Update Wikidata-Toolkit to 0.12.1. (#4216)

* Update Wikidata-Toolkit to 0.12.1. Fixes #3202.

* Update groupId for WDTK

* Update our code after change of interfaces in WDTK.

extensions/wikidata/pom.xml

@@ -16,7 +16,7 @@
 
   <properties>
     <powermock.version>2.0.9</powermock.version>
-    <wdtk.version>0.12.0-SNAPSHOT</wdtk.version>
+    <wdtk.version>0.12.1</wdtk.version>
   </properties>
 
   <build>
@@ -127,7 +127,7 @@
       <scope>provided</scope>
     </dependency>
     <dependency>
-      <groupId>org.openrefine.dependencies.wdtk</groupId>
+      <groupId>org.wikidata.wdtk</groupId>
       <artifactId>wdtk-wikibaseapi</artifactId>
       <version>${wdtk.version}</version>
     </dependency>
@@ -137,12 +137,12 @@
       <version>${jackson.version}</version>
     </dependency>
     <dependency>
-      <groupId>org.openrefine.dependencies.wdtk</groupId>
+      <groupId>org.wikidata.wdtk</groupId>
       <artifactId>wdtk-datamodel</artifactId>
       <version>${wdtk.version}</version>
     </dependency>
     <dependency>
-      <groupId>org.openrefine.dependencies.wdtk</groupId>
+      <groupId>org.wikidata.wdtk</groupId>
       <artifactId>wdtk-util</artifactId>
       <version>${wdtk.version}</version>
     </dependency>

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

@@ -0,0 +1,52 @@
+package org.openrefine.wikidata.exporters;
+
+import org.wikidata.wdtk.datamodel.interfaces.NoValueSnak;
+import org.wikidata.wdtk.datamodel.interfaces.PropertyIdValue;
+import org.wikidata.wdtk.datamodel.interfaces.SnakVisitor;
+import org.wikidata.wdtk.datamodel.interfaces.SomeValueSnak;
+import org.wikidata.wdtk.datamodel.interfaces.ValueSnak;
+import org.wikidata.wdtk.datamodel.interfaces.ValueVisitor;
+
+/**
+ * Represents a snak in QuickStatements format.
+ * 
+ * @author Antonin Delpeuch
+ *
+ */
+public class QSSnakPrinter implements SnakVisitor<String> {
+    
+    protected final boolean reference;
+    protected final ValueVisitor<String> valuePrinter = new QSValuePrinter();
+    
+    /**
+     * @param reference indicates whether to print snaks as reference, or as main/qualifier snaks
+     */
+    public QSSnakPrinter(boolean reference) {
+        this.reference = reference;
+    }
+
+    @Override
+    public String visit(ValueSnak snak) {
+        String valStr = snak.getValue().accept(valuePrinter);
+        return toQS(snak.getPropertyId(), valStr);
+    }
+
+    @Override
+    public String visit(SomeValueSnak snak) {
+        return toQS(snak.getPropertyId(), "somevalue");
+    }
+
+    @Override
+    public String visit(NoValueSnak snak) {
+        return toQS(snak.getPropertyId(), "novalue");
+    }
+    
+    protected String toQS(PropertyIdValue property, String value) {
+        String pid = property.getId();
+        if (reference) {
+            pid = pid.replace('P', 'S');
+        }
+        return "\t" + pid + "\t" + value;
+    }
+
+}

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

@@ -42,8 +42,6 @@ import org.wikidata.wdtk.datamodel.interfaces.Reference;
 import org.wikidata.wdtk.datamodel.interfaces.Snak;
 import org.wikidata.wdtk.datamodel.interfaces.SnakGroup;
 import org.wikidata.wdtk.datamodel.interfaces.Statement;
-import org.wikidata.wdtk.datamodel.interfaces.Value;
-import org.wikidata.wdtk.datamodel.interfaces.ValueVisitor;
 
 import com.google.refine.browsing.Engine;
 import com.google.refine.exporters.WriterExporter;
@@ -56,7 +54,12 @@ public class QuickStatementsExporter implements WriterExporter {
     public static final String impossibleSchedulingErrorMessage = "This edit batch cannot be performed with QuickStatements due to the structure of its new items.";
     public static final String noSchemaErrorMessage = "No schema was provided. You need to align your project with Wikidata first.";
     
+    protected final QSSnakPrinter mainSnakPrinter;
+    protected final QSSnakPrinter referenceSnakPrinter;
+
     public QuickStatementsExporter() {
+        mainSnakPrinter = new QSSnakPrinter(false);
+        referenceSnakPrinter = new QSSnakPrinter(true);
     }
 
     @Override
@@ -148,19 +151,17 @@ public class QuickStatementsExporter implements WriterExporter {
             throws IOException {
         Claim claim = statement.getClaim();
 
