		abstract protected Object makeKey(Object value);
+	}
+	abstract public KeyMaker createKeyMaker();
+}

src/main/java/com/metaweb/gridworks/sorting/DateCriterion.java

@@ -0,0 +1,35 @@
+package com.metaweb.gridworks.sorting;
+
+import java.util.Calendar;
+import java.util.Date;
+
+import com.metaweb.gridworks.expr.EvalError;
+import com.metaweb.gridworks.expr.ExpressionUtils;
+
+public class DateCriterion extends Criterion {
+	final static protected EvalError s_error = new EvalError("Not a date");
+	
+	@Override
+	public KeyMaker createKeyMaker() {
+		return new KeyMaker() {
+			@Override
+			protected Object makeKey(Object value) {
+				if (ExpressionUtils.isNonBlankData(value)) {
+					if (value instanceof Date) {
+						return value;
+					} else if (value instanceof Calendar) {
+						return ((Calendar) value).getTime();
+					} else {
+						return s_error;
+					}
+				}
+				return value;
+			}
+			
+			@Override
+			public int compareKeys(Object key1, Object key2) {
+				return ((Date) key1).compareTo((Date) key2);
+			}
+		};
+	}
+}

src/main/java/com/metaweb/gridworks/sorting/NumberCriterion.java

@@ -0,0 +1,50 @@
+package com.metaweb.gridworks.sorting;
+
+import java.util.Calendar;
+import java.util.Date;
+
+import com.metaweb.gridworks.expr.EvalError;
+import com.metaweb.gridworks.expr.ExpressionUtils;
+
+public class NumberCriterion extends Criterion {
+	
+	final static protected EvalError s_error = new EvalError("Not a number");
+	
+	@Override
+	public KeyMaker createKeyMaker() {
+		return new KeyMaker() {
+			@Override
+			protected Object makeKey(Object value) {
+				if (ExpressionUtils.isNonBlankData(value)) {
+					if (value instanceof Number) {
+						return value;
+					} else if (value instanceof Boolean) {
+						return ((Boolean) value).booleanValue() ? 1 : 0;
+					} else if (value instanceof Date) {
+						return ((Date) value).getTime();
+					} else if (value instanceof Calendar) {
+						return ((Calendar) value).getTime().getTime();
+					} else if (value instanceof String) {
+						try {
+							double d = Double.parseDouble((String) value);
+							if (!Double.isNaN(d)) {
+								return d;
+							}
+						} catch (NumberFormatException e) {
+							// fall through
+						}
+					}
+					return s_error;
+				}
+				return value;
+			}
+			
+			@Override
+			public int compareKeys(Object key1, Object key2) {
+				double d1 = ((Number) key1).doubleValue();
+				double d2 = ((Number) key2).doubleValue();
+				return d1 < d2 ? -1 : (d1 > d2 ? 1 : 0);
+			}
+		};
+	}
+}

src/main/java/com/metaweb/gridworks/sorting/SortingRecordVisitor.java

@@ -0,0 +1,60 @@
+package com.metaweb.gridworks.sorting;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+
+import com.metaweb.gridworks.browsing.RecordVisitor;
+import com.metaweb.gridworks.browsing.RowVisitor;
+import com.metaweb.gridworks.model.Project;
+import com.metaweb.gridworks.model.Record;
+import com.metaweb.gridworks.sorting.Criterion.KeyMaker;
+
+public class SortingRecordVisitor extends BaseSorter implements RecordVisitor {
+	final protected RowVisitor 	_visitor;
+	protected List<Record> 		_records;
+	
+	public SortingRecordVisitor(RowVisitor visitor) {
+		_visitor = visitor;
+	}
+
+	@Override
+	public void start(Project project) {
+		_records = new ArrayList<Record>(project.recordModel.getRecordCount());
+	}
+
+	@Override
+	public void end(Project project) {
+		_visitor.start(project);
+		
+		Collections.sort(_records, new Comparator<Record>() {
+			Project project;
+			
+			Comparator<Record> init(Project project) {
+				this.project = project;
+				return this;
+			}
+			
+			@Override
+			public int compare(Record o1, Record o2) {
+				return SortingRecordVisitor.this.compare(project, o1, o1.recordIndex, o2, o2.recordIndex);
+			}
+		}.init(project));
+		
+		_visitor.end(project);
+	}
+
+	@Override
+	public boolean visit(Project project, Record record) {
+		_records.add(record);
+		return false;
+	}
+
+	@Override
+	protected Object makeKey(
+			Project project, KeyMaker keyMaker, Criterion c, Object o, int index) {
+		
+		return keyMaker.makeKey(project, (Record) o);
+	}
+}

