Refactor ItemUpdate and introduce ItemUpdateBuilder

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

@@ -54,8 +54,9 @@ import org.openrefine.wikidata.exporters.QuickStatementsExporter;
 import org.openrefine.wikidata.qa.EditInspector;
 import org.openrefine.wikidata.qa.QAWarning;
 import org.openrefine.wikidata.qa.QAWarningStore;
-import org.openrefine.wikidata.schema.ItemUpdate;
 import org.openrefine.wikidata.schema.WikibaseSchema;
+import org.openrefine.wikidata.updates.ItemUpdate;
+
 import com.google.refine.model.Project;
 import com.google.refine.util.ParsingUtilities;
 

extensions/wikidata/src/org/openrefine/wikidata/exporters/QuickStatementsExporter.java

@@ -10,8 +10,8 @@ import com.google.refine.browsing.Engine;
 import com.google.refine.exporters.WriterExporter;
 import com.google.refine.model.Project;
 
-import org.openrefine.wikidata.schema.ItemUpdate;
 import org.openrefine.wikidata.schema.WikibaseSchema;
+import org.openrefine.wikidata.updates.ItemUpdate;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.wikidata.wdtk.datamodel.interfaces.Claim;

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

@@ -6,7 +6,6 @@ import java.io.Writer;
 import java.util.HashMap;
 import java.util.List;
 import java.util.ArrayList;
-import java.util.Collections;
 import java.util.Map;
 import java.util.Properties;
 import java.util.stream.Collectors;
@@ -17,7 +16,7 @@ import org.json.JSONWriter;
 
 import org.openrefine.wikidata.editing.ConnectionManager;
 import org.openrefine.wikidata.editing.NewItemLibrary;
-import org.openrefine.wikidata.schema.ItemUpdate;
+import org.openrefine.wikidata.updates.ItemUpdate;
 import org.openrefine.wikidata.schema.WikibaseSchema;
 import org.openrefine.wikidata.schema.entityvalues.ReconEntityIdValue;
 import org.slf4j.Logger;
@@ -30,7 +29,6 @@ import org.wikidata.wdtk.datamodel.interfaces.ItemDocument;
 import org.wikidata.wdtk.datamodel.interfaces.MonolingualTextValue;
 import org.wikidata.wdtk.util.WebResourceFetcherImpl;
 import org.wikidata.wdtk.wikibaseapi.ApiConnection;
-import org.wikidata.wdtk.wikibaseapi.TermStatementUpdate;
 import org.wikidata.wdtk.wikibaseapi.WikibaseDataEditor;
 import org.wikidata.wdtk.wikibaseapi.WikibaseDataFetcher;
 import org.wikidata.wdtk.wikibaseapi.apierrors.MediaWikiApiErrorException;

extensions/wikidata/src/org/openrefine/wikidata/qa/EditInspector.java

@@ -17,7 +17,7 @@ import org.openrefine.wikidata.qa.scrutinizers.SelfReferentialScrutinizer;
 import org.openrefine.wikidata.qa.scrutinizers.SingleValueScrutinizer;
 import org.openrefine.wikidata.qa.scrutinizers.UnsourcedScrutinizer;
 import org.openrefine.wikidata.qa.scrutinizers.WhitespaceScrutinizer;
-import org.openrefine.wikidata.schema.ItemUpdate;
+import org.openrefine.wikidata.updates.ItemUpdate;
 import org.wikidata.wdtk.datamodel.interfaces.EntityIdValue;
 
 /**

extensions/wikidata/src/org/openrefine/wikidata/qa/scrutinizers/EditScrutinizer.java

@@ -1,13 +1,12 @@
 package org.openrefine.wikidata.qa.scrutinizers;
 
 import java.util.List;
-import java.util.Map;
 
 import org.openrefine.wikidata.qa.ConstraintFetcher;
 import org.openrefine.wikidata.qa.QAWarning;
 import org.openrefine.wikidata.qa.QAWarning.Severity;
 import org.openrefine.wikidata.qa.QAWarningStore;
-import org.openrefine.wikidata.schema.ItemUpdate;
+import org.openrefine.wikidata.updates.ItemUpdate;
 
 /**
  * Interface for any class that 

extensions/wikidata/src/org/openrefine/wikidata/qa/scrutinizers/ItemEditScrutinizer.java

@@ -2,7 +2,7 @@ package org.openrefine.wikidata.qa.scrutinizers;
 
 import java.util.List;
 
-import org.openrefine.wikidata.schema.ItemUpdate;
+import org.openrefine.wikidata.updates.ItemUpdate;
 
 public abstract class ItemEditScrutinizer extends EditScrutinizer {
 

extensions/wikidata/src/org/openrefine/wikidata/qa/scrutinizers/NewItemScrutinizer.java

@@ -1,7 +1,7 @@
 package org.openrefine.wikidata.qa.scrutinizers;
 
 import org.openrefine.wikidata.qa.QAWarning;
-import org.openrefine.wikidata.schema.ItemUpdate;
+import org.openrefine.wikidata.updates.ItemUpdate;
 import org.wikidata.wdtk.datamodel.interfaces.StatementGroup;
 
 /**

extensions/wikidata/src/org/openrefine/wikidata/qa/scrutinizers/NoEditsMadeScrutinizer.java

@@ -2,7 +2,7 @@ package org.openrefine.wikidata.qa.scrutinizers;
 
 import java.util.List;
 