-        Value val = claim.getValue();
+        Snak mainSnak = claim.getMainSnak();
-        ValueVisitor<String> vv = new QSValuePrinter();
+        String mainSnakQS = mainSnak.accept(mainSnakPrinter);
-        String targetValue = val.accept(vv);
-        if (targetValue != null) { // issue #2320
         if (!add) {
             // According to: https://www.wikidata.org/wiki/Help:QuickStatements#Removing_statements,
             // Removing statements won't be followed by qualifiers or references.
             writer.write("- ");
-                writer.write(qid + "\t" + pid + "\t" + targetValue);
+            writer.write(qid + mainSnakQS);
             writer.write("\n");
         } else { // add statements
             if (statement.getReferences().isEmpty()) {
-                    writer.write(qid + "\t" + pid + "\t" + targetValue);
+                writer.write(qid + mainSnakQS);
                 for (SnakGroup q : claim.getQualifiers()) {
                     translateSnakGroup(q, false, writer);
                 }
@@ -172,7 +173,7 @@ public class QuickStatementsExporter implements WriterExporter {
 
                 // So, to handle multiple references, we can duplicate the statement just with different references.
                 for (Reference r : statement.getReferences()) {
-                        writer.write(qid + "\t" + pid + "\t" + targetValue);
+                    writer.write(qid + mainSnakQS);
                     for (SnakGroup q : claim.getQualifiers()) {
                         translateSnakGroup(q, false, writer);
                     }
@@ -184,26 +185,15 @@ public class QuickStatementsExporter implements WriterExporter {
             }
         }
     }
-    }
 
     protected void translateSnakGroup(SnakGroup sg, boolean reference, Writer writer)
             throws IOException {
         for (Snak s : sg.getSnaks()) {
-            translateSnak(s, reference, writer);
-        }
-    }
-
-    protected void translateSnak(Snak s, boolean reference, Writer writer)
-            throws IOException {
-        String pid = s.getPropertyId().getId();
             if (reference) {
-            pid = pid.replace('P', 'S');
+                writer.write(s.accept(referenceSnakPrinter));
+            } else {
+                writer.write(s.accept(mainSnakPrinter));
             }
-        Value val = s.getValue();
-        ValueVisitor<String> vv = new QSValuePrinter();
-        String valStr = val.accept(vv);
-        if (valStr != null) {
-            writer.write("\t" + pid + "\t" + valStr);
         }
     }
 

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

@@ -5,6 +5,7 @@ import org.wikidata.wdtk.datamodel.interfaces.ItemIdValue;
 import org.wikidata.wdtk.datamodel.interfaces.Snak;
 import org.wikidata.wdtk.datamodel.interfaces.SnakGroup;
 import org.wikidata.wdtk.datamodel.interfaces.Statement;
+import org.wikidata.wdtk.datamodel.interfaces.ValueSnak;
 
 import java.util.HashSet;
 import java.util.List;
@@ -31,11 +32,11 @@ public class Constraint {
         List<SnakGroup> snakGroupList = statement.getClaim().getQualifiers();
         for(SnakGroup group : snakGroupList) {
             for (Snak snak : group.getSnaks()) {
-                if (group.getProperty().getId().equals(CONSTRAINT_STATUS)) {
+                if (group.getProperty().getId().equals(CONSTRAINT_STATUS) && snak instanceof ValueSnak) {
-                    constraintStatus = (ItemIdValue) snak.getValue();
+                    constraintStatus = (ItemIdValue) ((ValueSnak)snak).getValue();
                 }
-                else if (group.getProperty().getId().equals(CONSTRAINT_EXCEPTIONS)) {
+                else if (group.getProperty().getId().equals(CONSTRAINT_EXCEPTIONS) && snak instanceof ValueSnak) {
-                    constraintExceptions.add((EntityIdValue) snak.getValue());
+                    constraintExceptions.add((EntityIdValue) ((ValueSnak)snak).getValue());
                 }
             }
         }

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

@@ -7,6 +7,7 @@ import org.wikidata.wdtk.datamodel.interfaces.Snak;
 import org.wikidata.wdtk.datamodel.interfaces.SnakGroup;
 import org.wikidata.wdtk.datamodel.interfaces.Statement;
 import org.wikidata.wdtk.datamodel.interfaces.Value;
+import org.wikidata.wdtk.datamodel.interfaces.ValueSnak;
 
 import java.util.ArrayList;
 import java.util.HashMap;
@@ -32,11 +33,11 @@ public class ConflictsWithScrutinizer extends EditScrutinizer {
             this.itemList = new ArrayList<>();
             for(SnakGroup group : specs) {
                 for (Snak snak : group.getSnaks()) {
-                    if (group.getProperty().getId().equals(conflictsWithPropertyPid)){
+                    if (group.getProperty().getId().equals(conflictsWithPropertyPid) && snak instanceof ValueSnak) {
-                        pid = (PropertyIdValue) snak.getValue();
+                        pid = (PropertyIdValue) ((ValueSnak)snak).getValue();
                     }
-                    if (group.getProperty().getId().equals(itemOfPropertyConstraintPid)){
+                    if (group.getProperty().getId().equals(itemOfPropertyConstraintPid) && snak instanceof ValueSnak) {
-                        this.itemList.add(snak.getValue());
+                        this.itemList.add(((ValueSnak)snak).getValue());
                     }
                 }
             }
@@ -59,7 +60,11 @@ public class ConflictsWithScrutinizer extends EditScrutinizer {
         Map<PropertyIdValue, Set<Value>> propertyIdValueValueMap = new HashMap<>();
         for (Statement statement : update.getAddedStatements()){
             PropertyIdValue pid = statement.getClaim().getMainSnak().getPropertyId();
-            Value value = statement.getClaim().getMainSnak().getValue();
+            Value value = null;
+            Snak mainSnak = statement.getClaim().getMainSnak();
+            if (mainSnak instanceof ValueSnak) {
+                value = ((ValueSnak)mainSnak).getValue();
+            }
             Set<Value> values;
             if (value != null) {
                 if (propertyIdValueValueMap.containsKey(pid)) {