src/main/java/com/metaweb/gridworks/sorting/SortingRowVisitor.java

@@ -0,0 +1,69 @@
+package com.metaweb.gridworks.sorting;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+
+import com.metaweb.gridworks.browsing.RowVisitor;
+import com.metaweb.gridworks.model.Project;
+import com.metaweb.gridworks.model.Row;
+import com.metaweb.gridworks.sorting.Criterion.KeyMaker;
+
+public class SortingRowVisitor extends BaseSorter implements RowVisitor {
+	final protected RowVisitor 	_visitor;
+	protected List<IndexedRow> 	_indexedRows;
+	
+	static protected class IndexedRow {
+		final int index;
+		final Row row;
+		
+		IndexedRow(int index, Row row) {
+			this.index = index;
+			this.row = row;
+		}
+	}
+	
+	public SortingRowVisitor(RowVisitor visitor) {
+		_visitor = visitor;
+	}
+
+	@Override
+	public void start(Project project) {
+		_indexedRows = new ArrayList<IndexedRow>(project.rows.size());
+	}
+
+	@Override
+	public void end(Project project) {
+		_visitor.start(project);
+		
+		Collections.sort(_indexedRows, new Comparator<IndexedRow>() {
+			Project project;
+			
+			Comparator<IndexedRow> init(Project project) {
+				this.project = project;
+				return this;
+			}
+			
+			@Override
+			public int compare(IndexedRow o1, IndexedRow o2) {
+				return SortingRowVisitor.this.compare(project, o1.row, o1.index, o2.row, o2.index);
+			}
+		}.init(project));
+		
+		_visitor.end(project);
+	}
+
+	@Override
+	public boolean visit(Project project, int rowIndex, Row row) {
+		_indexedRows.add(new IndexedRow(rowIndex, row));
+		return false;
+	}
+
+	@Override
+	protected Object makeKey(
+			Project project, KeyMaker keyMaker, Criterion c, Object o, int index) {
+		
+		return keyMaker.makeKey(project, (Row) o, index);
+	}
+}

src/main/java/com/metaweb/gridworks/sorting/StringCriterion.java

@@ -0,0 +1,40 @@
+package com.metaweb.gridworks.sorting;
+
+import org.json.JSONException;
+import org.json.JSONObject;
+
+import com.metaweb.gridworks.expr.ExpressionUtils;
+import com.metaweb.gridworks.model.Project;
+
+public class StringCriterion extends Criterion {
+	public boolean caseSensitive;
+	
+	@Override
+	public void initializeFromJSON(Project project, JSONObject obj) throws JSONException {
+		super.initializeFromJSON(project, obj);
+		
+		if (obj.has("caseSensitive") && !obj.isNull("caseSensitive")) {
+			caseSensitive = obj.getBoolean("caseSensitive");
+		}
+	}
+	
+	@Override
+	public KeyMaker createKeyMaker() {
+		return new KeyMaker() {
+			@Override
+			protected Object makeKey(Object value) {
+				return (ExpressionUtils.isNonBlankData(value) && !(value instanceof String)) ?
+						value.toString() : value;
+			}
+			
+			@Override
+			public int compareKeys(Object key1, Object key2) {
+				if (StringCriterion.this.caseSensitive) {
+					return ((String) key1).compareTo((String) key2);
+				} else {
+					return ((String) key1).compareToIgnoreCase((String) key2);
+				}
+			}
+		};
+	}
+}