-import org.openrefine.wikidata.schema.ItemUpdate;
+import org.openrefine.wikidata.updates.ItemUpdate;
 
 
 public class NoEditsMadeScrutinizer extends EditScrutinizer {

extensions/wikidata/src/org/openrefine/wikidata/qa/scrutinizers/SingleValueScrutinizer.java

@@ -4,7 +4,7 @@ import java.util.HashSet;
 import java.util.Set;
 
 import org.openrefine.wikidata.qa.QAWarning;
-import org.openrefine.wikidata.schema.ItemUpdate;
+import org.openrefine.wikidata.updates.ItemUpdate;
 import org.wikidata.wdtk.datamodel.interfaces.PropertyIdValue;
 import org.wikidata.wdtk.datamodel.interfaces.Statement;
 

extensions/wikidata/src/org/openrefine/wikidata/qa/scrutinizers/StatementGroupScrutinizer.java

@@ -1,6 +1,6 @@
 package org.openrefine.wikidata.qa.scrutinizers;
 
-import org.openrefine.wikidata.schema.ItemUpdate;
+import org.openrefine.wikidata.updates.ItemUpdate;
 import org.wikidata.wdtk.datamodel.interfaces.StatementGroup;
 
 public abstract class StatementGroupScrutinizer extends ItemEditScrutinizer {

extensions/wikidata/src/org/openrefine/wikidata/qa/scrutinizers/StatementScrutinizer.java

@@ -1,6 +1,6 @@
 package org.openrefine.wikidata.qa.scrutinizers;
 
-import org.openrefine.wikidata.schema.ItemUpdate;
+import org.openrefine.wikidata.updates.ItemUpdate;
 import org.wikidata.wdtk.datamodel.interfaces.EntityIdValue;
 import org.wikidata.wdtk.datamodel.interfaces.Statement;
 

extensions/wikidata/src/org/openrefine/wikidata/qa/scrutinizers/ValueScrutinizer.java

@@ -1,6 +1,6 @@
 package org.openrefine.wikidata.qa.scrutinizers;
 
-import org.openrefine.wikidata.schema.ItemUpdate;
+import org.openrefine.wikidata.updates.ItemUpdate;
 import org.wikidata.wdtk.datamodel.interfaces.EntityIdValue;
 import org.wikidata.wdtk.datamodel.interfaces.MonolingualTextValue;
 import org.wikidata.wdtk.datamodel.interfaces.Snak;

extensions/wikidata/src/org/openrefine/wikidata/schema/WbItemDocumentExpr.java

@@ -3,6 +3,8 @@ package org.openrefine.wikidata.schema;
 import java.util.List;
 
 import org.openrefine.wikidata.schema.exceptions.SkipSchemaExpressionException;
+import org.openrefine.wikidata.updates.ItemUpdate;
+import org.openrefine.wikidata.updates.ItemUpdateBuilder;
 import org.openrefine.wikidata.utils.JacksonJsonizable;
 import org.wikidata.wdtk.datamodel.interfaces.ItemIdValue;
 import org.wikidata.wdtk.datamodel.interfaces.Statement;
@@ -40,7 +42,7 @@ public class WbItemDocumentExpr extends JacksonJsonizable implements WbExpressio
     @Override
     public ItemUpdate evaluate(ExpressionContext ctxt) throws SkipSchemaExpressionException {
         ItemIdValue subjectId = getSubject().evaluate(ctxt);
-        ItemUpdate update = new ItemUpdate(subjectId);
+        ItemUpdateBuilder update = new ItemUpdateBuilder(subjectId);
         for(WbStatementGroupExpr expr : getStatementGroups()) {
             try {
                 for(Statement s : expr.evaluate(ctxt, subjectId).getStatements()) {
@@ -53,7 +55,7 @@ public class WbItemDocumentExpr extends JacksonJsonizable implements WbExpressio
         for(WbNameDescExpr expr : getNameDescs()) {
             expr.contributeTo(update, ctxt);
         }
-        return update;
+        return update.build();
     }
 
     @JsonProperty("subject")

extensions/wikidata/src/org/openrefine/wikidata/schema/WbNameDescExpr.java

@@ -2,6 +2,7 @@ package org.openrefine.wikidata.schema;
 
 import org.jsoup.helper.Validate;
 import org.openrefine.wikidata.schema.exceptions.SkipSchemaExpressionException;
+import org.openrefine.wikidata.updates.ItemUpdateBuilder;
 import org.wikidata.wdtk.datamodel.interfaces.MonolingualTextValue;
 
 import com.fasterxml.jackson.annotation.JsonCreator;
@@ -11,7 +12,7 @@ import com.fasterxml.jackson.annotation.JsonProperty;
 /**
  * An expression that represent a term (label, description or alias).
  * The structure is slightly different from other expressions because
- * we need to call different methods on {@link ItemUpdate}.
+ * we need to call different methods on {@link ItemUpdateBuilder}.
  * 
  * @author Antonin Delpeuch
  *
@@ -46,7 +47,7 @@ public class WbNameDescExpr {
      * @param ctxt
      *       the evaluation context for the expression
      */
-    public void contributeTo(ItemUpdate item, ExpressionContext ctxt) {
+    public void contributeTo(ItemUpdateBuilder item, ExpressionContext ctxt) {
         try {
             MonolingualTextValue val = getValue().evaluate(ctxt);
             switch (getType()) {