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

@@ -53,10 +53,13 @@ public class DifferenceWithinRangeScrutinizer extends EditScrutinizer {
     public void scrutinize(ItemUpdate update) {
         Map<PropertyIdValue, Value> propertyIdValueValueMap = new HashMap<>();
         for (Statement statement : update.getAddedStatements()){
-            PropertyIdValue pid = statement.getClaim().getMainSnak().getPropertyId();
+            Snak mainSnak = statement.getClaim().getMainSnak();
-            Value value = statement.getClaim().getMainSnak().getValue();
+            if (mainSnak instanceof ValueSnak) {
+                PropertyIdValue pid = mainSnak.getPropertyId();
+                Value value = ((ValueSnak)mainSnak).getValue();
                 propertyIdValueValueMap.put(pid, value);
             }
+        }
 
         for(PropertyIdValue propertyId : propertyIdValueValueMap.keySet()){
             List<Statement> statementList = _fetcher.getConstraintsByType(propertyId, differenceWithinRangeConstraintQid);

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

@@ -26,8 +26,10 @@ package org.openrefine.wikidata.qa.scrutinizers;
 import org.openrefine.wikidata.qa.QAWarning;
 import org.wikidata.wdtk.datamodel.interfaces.EntityIdValue;
 import org.wikidata.wdtk.datamodel.interfaces.PropertyIdValue;
+import org.wikidata.wdtk.datamodel.interfaces.Snak;
 import org.wikidata.wdtk.datamodel.interfaces.Statement;
 import org.wikidata.wdtk.datamodel.interfaces.Value;
+import org.wikidata.wdtk.datamodel.interfaces.ValueSnak;
 
 import java.util.HashMap;
 import java.util.List;
@@ -59,10 +61,11 @@ public class DistinctValuesScrutinizer extends StatementScrutinizer {
 
     @Override
     public void scrutinize(Statement statement, EntityIdValue entityId, boolean added) {
-        PropertyIdValue pid = statement.getClaim().getMainSnak().getPropertyId();
+        Snak mainSnak = statement.getClaim().getMainSnak();
+        PropertyIdValue pid = mainSnak.getPropertyId();
         List<Statement> statementList = _fetcher.getConstraintsByType(pid, distinctValuesConstraintQid);
-        if (!statementList.isEmpty()) {
+        if (!statementList.isEmpty() && mainSnak instanceof ValueSnak) {
-            Value mainSnakValue = statement.getClaim().getMainSnak().getValue();
+            Value mainSnakValue = ((ValueSnak)mainSnak).getValue();
             Map<Value, EntityIdValue> seen = _seenValues.get(pid);
             if (seen == null) {
                 seen = new HashMap<Value, EntityIdValue>();

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

@@ -32,6 +32,7 @@ import org.openrefine.wikidata.updates.ItemUpdate;
 import org.wikidata.wdtk.datamodel.interfaces.Snak;
 import org.wikidata.wdtk.datamodel.interfaces.SnakGroup;
 import org.wikidata.wdtk.datamodel.interfaces.Value;
+import org.wikidata.wdtk.datamodel.interfaces.ValueSnak;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -155,7 +156,9 @@ public abstract class EditScrutinizer {
         for (SnakGroup group : groups) {
             if (group.getProperty().getId().equals(pid)) {
                 for (Snak snak : group.getSnaks())
-                    results.add(snak.getValue());
+                    if (snak instanceof ValueSnak) {
+                        results.add(((ValueSnak)snak).getValue());
+                    }
             }
         }
         return results;

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

@@ -33,6 +33,7 @@ import org.wikidata.wdtk.datamodel.interfaces.SnakGroup;
 import org.wikidata.wdtk.datamodel.interfaces.Statement;
 import org.wikidata.wdtk.datamodel.interfaces.StringValue;
 import org.wikidata.wdtk.datamodel.interfaces.Value;
+import org.wikidata.wdtk.datamodel.interfaces.ValueSnak;
 
 import java.util.HashMap;
 import java.util.HashSet;
@@ -118,8 +119,8 @@ public class FormatScrutinizer extends SnakScrutinizer {
 