extensions/wikidata/src/org/openrefine/wikidata/schema/WikibaseSchema.java

@@ -19,6 +19,8 @@ import com.google.refine.model.Project;
 import com.google.refine.model.Row;
 import org.openrefine.wikidata.schema.WbItemDocumentExpr;
 import org.openrefine.wikidata.schema.exceptions.SkipSchemaExpressionException;
+import org.openrefine.wikidata.updates.ItemUpdate;
+import org.openrefine.wikidata.updates.ItemUpdateBuilder;
 import org.openrefine.wikidata.qa.QAWarningStore;
 import org.openrefine.wikidata.schema.ExpressionContext;
 import org.openrefine.wikidata.utils.JacksonJsonizable;
@@ -73,7 +75,7 @@ public class WikibaseSchema implements OverlayModel {
      * @return
      */
     public List<ItemUpdate> evaluateItemDocuments(ExpressionContext ctxt) {
-        List<ItemUpdate> result = new ArrayList<ItemUpdate>();
+        List<ItemUpdate> result = new ArrayList<>();
         for (WbItemDocumentExpr expr : itemDocumentExprs) {
             
             try {
@@ -104,7 +106,7 @@ public class WikibaseSchema implements OverlayModel {
      * generating order (not merged yet).
      */
     public List<ItemUpdate> evaluate(Project project, Engine engine, QAWarningStore warningStore) {
-        List<ItemUpdate> result = new ArrayList<ItemUpdate>();
+        List<ItemUpdate> result = new ArrayList<>();
         FilteredRows filteredRows = engine.getAllFilteredRows();
         filteredRows.accept(project, new EvaluatingRowVisitor(result, warningStore));
         return result;

extensions/wikidata/src/org/openrefine/wikidata/updates/ItemUpdate.java

@@ -1,6 +1,7 @@
-package org.openrefine.wikidata.schema;
+package org.openrefine.wikidata.updates;
 
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
@@ -17,6 +18,9 @@ import org.wikidata.wdtk.datamodel.interfaces.MonolingualTextValue;
 import org.wikidata.wdtk.datamodel.interfaces.Statement;
 import org.wikidata.wdtk.datamodel.interfaces.StatementGroup;
 
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonIgnore;
+import com.fasterxml.jackson.annotation.JsonProperty;
 
 /**
  * A class to plan an update of an item, after evaluating the statements
@@ -26,12 +30,12 @@ import org.wikidata.wdtk.datamodel.interfaces.StatementGroup;
  * @author Antonin Delpeuch
  */
 public class ItemUpdate {
-    private ItemIdValue qid;
+    private final ItemIdValue qid;
-    private Set<Statement> addedStatements;
+    private final Set<Statement> addedStatements;
-    private Set<Statement> deletedStatements;
+    private final Set<Statement> deletedStatements;
-    private Set<MonolingualTextValue> labels;
+    private final Set<MonolingualTextValue> labels;
-    private Set<MonolingualTextValue> descriptions;
+    private final Set<MonolingualTextValue> descriptions;
-    private Set<MonolingualTextValue> aliases;
+    private final Set<MonolingualTextValue> aliases;
     
     /**
      * Constructor.
@@ -39,61 +43,42 @@ public class ItemUpdate {
      * @param qid
      *      the subject of the document. It can be a reconciled item value for new items.
      */
-    public ItemUpdate(ItemIdValue qid) {
+    @JsonCreator
+    public ItemUpdate(
+            @JsonProperty("subject") ItemIdValue qid,
+            @JsonProperty("addedStatements") Set<Statement> addedStatements,
+            @JsonProperty("deletedStatements") Set<Statement> deletedStatements,
+            @JsonProperty("labels") Set<MonolingualTextValue> labels,
+            @JsonProperty("descriptions") Set<MonolingualTextValue> descriptions,
+            @JsonProperty("addedAliases") Set<MonolingualTextValue> aliases) {
         Validate.notNull(qid);
         this.qid = qid;
-        this.addedStatements = new HashSet<>();
+        if(addedStatements == null) {
-        this.deletedStatements = new HashSet<Statement>();
+            addedStatements = Collections.emptySet();
-        this.labels = new HashSet<MonolingualTextValue>();
+        }
-        this.descriptions = new HashSet<MonolingualTextValue>();
+        this.addedStatements = addedStatements;
-        this.aliases = new HashSet<MonolingualTextValue>();
+        if(deletedStatements == null) {
-    }
+            deletedStatements = Collections.emptySet();
-    
+        }
-    /**
+        this.deletedStatements = deletedStatements;
-     * Mark a statement for insertion. If it matches an existing
+        if(labels == null) {
-     * statement, it will update the statement instead.
+            labels = Collections.emptySet();
-     * 
+        }
-     * @param statement
+        this.labels = labels;
-     *      the statement to add or update
+        if(descriptions == null) {
-     */
+            descriptions = Collections.emptySet();
-    public void addStatement(Statement statement) {
+        }
-        addedStatements.add(statement);
+        this.descriptions = descriptions;
-    }
+        if(aliases == null) {
-    
+            aliases = Collections.emptySet();
-    /**
+        }
-     * Mark a statement for deletion. If no such statement exists,
+        this.aliases = aliases;
-     * nothing will be deleted.
-     * 
-     * @param statement
-     *          the statement to delete
-     */
-    public void deleteStatement(Statement statement) {
-        deletedStatements.add(statement);
-    }
-    
-    /**
-     * Add a list of statement, as in {@link addStatement}.
-     * 
-     * @param statements
-     *        the statements to add
-     */
-    public void addStatements(Set<Statement> statements) {
-        addedStatements.addAll(statements);
-    }
-    
-    /**
-     * Delete a list of statements, as in {@link deleteStatement}.
-     * 
-     * @param statements
-     *          the statements to delete
-     */
-    public void deleteStatements(Set<Statement> statements) {
-        deletedStatements.addAll(statements);
     }
     
     /**
      * @return the subject of the item
      */
+    @JsonProperty("subject")
     public ItemIdValue getItemId() {
         return qid;
     }
@@ -101,6 +86,7 @@ public class ItemUpdate {
     /**
      * @return the set of all added statements
      */
+    @JsonProperty("addedStatements")
     public Set<Statement> getAddedStatements() {
         return addedStatements;
     }
@@ -108,74 +94,15 @@ public class ItemUpdate {
     /**
      * @return the list of all deleted statements
      */
+    @JsonProperty("deletedStatements")
     public Set<Statement> getDeletedStatements() {
         return deletedStatements;
     }
-
-    /**
-     * Merges all the changes in other into this instance.
-     * Both updates should have the same subject.
-     * 
-     * @param other
-     *          the other change that should be merged
-     */
-    public void merge(ItemUpdate other) {
-        Validate.isTrue(qid.equals(other.getItemId()));
-        addStatements(other.getAddedStatements());
-        deleteStatements(other.getDeletedStatements());
-        labels.addAll(other.getLabels());
-        descriptions.addAll(other.getDescriptions());
-        aliases.addAll(other.getAliases());
-    }
-
-    /**
-     * @return true when this change is empty
-     *          (no statements or terms changed)
-     */
-    public boolean isNull() {
-        return (addedStatements.isEmpty()
-                && deletedStatements.isEmpty()
-                && labels.isEmpty()
-                && descriptions.isEmpty()
-                && aliases.isEmpty());
-    }
-
-    /**
-     * Adds a label to the item. It will override any
-     * existing label in this language.
-     * 
-     * @param label
-     *      the label to add
-     */
-    public void addLabel(MonolingualTextValue label) {
-        labels.add(label);
-    }
-
-    /**
-     * Adds a description to the item. It will override any existing
-     * description in this language.
-     * 
-     * @param description
-     *      the description to add
-     */
-    public void addDescription(MonolingualTextValue description) {
-        descriptions.add(description);
-    }
-
-    /**
-     * Adds an alias to the item. It will be added to any existing
-     * aliases in that language.
-     * 
-     * @param alias
-     *      the alias to add
-     */
-    public void addAlias(MonolingualTextValue alias) {
-        aliases.add(alias);        
-    }
     
     /**
      * @return the list of updated labels
      */
+    @JsonProperty("labels")
     public Set<MonolingualTextValue> getLabels() {
         return labels;
     }
@@ -183,6 +110,7 @@ public class ItemUpdate {
     /**
      * @return the list of updated descriptions
      */
+    @JsonProperty("descriptions")
     public Set<MonolingualTextValue> getDescriptions() {
         return descriptions;
     }
@@ -190,10 +118,48 @@ public class ItemUpdate {
     /**
      * @return the list of updated aliases
      */
+    @JsonProperty("addedAliases")
     public Set<MonolingualTextValue> getAliases() {
         return aliases;
     }
     