     @Override
     public void scrutinize(Snak snak, EntityIdValue entityId, boolean added) {
-        if (snak.getValue() instanceof StringValue) {
+        if (snak instanceof ValueSnak && ((ValueSnak)snak).getValue() instanceof StringValue) {
-            String value = ((StringValue) snak.getValue()).getString();
+            String value = ((StringValue) ((ValueSnak)snak).getValue()).getString();
             PropertyIdValue pid = snak.getPropertyId();
             Set<Pattern> patterns = getPattern(pid);
             for (Pattern pattern : patterns) {

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

@@ -27,9 +27,11 @@ import org.openrefine.wikidata.qa.QAWarning;
 import org.wikidata.wdtk.datamodel.interfaces.EntityIdValue;
 import org.wikidata.wdtk.datamodel.interfaces.ItemIdValue;
 import org.wikidata.wdtk.datamodel.interfaces.PropertyIdValue;
+import org.wikidata.wdtk.datamodel.interfaces.Snak;
 import org.wikidata.wdtk.datamodel.interfaces.SnakGroup;
 import org.wikidata.wdtk.datamodel.interfaces.Statement;
 import org.wikidata.wdtk.datamodel.interfaces.Value;
+import org.wikidata.wdtk.datamodel.interfaces.ValueSnak;
 
 import java.util.HashMap;
 import java.util.HashSet;
@@ -115,9 +117,13 @@ public class InverseConstraintScrutinizer extends StatementScrutinizer {
             return; // TODO support for deleted statements
         }
 
-        Value mainSnakValue = statement.getClaim().getMainSnak().getValue();
+        Snak mainSnak = statement.getClaim().getMainSnak();
+        if (! (mainSnak instanceof ValueSnak)) {
+            return;
+        }
+        Value mainSnakValue = ((ValueSnak)mainSnak).getValue();
         if (mainSnakValue instanceof ItemIdValue) {
-            PropertyIdValue pid = statement.getClaim().getMainSnak().getPropertyId();
+            PropertyIdValue pid = mainSnak.getPropertyId();
             PropertyIdValue inversePid = getInverseConstraint(pid);
             if (inversePid != null) {
                 EntityIdValue targetEntityId = (EntityIdValue) mainSnakValue;

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

@@ -7,6 +7,7 @@ import org.wikidata.wdtk.datamodel.interfaces.Snak;
 import org.wikidata.wdtk.datamodel.interfaces.SnakGroup;
 import org.wikidata.wdtk.datamodel.interfaces.Statement;
 import org.wikidata.wdtk.datamodel.interfaces.Value;
+import org.wikidata.wdtk.datamodel.interfaces.ValueSnak;
 
 import java.util.ArrayList;
 import java.util.HashMap;
@@ -35,11 +36,14 @@ public class ItemRequiresScrutinizer extends EditScrutinizer {
             this.itemList = new ArrayList<>();
             for(SnakGroup group : specs) {
                 for (Snak snak : group.getSnaks()) {
+                    if (! (snak instanceof ValueSnak)) {
+                        continue;
+                    }
                     if (group.getProperty().getId().equals(itemRequiresPropertyPid)){
-                        pid = (PropertyIdValue) snak.getValue();
+                        pid = (PropertyIdValue) ((ValueSnak)snak).getValue();
                     }
                     if (group.getProperty().getId().equals(itemOfPropertyConstraintPid)){
-                        this.itemList.add(snak.getValue());
+                        this.itemList.add(((ValueSnak)snak).getValue());
                     }
                 }
             }
@@ -60,10 +64,11 @@ public class ItemRequiresScrutinizer extends EditScrutinizer {
     public void scrutinize(ItemUpdate update) {
         Map<PropertyIdValue, Set<Value>> propertyIdValueValueMap = new HashMap<>();
         for (Statement statement : update.getAddedStatements()) {
-            PropertyIdValue pid = statement.getClaim().getMainSnak().getPropertyId();
+            Snak mainSnak = statement.getClaim().getMainSnak();
-            Value value = statement.getClaim().getMainSnak().getValue();
+            PropertyIdValue pid = mainSnak.getPropertyId();
             Set<Value> values;
-            if (value != null) {
+            if (mainSnak instanceof ValueSnak) {
+                Value value = ((ValueSnak)mainSnak).getValue();
                 if (propertyIdValueValueMap.containsKey(pid)) {
                     values = propertyIdValueValueMap.get(pid);
                 } else {

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

@@ -9,6 +9,7 @@ import org.wikidata.wdtk.datamodel.interfaces.Snak;
 import org.wikidata.wdtk.datamodel.interfaces.SnakGroup;
 import org.wikidata.wdtk.datamodel.interfaces.Statement;
 import org.wikidata.wdtk.datamodel.interfaces.Value;
+import org.wikidata.wdtk.datamodel.interfaces.ValueSnak;
 
 import java.util.List;
 import java.util.Set;
@@ -58,9 +59,9 @@ public class QuantityScrutinizer extends SnakScrutinizer {
 