+    /**
+     * @return true when this change is empty
+     *          (no statements or terms changed)
+     */
+    @JsonIgnore
+    public boolean isNull() {
+        return (addedStatements.isEmpty()
+                && deletedStatements.isEmpty()
+                && labels.isEmpty()
+                && descriptions.isEmpty()
+                && aliases.isEmpty());
+    }
+    
+    /**
+     * Merges all the changes in other into this instance.
+     * Both updates should have the same subject.
+     * 
+     * @param other
+     *          the other change that should be merged
+     */
+    public ItemUpdate merge(ItemUpdate other) {
+        Validate.isTrue(qid.equals(other.getItemId()));
+        Set<Statement> newAddedStatements = new HashSet<>(addedStatements);
+        newAddedStatements.addAll(other.getAddedStatements());
+        Set<Statement> newDeletedStatements = new HashSet<>(deletedStatements);
+        newDeletedStatements.addAll(other.getDeletedStatements());
+        Set<MonolingualTextValue> newLabels = new HashSet<>(labels);
+        newLabels.addAll(other.getLabels());
+        Set<MonolingualTextValue> newDescriptions = new HashSet<>(descriptions);
+        newDescriptions.addAll(other.getDescriptions());
+        Set<MonolingualTextValue> newAliases = new HashSet<>(aliases);
+        newAliases.addAll(other.getDescriptions());
+        return new ItemUpdate(
+                qid, newAddedStatements, newDeletedStatements,
+                newLabels, newDescriptions, newAliases);
+    }
+    
     /**
      * Group added statements in StatementGroups: useful if the
      * item is new.
@@ -215,7 +181,7 @@ public class ItemUpdate {
         }
         return result;
     }
-
+    
     /**
      * Group a list of ItemUpdates by subject: this is useful to make one single edit
      * per item.
@@ -224,7 +190,7 @@ public class ItemUpdate {
      * @return a map from item ids to merged ItemUpdate for that id
      */
     public static Map<EntityIdValue, ItemUpdate> groupBySubject(List<ItemUpdate> itemDocuments) {
-        Map<EntityIdValue, ItemUpdate> map = new HashMap<EntityIdValue, ItemUpdate>();
+        Map<EntityIdValue, ItemUpdate> map = new HashMap<>();
         for(ItemUpdate update : itemDocuments) {
             if (update.isNull()) {
                 continue;
@@ -233,38 +199,14 @@ public class ItemUpdate {
             ItemIdValue qid = update.getItemId();
             if (map.containsKey(qid)) {
                 ItemUpdate oldUpdate = map.get(qid);
-                oldUpdate.merge(update);
+                map.put(qid, oldUpdate.merge(update));
             } else {
                 map.put(qid, update);
             }
         }
         return map;
     }
-
+    
-    /**
-     * This should only be used when creating a new item.
-     * This ensures that we never add an alias without adding
-     * a label in the same language.
-     */
-    public void normalizeLabelsAndAliases() {
-        // Ensure that we are only adding aliases with labels
-        Set<String> labelLanguages = labels.stream()
-                .map(l -> l.getLanguageCode())
-                .collect(Collectors.toSet());
-        System.out.println(labelLanguages);
-
-        Set<MonolingualTextValue> filteredAliases = new HashSet<>();
-        for(MonolingualTextValue alias : aliases) {
-            if(!labelLanguages.contains(alias.getLanguageCode())) {
-                labelLanguages.add(alias.getLanguageCode());
-                labels.add(alias);
-            } else {
-                filteredAliases.add(alias);
-            }
-        }
-        aliases = filteredAliases;
-    }
-
     /**
      * Is this update about a new item?
      */
@@ -272,6 +214,31 @@ public class ItemUpdate {
         return "Q0".equals(getItemId().getId());
     }
     
+    /**
+     * This should only be used when creating a new item.
+     * This ensures that we never add an alias without adding
+     * a label in the same language.
+     */
+    public ItemUpdate normalizeLabelsAndAliases() {
+        // Ensure that we are only adding aliases with labels
+        Set<String> labelLanguages = labels.stream()
+                .map(l -> l.getLanguageCode())
+                .collect(Collectors.toSet());
+
+        Set<MonolingualTextValue> filteredAliases = new HashSet<>();
+        Set<MonolingualTextValue> newLabels = new HashSet<>(labels);
+        for(MonolingualTextValue alias : aliases) {
+            if(!labelLanguages.contains(alias.getLanguageCode())) {
+                labelLanguages.add(alias.getLanguageCode());
+                newLabels.add(alias);
+            } else {
+                filteredAliases.add(alias);
+            }
+        }
+        return new ItemUpdate(qid, addedStatements, deletedStatements,
+                newLabels, descriptions, filteredAliases);
+    }
+    
     @Override
     public boolean equals(Object other) {
         if(other == null || !ItemUpdate.class.isInstance(other)) {
@@ -310,4 +277,5 @@ public class ItemUpdate {
         builder.append("\n>");
         return builder.toString();
     }
+    
 }

extensions/wikidata/src/org/openrefine/wikidata/updates/ItemUpdateBuilder.java

@@ -0,0 +1,143 @@
+package org.openrefine.wikidata.updates;
+
+import java.util.Set;
+import java.util.HashSet;
+
+import org.jsoup.helper.Validate;
+import org.wikidata.wdtk.datamodel.interfaces.ItemIdValue;
+import org.wikidata.wdtk.datamodel.interfaces.MonolingualTextValue;
+import org.wikidata.wdtk.datamodel.interfaces.Statement;
+
+
+/**
+ * Constructs a {@link ItemUpdate} incrementally.
+ * 
+ * @author Antonin Delpeuch
+ *
+ */
+public class ItemUpdateBuilder {
+    private ItemIdValue qid;
+    private Set<Statement> addedStatements;
+    private Set<Statement> deletedStatements;
+    private Set<MonolingualTextValue> labels;
+    private Set<MonolingualTextValue> descriptions;
+    private Set<MonolingualTextValue> aliases;
+    private boolean built;
+    
+    /**
+     * Constructor.
+     * 
+     * @param qid
+     *      the subject of the document. It can be a reconciled item value for new items.
+     */
+    public ItemUpdateBuilder(ItemIdValue qid) {
+        Validate.notNull(qid);
+        this.qid = qid;
+        this.addedStatements = new HashSet<>();
+        this.deletedStatements = new HashSet<Statement>();
+        this.labels = new HashSet<MonolingualTextValue>();
+        this.descriptions = new HashSet<MonolingualTextValue>();
+        this.aliases = new HashSet<MonolingualTextValue>();
+        this.built = false;
+    }
+    
+    /**
+     * Mark a statement for insertion. If it matches an existing
+     * statement, it will update the statement instead.
+     * 
+     * @param statement
+     *      the statement to add or update
+     */
+    public ItemUpdateBuilder addStatement(Statement statement) {
+        Validate.isTrue(!built, "ItemUpdate has already been built");
+        addedStatements.add(statement);
+        return this;
+    }
+    
+    /**
+     * Mark a statement for deletion. If no such statement exists,
+     * nothing will be deleted.
+     * 
+     * @param statement
+     *          the statement to delete
+     */
+    public ItemUpdateBuilder deleteStatement(Statement statement) {
+        Validate.isTrue(!built, "ItemUpdate has already been built");
+        deletedStatements.add(statement);
+        return this;
+    }
+    
+    /**
+     * Add a list of statement, as in {@link addStatement}.
+     * 
+     * @param statements
+     *        the statements to add
+     */
+    public ItemUpdateBuilder addStatements(Set<Statement> statements) {
+        Validate.isTrue(!built, "ItemUpdate has already been built");
+        addedStatements.addAll(statements);
+        return this;
+    }
+    
+    /**
+     * Delete a list of statements, as in {@link deleteStatement}.
+     * 
+     * @param statements
+     *          the statements to delete
+     */
+    public ItemUpdateBuilder deleteStatements(Set<Statement> statements) {
+        Validate.isTrue(!built, "ItemUpdate has already been built");
+        deletedStatements.addAll(statements);
+        return this;
+    }
+
+    /**
+     * Adds a label to the item. It will override any
+     * existing label in this language.
+     * 
+     * @param label
+     *      the label to add
+     */
+    public ItemUpdateBuilder addLabel(MonolingualTextValue label) {
+        Validate.isTrue(!built, "ItemUpdate has already been built");
+        labels.add(label);
+        return this;
+    }
+
+    /**
+     * Adds a description to the item. It will override any existing
+     * description in this language.
+     * 
+     * @param description
+     *      the description to add
+     */
+    public ItemUpdateBuilder addDescription(MonolingualTextValue description) {
+        Validate.isTrue(!built, "ItemUpdate has already been built");
+        descriptions.add(description);
+        return this;
+    }
+
+    /**
+     * Adds an alias to the item. It will be added to any existing
+     * aliases in that language.
+     * 
+     * @param alias
+     *      the alias to add
+     */
+    public ItemUpdateBuilder addAlias(MonolingualTextValue alias) {
+        Validate.isTrue(!built, "ItemUpdate has already been built");
+        aliases.add(alias); 
+        return this;
+    }
+  
+    /**
+     * Constructs the {@link ItemUpdate}.
+     * @return
+     */
+    public ItemUpdate build() {
+        built = true;
+        return new ItemUpdate(qid, addedStatements, deletedStatements,
+                labels, descriptions, aliases);
+    }
+
+}

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

@@ -3,6 +3,8 @@ package org.openrefine.wikidata.schema;
 import java.util.Collections;
 
 import org.openrefine.wikidata.testing.JacksonSerializationTest;
+import org.openrefine.wikidata.updates.ItemUpdate;
+import org.openrefine.wikidata.updates.ItemUpdateBuilder;
 import org.testng.annotations.Test;
 import org.wikidata.wdtk.datamodel.helpers.Datamodel;
 import org.wikidata.wdtk.datamodel.interfaces.ItemIdValue;
@@ -39,9 +41,7 @@ public class WbItemDocumentExprTest extends WbExpressionTest<ItemUpdate> {
     @Test
     public void testEvaluate() {
         setRow(recon("Q3434"), "2010-07-23", "3.898,4.389", "my alias", recon("Q23"));
-        ItemUpdate result = new ItemUpdate(subject);
+        ItemUpdate result = new ItemUpdateBuilder(subject).addAlias(alias).addStatement(fullStatement).build();
-        result.addAlias(alias);
-        result.addStatement(fullStatement);
         evaluatesTo(result, expr);
     }
     
@@ -54,16 +54,14 @@ public class WbItemDocumentExprTest extends WbExpressionTest<ItemUpdate> {
     @Test
     public void testStatementSkipped() {
         setRow(recon("Q3434"), "2010-07-23", "3.898,invalid4.389", "my alias", recon("Q23"));
-        ItemUpdate result = new ItemUpdate(subject);
+        ItemUpdate result = new ItemUpdateBuilder(subject).addAlias(alias).build();
-        result.addAlias(alias);
         evaluatesTo(result, expr);
     }
     
     @Test
     public void testAliasSkipped() {
         setRow(recon("Q3434"), "2010-07-23", "3.898,4.389", "", recon("Q23"));
-        ItemUpdate result = new ItemUpdate(subject);
+        ItemUpdate result = new ItemUpdateBuilder(subject).addStatement(fullStatement).build();
-        result.addStatement(fullStatement);
         evaluatesTo(result, expr);
     }
     

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

@@ -6,6 +6,7 @@ import java.util.Collections;
 
 import org.openrefine.wikidata.testing.JacksonSerializationTest;
 import org.openrefine.wikidata.testing.TestingDataGenerator;
+import org.openrefine.wikidata.updates.ItemUpdateBuilder;
 import org.testng.annotations.Test;
 import org.wikidata.wdtk.datamodel.helpers.Datamodel;
 import org.wikidata.wdtk.datamodel.interfaces.ItemIdValue;
@@ -25,38 +26,38 @@ public class WbNameDescExprTest extends WbExpressionTest<MonolingualTextValue> {
     public void testContributeToLabel() {
         WbNameDescExpr labelExpr = new WbNameDescExpr(WbNameDescExpr.NameDescrType.LABEL,
                 TestingDataGenerator.getTestMonolingualExpr("fr", "français", "le croissant magnifique"));
-        ItemUpdate update = new ItemUpdate(subject);
+        ItemUpdateBuilder update = new ItemUpdateBuilder(subject);
         labelExpr.contributeTo(update, ctxt);
         assertEquals(Collections.singleton(Datamodel.makeMonolingualTextValue("le croissant magnifique", "fr")),
-                update.getLabels());
+                update.build().getLabels());
     }
 