     @Override
     public void scrutinize(Snak snak, EntityIdValue entityId, boolean added) {
-        if (snak.getValue() instanceof QuantityValue && added) {
+        if (snak instanceof ValueSnak && ((ValueSnak)snak).getValue() instanceof QuantityValue && added) {
             PropertyIdValue pid = snak.getPropertyId();
-            QuantityValue value = (QuantityValue)snak.getValue();
+            QuantityValue value = (QuantityValue)((ValueSnak)snak).getValue();
 
             if(!_fetcher.getConstraintsByType(pid, noBoundsConstraintQid).isEmpty() && (value.getUpperBound() != null || value.getLowerBound() != null)) {
                 QAWarning issue = new QAWarning(boundsDisallowedType, pid.getId(), QAWarning.Severity.IMPORTANT, 1);

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

@@ -7,6 +7,7 @@ import org.wikidata.wdtk.datamodel.interfaces.Snak;
 import org.wikidata.wdtk.datamodel.interfaces.SnakGroup;
 import org.wikidata.wdtk.datamodel.interfaces.Statement;
 import org.wikidata.wdtk.datamodel.interfaces.Value;
+import org.wikidata.wdtk.datamodel.interfaces.ValueSnak;
 
 import java.util.List;
 import java.util.Set;
@@ -57,7 +58,10 @@ public class RestrictedValuesScrutinizer extends SnakScrutinizer {
     @Override
     public void scrutinize(Snak snak, EntityIdValue entityId, boolean added) {
         PropertyIdValue pid = snak.getPropertyId();
-        Value value = snak.getValue();
+        Value value = null;
+        if (snak instanceof ValueSnak) {
+            value = ((ValueSnak)snak).getValue();
+        }
         List<Statement> allowedValueConstraintDefinitions = _fetcher.getConstraintsByType(pid, allowedValuesConstraintQid);
         List<Statement> disallowedValueConstraintDefinitions = _fetcher.getConstraintsByType(pid, disallowedValuesConstraintQid);
         Set<Value> allowedValues = null, disallowedValues = null;

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

@@ -26,6 +26,7 @@ package org.openrefine.wikidata.qa.scrutinizers;
 import org.openrefine.wikidata.qa.QAWarning;
 import org.wikidata.wdtk.datamodel.interfaces.EntityIdValue;
 import org.wikidata.wdtk.datamodel.interfaces.Snak;
+import org.wikidata.wdtk.datamodel.interfaces.ValueSnak;
 
 /**
  * A scrutinizer that checks for self-referential statements. These statements
@@ -40,7 +41,7 @@ public class SelfReferentialScrutinizer extends SnakScrutinizer {
 
     @Override
     public void scrutinize(Snak snak, EntityIdValue entityId, boolean added) {
-        if (entityId.equals(snak.getValue())) {
+        if (snak instanceof ValueSnak && entityId.equals(((ValueSnak)snak).getValue())) {
             QAWarning issue = new QAWarning(type, null, QAWarning.Severity.WARNING, 1);
             issue.setProperty("example_entity", entityId);
             addIssue(issue);

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

@@ -8,6 +8,7 @@ import org.wikidata.wdtk.datamodel.interfaces.Snak;
 import org.wikidata.wdtk.datamodel.interfaces.SnakGroup;
 import org.wikidata.wdtk.datamodel.interfaces.Statement;
 import org.wikidata.wdtk.datamodel.interfaces.Value;
+import org.wikidata.wdtk.datamodel.interfaces.ValueSnak;
 
 import java.util.ArrayList;
 import java.util.HashMap;
@@ -30,11 +31,14 @@ public class UseAsQualifierScrutinizer extends EditScrutinizer {
             this.itemList = new ArrayList<>();
             for(SnakGroup group : specs) {
                 for (Snak snak : group.getSnaks()) {
+                    if (! (snak instanceof ValueSnak)) {
+                        continue;
+                    }
                     if (group.getProperty().getId().equals(property)){
-                        pid = (PropertyIdValue) snak.getValue();
+                        pid = (PropertyIdValue) ((ValueSnak)snak).getValue();
                     }
                     if (group.getProperty().getId().equals(itemOfPropertyConstraintPid)){
-                        this.itemList.add(snak.getValue());
+                        this.itemList.add(((ValueSnak)snak).getValue());
                     }
                 }
             }
@@ -58,15 +62,18 @@ public class UseAsQualifierScrutinizer extends EditScrutinizer {
             List<SnakGroup> qualifiersList = statement.getClaim().getQualifiers();
 
             for(SnakGroup qualifier : qualifiersList) {
-                PropertyIdValue qualifierPid = Datamodel.makeWikidataPropertyIdValue(qualifier.getProperty().getId());
+                PropertyIdValue qualifierPid = qualifier.getProperty();
                 List<Value> itemList;
                 for (Snak snak : qualifier.getSnaks()) {
+                    if (!(snak instanceof ValueSnak)) {
+                        continue;
+                    }
                     if (qualifiersMap.containsKey(qualifierPid)){
                         itemList = qualifiersMap.get(qualifierPid);
-                    }else {
+                    } else {
                         itemList = new ArrayList<>();
                     }
-                    itemList.add(snak.getValue());
+                    itemList.add(((ValueSnak)snak).getValue());
                     qualifiersMap.put(qualifierPid, itemList);
                 }
             }