     @Test
     public void testContributeToDescription() {
         WbNameDescExpr descriptionExpr = new WbNameDescExpr(WbNameDescExpr.NameDescrType.DESCRIPTION,
                 TestingDataGenerator.getTestMonolingualExpr("de", "Deutsch", "wunderschön"));
-        ItemUpdate update = new ItemUpdate(subject);
+        ItemUpdateBuilder update = new ItemUpdateBuilder(subject);
         descriptionExpr.contributeTo(update, ctxt);
         assertEquals(Collections.singleton(Datamodel.makeMonolingualTextValue("wunderschön", "de")),
-                update.getDescriptions());
+                update.build().getDescriptions());
     }
     
     @Test
     public void testContributeToAlias() {
         WbNameDescExpr aliasExpr = new WbNameDescExpr(WbNameDescExpr.NameDescrType.ALIAS,
                 TestingDataGenerator.getTestMonolingualExpr("en", "English", "snack"));
-        ItemUpdate update = new ItemUpdate(subject);
+        ItemUpdateBuilder update = new ItemUpdateBuilder(subject);
         aliasExpr.contributeTo(update, ctxt);
         assertEquals(Collections.singleton(Datamodel.makeMonolingualTextValue("snack", "en")),
-                update.getAliases());
+                update.build().getAliases());
     }
     
     @Test
     public void testSkipped() {
-        ItemUpdate update = new ItemUpdate(subject);
+        ItemUpdateBuilder update = new ItemUpdateBuilder(subject);
         setRow("");
         expr.contributeTo(update, ctxt);
-        assertEquals(new ItemUpdate(subject), update);
+        assertEquals(new ItemUpdateBuilder(subject).build(), update.build());
     }
     
     @Test

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

@@ -16,6 +16,8 @@ import org.json.JSONException;
 import org.json.JSONObject;
 import org.json.JSONWriter;
 import org.openrefine.wikidata.testing.TestingDataGenerator;
+import org.openrefine.wikidata.updates.ItemUpdate;
+import org.openrefine.wikidata.updates.ItemUpdateBuilder;
 import org.testng.annotations.Test;
 import org.wikidata.wdtk.datamodel.helpers.Datamodel;
 import org.wikidata.wdtk.datamodel.interfaces.Claim;
@@ -101,11 +103,9 @@ public class WikibaseSchemaTest extends RefineTest {
         Engine engine = new Engine(project);
         List<ItemUpdate> updates = schema.evaluate(project, engine);
         List<ItemUpdate> expected = new ArrayList<>();
-        ItemUpdate update1 = new ItemUpdate(qid1);
+        ItemUpdate update1 = new ItemUpdateBuilder(qid1).addStatement(statement1).build();
-        update1.addStatement(statement1);
         expected.add(update1);
-        ItemUpdate update2 = new ItemUpdate(qid2);
+        ItemUpdate update2 = new ItemUpdateBuilder(qid2).addStatement(statement2).build();
-        update2.addStatement(statement2);
         expected.add(update2);
         assertEquals(expected, updates);
     }

extensions/wikidata/tests/src/org/openrefine/wikidata/updates/ItemUpdateTest.java

@@ -1,4 +1,4 @@
-package org.openrefine.wikidata.schema;
+package org.openrefine.wikidata.updates;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
@@ -14,6 +14,7 @@ import java.util.Set;
 import java.util.stream.Collectors;
 
 import org.openrefine.wikidata.testing.TestingDataGenerator;
+import org.openrefine.wikidata.updates.ItemUpdateBuilder;
 import org.testng.annotations.Test;
 import org.wikidata.wdtk.datamodel.helpers.Datamodel;
 import org.wikidata.wdtk.datamodel.interfaces.Claim;
@@ -31,8 +32,7 @@ public class ItemUpdateTest {
     private ItemIdValue newSubject = TestingDataGenerator.makeNewItemIdValue(1234L, "new item");
     private ItemIdValue sameNewSubject = TestingDataGenerator.makeNewItemIdValue(1234L, "other new item");
     private ItemIdValue matchedSubject = TestingDataGenerator.makeMatchedItemIdValue("Q78", "well known item");
-    private ItemUpdate update = new ItemUpdate(existingSubject);
+
-    
     private PropertyIdValue pid1 = Datamodel.makeWikidataPropertyIdValue("P348");
     private PropertyIdValue pid2 = Datamodel.makeWikidataPropertyIdValue("P52");
     private Claim claim1 = Datamodel.makeClaim(existingSubject,
@@ -55,26 +55,29 @@ public class ItemUpdateTest {
     
     @Test(expectedExceptions=IllegalArgumentException.class)
     public void testCreateWithoutSubject() {
-        new ItemUpdate(null);
+        new ItemUpdateBuilder(null);
     }
     
     @Test
     public void testIsNull() {
+        ItemUpdate update = new ItemUpdateBuilder(existingSubject).build();
         assertTrue(update.isNull());
     }
     