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

@@ -28,6 +28,7 @@ import org.wikidata.wdtk.datamodel.interfaces.EntityIdValue;
 import org.wikidata.wdtk.datamodel.interfaces.MonolingualTextValue;
 import org.wikidata.wdtk.datamodel.interfaces.Snak;
 import org.wikidata.wdtk.datamodel.interfaces.Value;
+import org.wikidata.wdtk.datamodel.interfaces.ValueSnak;
 
 /**
  * A scrutinizer that inspects the values of snaks and terms
@@ -56,7 +57,9 @@ public abstract class ValueScrutinizer extends SnakScrutinizer {
 
     @Override
     public void scrutinize(Snak snak, EntityIdValue entityId, boolean added) {
-        scrutinize(snak.getValue());
+        if (snak instanceof ValueSnak) {
+            scrutinize(((ValueSnak)snak).getValue());
+        }
     }
 
 }

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

@@ -92,7 +92,7 @@ public class WbQuantityExpr implements WbExpression<QuantityValue> {
 
         if (getUnitExpr() != null) {
             ItemIdValue unit = getUnitExpr().evaluate(ctxt);
-            return Datamodel.makeQuantityValue(parsedAmount, lowerBound, upperBound, unit.getIri());
+            return Datamodel.makeQuantityValue(parsedAmount, lowerBound, upperBound, unit);
         }
 
         return Datamodel.makeQuantityValue(parsedAmount, lowerBound, upperBound);

extensions/wikidata/src/org/openrefine/wikidata/updates/scheduler/PointerExtractor.java

@@ -40,6 +40,7 @@ import org.wikidata.wdtk.datamodel.interfaces.StringValue;
 import org.wikidata.wdtk.datamodel.interfaces.TimeValue;
 import org.wikidata.wdtk.datamodel.interfaces.UnsupportedValue;
 import org.wikidata.wdtk.datamodel.interfaces.Value;
+import org.wikidata.wdtk.datamodel.interfaces.ValueSnak;
 import org.wikidata.wdtk.datamodel.interfaces.ValueVisitor;
 
 /**
@@ -101,7 +102,9 @@ public class PointerExtractor implements ValueVisitor<Set<ReconItemIdValue>> {
     public Set<ReconItemIdValue> extractPointers(Snak snak) {
         Set<ReconItemIdValue> result = new HashSet<>();
         result.addAll(extractPointers(snak.getPropertyId()));
-        result.addAll(extractPointers(snak.getValue()));
+        if (snak instanceof ValueSnak) {
+            result.addAll(extractPointers(((ValueSnak)snak).getValue()));
+        }
         return result;
     }
 

extensions/wikidata/src/org/openrefine/wikidata/utils/SnakUtils.java

@@ -0,0 +1,42 @@
+package org.openrefine.wikidata.utils;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+import org.wikidata.wdtk.datamodel.helpers.Datamodel;
+import org.wikidata.wdtk.datamodel.interfaces.PropertyIdValue;
+import org.wikidata.wdtk.datamodel.interfaces.Snak;
+import org.wikidata.wdtk.datamodel.interfaces.SnakGroup;
+
+public class SnakUtils {
+
+    /**
+     * Groups snaks into a list of snak groups.
+     * The order of the first snaks in each group is preserved.
+     * 
+     * @param snaks
+     * @return
+     */
+    public static List<SnakGroup> groupSnaks(List<Snak> snaks) {
+        Map<PropertyIdValue, List<Snak>> snakGroups = new HashMap<>();
+        List<PropertyIdValue> propertyOrder = new ArrayList<PropertyIdValue>();
+        for (Snak snak : snaks) {
+            List<Snak> existingSnaks = snakGroups.get(snak.getPropertyId());
+            if(existingSnaks == null) {
+                existingSnaks = new ArrayList<Snak>();
+                snakGroups.put(snak.getPropertyId(), existingSnaks);
+                propertyOrder.add(snak.getPropertyId());
+            }
+            if (!existingSnaks.contains(snak)) {
+                existingSnaks.add(snak);
+            }
+        }
+        return propertyOrder.stream()
+                .map(pid -> Datamodel.makeSnakGroup(snakGroups.get(pid)))
+                .collect(Collectors.toList());
+    }
+
+}

extensions/wikidata/tests/src/org/openrefine/wikidata/exporters/QSSnakPrinterTest.java