     @Test
     public void testIsNew() {
-        ItemUpdate newUpdate = new ItemUpdate(newSubject);
+        ItemUpdate newUpdate = new ItemUpdateBuilder(newSubject).build();
         assertTrue(newUpdate.isNew());
+        ItemUpdate update = new ItemUpdateBuilder(existingSubject).build();
         assertFalse(update.isNew());
     }
     
     @Test
     public void testAddStatements() {
-        ItemUpdate update = new ItemUpdate(existingSubject);
+        ItemUpdate update = new ItemUpdateBuilder(existingSubject)
-        update.addStatement(statement1);
+           .addStatement(statement1)
-        update.addStatement(statement2);
+           .addStatement(statement2)
+           .build();
         assertEquals(Arrays.asList(statement1, statement2).stream().collect(Collectors.toSet()), 
                 update.getAddedStatements());
         assertEquals(statementGroups, update.getAddedStatementGroups().stream().collect(Collectors.toSet()));
@@ -82,39 +85,36 @@ public class ItemUpdateTest {
     
     @Test
     public void testDeleteStatements() {
-        ItemUpdate update = new ItemUpdate(existingSubject);
+        ItemUpdate update = new ItemUpdateBuilder(existingSubject)
-        update.deleteStatement(statement1);
+           .deleteStatement(statement1)
-        update.deleteStatement(statement2);
+           .deleteStatement(statement2)
+           .build();
         assertEquals(Arrays.asList(statement1, statement2).stream().collect(Collectors.toSet()),
                 update.getDeletedStatements());
     }
     
     @Test
     public void testMerge() {
-        ItemUpdate updateA = new ItemUpdate(existingSubject);
+        ItemUpdate updateA = new ItemUpdateBuilder(existingSubject).addStatement(statement1).build();
-        updateA.addStatement(statement1);
+        ItemUpdate updateB = new ItemUpdateBuilder(existingSubject).addStatement(statement2).build();
-        ItemUpdate updateB = new ItemUpdate(existingSubject);
-        updateB.addStatement(statement2);
         assertNotEquals(updateA, updateB);
-        updateA.merge(updateB);
+        ItemUpdate merged = updateA.merge(updateB);
         assertEquals(statementGroups,
-                updateA.getAddedStatementGroups().stream().collect(Collectors.toSet()));
+                merged.getAddedStatementGroups().stream().collect(Collectors.toSet()));
     }
     
     @Test
     public void testGroupBySubject() {
-        ItemUpdate updateA = new ItemUpdate(newSubject);
+        ItemUpdate updateA = new ItemUpdateBuilder(newSubject).addStatement(statement1).build();
-        updateA.addStatement(statement1);
+        ItemUpdate updateB = new ItemUpdateBuilder(sameNewSubject).addStatement(statement2).build();
-        ItemUpdate updateB = new ItemUpdate(sameNewSubject);
+        ItemUpdate updateC = new ItemUpdateBuilder(existingSubject).addLabel(label).build();
-        updateB.addStatement(statement2);
+        ItemUpdate updateD = new ItemUpdateBuilder(matchedSubject).build();
-        ItemUpdate updateC = new ItemUpdate(existingSubject);
-        updateC.addLabel(label);
-        ItemUpdate updateD = new ItemUpdate(matchedSubject);
         Map<EntityIdValue, ItemUpdate> grouped = ItemUpdate.groupBySubject(
                 Arrays.asList(updateA, updateB, updateC, updateD));
-        ItemUpdate mergedUpdate = new ItemUpdate(newSubject);
+        ItemUpdate mergedUpdate = new ItemUpdateBuilder(newSubject)
-        mergedUpdate.addStatement(statement1);
+                .addStatement(statement1)
-        mergedUpdate.addStatement(statement2);
+                .addStatement(statement2)
+                .build();
         Map<EntityIdValue, ItemUpdate> expected = new HashMap<>();
         expected.put(newSubject, mergedUpdate);
         expected.put(existingSubject, updateC);
@@ -125,15 +125,17 @@ public class ItemUpdateTest {
     public void testNormalizeTerms() {
         MonolingualTextValue aliasEn = Datamodel.makeMonolingualTextValue("alias", "en");
         MonolingualTextValue aliasFr = Datamodel.makeMonolingualTextValue("coucou", "fr");
-        ItemUpdate updateA = new ItemUpdate(newSubject);
+        ItemUpdate updateA = new ItemUpdateBuilder(newSubject)
-        updateA.addLabel(label);
+                .addLabel(label)
-        updateA.addAlias(aliasEn);
+                .addAlias(aliasEn)
-        updateA.addAlias(aliasFr);
+                .addAlias(aliasFr)
-        updateA.normalizeLabelsAndAliases();
+                .build();
-        ItemUpdate expectedUpdate = new ItemUpdate(newSubject);
+        ItemUpdate normalized = updateA.normalizeLabelsAndAliases();
-        expectedUpdate.addLabel(label);
+        ItemUpdate expectedUpdate = new ItemUpdateBuilder(newSubject)
-        expectedUpdate.addAlias(aliasEn);
+                .addLabel(label)
-        expectedUpdate.addLabel(aliasFr);
+                .addAlias(aliasEn)
-        assertEquals(expectedUpdate, updateA);
+                .addLabel(aliasFr)
+                .build();
+        assertEquals(expectedUpdate, normalized);
     }
 }