@@ -0,0 +1,40 @@
+package org.openrefine.wikidata.exporters;
+
+import org.testng.Assert;
+import org.testng.annotations.Test;
+import org.wikidata.wdtk.datamodel.helpers.Datamodel;
+import org.wikidata.wdtk.datamodel.interfaces.ItemIdValue;
+import org.wikidata.wdtk.datamodel.interfaces.PropertyIdValue;
+import org.wikidata.wdtk.datamodel.interfaces.Snak;
+
+public class QSSnakPrinterTest {
+
+    private QSSnakPrinter refPrinter = new QSSnakPrinter(true);
+    private QSSnakPrinter mainPrinter = new QSSnakPrinter(false);
+    private PropertyIdValue pid = Datamodel.makeWikidataPropertyIdValue("P123");
+    private ItemIdValue qid = Datamodel.makeWikidataItemIdValue("Q456");
+    
+    @Test
+    public void testReferenceValueSnak() {
+        Snak snak = Datamodel.makeValueSnak(pid, qid);
+        Assert.assertEquals(snak.accept(refPrinter), "\tS123\tQ456");
+    }
+    
+    @Test
+    public void testMainValueSnak() {
+        Snak snak = Datamodel.makeValueSnak(pid, qid);
+        Assert.assertEquals(snak.accept(mainPrinter), "\tP123\tQ456");
+    }
+    
+    @Test
+    public void testReferenceNoValueSnak() {
+        Snak snak = Datamodel.makeNoValueSnak(pid);
+        Assert.assertEquals(snak.accept(refPrinter), "\tS123\tnovalue");
+    }
+    
+    @Test
+    public void testMainSomeValueSnak() {
+        Snak snak = Datamodel.makeSomeValueSnak(pid);
+        Assert.assertEquals(snak.accept(mainPrinter), "\tP123\tsomevalue");
+    }
+}

extensions/wikidata/tests/src/org/openrefine/wikidata/exporters/QSValuePrinterTest.java

@@ -92,25 +92,25 @@ public class QSValuePrinterTest {
 
     @Test
     public void printSimpleQuantityValue() {
-        assertPrints("10.00", Datamodel.makeQuantityValue(new BigDecimal("10.00"), null, null, "1"));
+        assertPrints("10.00", Datamodel.makeQuantityValue(new BigDecimal("10.00")));
     }
 
     @Test
     public void printQuantityValueWithUnit() {
-        assertPrints("10.00U11573", Datamodel.makeQuantityValue(new BigDecimal("10.00"), null, null,
+        assertPrints("10.00U11573", Datamodel.makeQuantityValue(new BigDecimal("10.00"),
-                "http://www.wikidata.org/entity/Q11573"));
+                Datamodel.makeWikidataItemIdValue("Q11573")));
     }
 
     @Test
     public void printQuantityValueWithBounds() {
         assertPrints("10.00[9.0,11.05]", Datamodel.makeQuantityValue(new BigDecimal("10.00"), new BigDecimal("9.0"),
-                new BigDecimal("11.05"), "1"));
+                new BigDecimal("11.05")));
     }
 
     @Test
     public void printFullQuantity() {
         assertPrints("10.00[9.0,11.05]U11573", Datamodel.makeQuantityValue(new BigDecimal("10.00"),
-                new BigDecimal("9.0"), new BigDecimal("11.05"), "http://www.wikidata.org/entity/Q11573"));
+                new BigDecimal("9.0"), new BigDecimal("11.05"), Datamodel.makeWikidataItemIdValue("Q11573")));
     }
 
     // String values

extensions/wikidata/tests/src/org/openrefine/wikidata/exporters/QuickStatementsExporterTest.java

@@ -134,6 +134,30 @@ public class QuickStatementsExporterTest extends WikidataRefineTest {
         assertEquals("Q1377\tP38\tQ865528\tP38\tQ1377\n", export(update));
     }
     
+    @Test
+    public void testSomeValue()
+            throws IOException {
+        PropertyIdValue pid = Datamodel.makeWikidataPropertyIdValue("P123");
+        Claim claim = Datamodel.makeClaim(qid1, Datamodel.makeSomeValueSnak(pid), Collections.emptyList());
+        Statement statement = Datamodel.makeStatement(claim, Collections.emptyList(), StatementRank.NORMAL, "");
+
+        ItemUpdate update = new ItemUpdateBuilder(qid1).addStatement(statement).build();
+
+        assertEquals("Q1377\tP123\tsomevalue\n", export(update));
+    }
+    
+    @Test
+    public void testNoValue()
+            throws IOException {
+        PropertyIdValue pid = Datamodel.makeWikidataPropertyIdValue("P123");
+        Claim claim = Datamodel.makeClaim(qid1, Datamodel.makeNoValueSnak(pid), Collections.emptyList());
+        Statement statement = Datamodel.makeStatement(claim, Collections.emptyList(), StatementRank.NORMAL, "");
+
+        ItemUpdate update = new ItemUpdateBuilder(qid1).addStatement(statement).build();
+
+        assertEquals("Q1377\tP123\tnovalue\n", export(update));
+    }
+
     /**
      * issue #2320
      *

extensions/wikidata/tests/src/org/openrefine/wikidata/qa/scrutinizers/QuantityScrutinizerTest.java

@@ -45,7 +45,7 @@ public class QuantityScrutinizerTest extends ValueScrutinizerTest{
             new BigDecimal("1.545"));
     
     private QuantityValue wrongUnitValue = Datamodel.makeQuantityValue(
-            new BigDecimal("1.234"), "Q346721");
+            new BigDecimal("1.234"), Datamodel.makeWikidataItemIdValue("Q346721"));
     
     private QuantityValue goodUnitValue = Datamodel.makeQuantityValue(
             new BigDecimal("1.234"), (ItemIdValue) allowedUnit);

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

@@ -44,13 +44,13 @@ public class WbQuantityExprTest extends WbExpressionTest<QuantityValue> {
     public void testWithoutUnit()
             throws SkipSchemaExpressionException {
         setRow("4.00");
-        evaluatesTo(Datamodel.makeQuantityValue(new BigDecimal("4.00"), null, null, "1"), exprWithoutUnit);
+        evaluatesTo(Datamodel.makeQuantityValue(new BigDecimal("4.00")), exprWithoutUnit);
     }
     
     @Test
     public void testOverflow() {
     	setRow(14341937500d);
-    	evaluatesTo(Datamodel.makeQuantityValue(new BigDecimal("14341937500"), null, null, "1"), exprWithoutUnit);
+    	evaluatesTo(Datamodel.makeQuantityValue(new BigDecimal("14341937500")), exprWithoutUnit);
     }
 
     @Test
@@ -64,7 +64,7 @@ public class WbQuantityExprTest extends WbExpressionTest<QuantityValue> {
             throws SkipSchemaExpressionException {
         setRow("56.094", recon("Q42"));
         evaluatesTo(
-                Datamodel.makeQuantityValue(new BigDecimal("56.094"), null, null, "http://www.wikidata.org/entity/Q42"),
+                Datamodel.makeQuantityValue(new BigDecimal("56.094"), Datamodel.makeWikidataItemIdValue("Q42")),
                 exprWithUnit);
     }
 

extensions/wikidata/tests/src/org/openrefine/wikidata/updates/scheduler/PointerExtractorTest.java

@@ -73,7 +73,7 @@ public class PointerExtractorTest {
         assertEmpty(Datamodel.makeMonolingualTextValue("srtu", "en"));
         assertEmpty(Datamodel.makeWikidataPropertyIdValue("P78"));
         assertEmpty(Datamodel.makeQuantityValue(new BigDecimal("898")));
-        assertEmpty(Datamodel.makeQuantityValue(new BigDecimal("7.87"), "http://www.wikidata.org/entity/Q34"));
+        assertEmpty(Datamodel.makeQuantityValue(new BigDecimal("7.87"), Datamodel.makeWikidataItemIdValue("Q34")));
         assertEmpty(Datamodel.makeTimeValue(1898, (byte) 2, (byte) 3, TimeValue.CM_GREGORIAN_PRO));
         assertEmpty(mock(UnsupportedValue.class));
     }

extensions/wikidata/tests/src/org/openrefine/wikidata/utils/SnakUtilsTests.java

@@ -0,0 +1,40 @@
+package org.openrefine.wikidata.utils;
+
+import java.util.Arrays;
+import java.util.List;
+
+import org.testng.Assert;
+import org.testng.annotations.Test;
+import org.wikidata.wdtk.datamodel.helpers.Datamodel;
+import org.wikidata.wdtk.datamodel.interfaces.PropertyIdValue;
+import org.wikidata.wdtk.datamodel.interfaces.Snak;
+import org.wikidata.wdtk.datamodel.interfaces.SnakGroup;
+import org.wikidata.wdtk.datamodel.interfaces.StringValue;
+
+public class SnakUtilsTests {
+    
+    PropertyIdValue pidA = Datamodel.makeWikidataPropertyIdValue("P1");
+    PropertyIdValue pidB = Datamodel.makeWikidataPropertyIdValue("P2");
+    PropertyIdValue pidC = Datamodel.makeWikidataPropertyIdValue("P3");
+    StringValue value1 = Datamodel.makeStringValue("value1");
+    StringValue value2 = Datamodel.makeStringValue("value2");
+    
+    Snak snakA1 = Datamodel.makeValueSnak(pidA, value1);
+    Snak snakA2 = Datamodel.makeValueSnak(pidA, value2);
+    Snak snakB1 = Datamodel.makeValueSnak(pidB, value1);
+    Snak snakC1 = Datamodel.makeValueSnak(pidC, value1);
+    Snak snakC2 = Datamodel.makeValueSnak(pidC, value2);
+    
+    @Test
+    public void testGroupSnaks() {
+        List<SnakGroup> snakGroups = SnakUtils.groupSnaks(Arrays.asList(snakA2, snakB1, snakC1, snakA1, snakC2));
+        
+        List<SnakGroup> expected = Arrays.asList(
+                Datamodel.makeSnakGroup(Arrays.asList(snakA2, snakA1)),
+                Datamodel.makeSnakGroup(Arrays.asList(snakB1)),
+                Datamodel.makeSnakGroup(Arrays.asList(snakC1, snakC2))
+                );
+        
+        Assert.assertEquals(snakGroups, expected);
+    }
+}