Add single value scrutinizer

extensions/wikidata/module/langs/translation-en.json

@@ -85,6 +85,10 @@
                 "disallowed-qualifiers": {
                         "title": "Disallowed qualifiers.",
                         "body": "Some of your qualifiers are incompatible with the statements that they qualify. Please check your schema."
+                },
+                "single-valued-property-added-more-than-once": {
+                        "title": "Single valued property added more than once.",
+                        "body": "A property that is expected to be used at most once on each item has been added multiple times on the same item."
                 }
        }
 }

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

@@ -42,16 +42,17 @@ public class ConstraintFetcher {
     
     public static String USED_ONLY_AS_REFERENCE_CONSTRAINT_QID = "Q21528959";
     
-    // The following constraints still need to be implemented:
-    
     public static String ALLOWED_QUALIFIERS_CONSTRAINT_QID = "Q21510851";
     public static String ALLOWED_QUALIFIERS_CONSTRAINT_PID = "P2306";
     
     public static String MANDATORY_QUALIFIERS_CONSTRAINT_QID = "Q21510856";
     public static String MANDATORY_QUALIFIERS_CONSTRAINT_PID = "P2306";
     
-    public static String SINGLE_VALUE_CONSRAINT_QID = "Q19474404";
-    public static String DISTINCT_VALUES_CONSRAINT_QID = "Q21502410";
+    public static String SINGLE_VALUE_CONSTRAINT_QID = "Q19474404";
+    public static String DISTINCT_VALUES_CONSTRAINT_QID = "Q21502410";
+    
+    // The following constraints still need to be implemented:
+    
     public static String TYPE_CONSTRAINT_QID = "Q21503250";
     
     
@@ -136,6 +137,20 @@ public class ConstraintFetcher {
         return null;
     }
     
+    /**
+     * Is this property expected to have at most one value per item?
+     */
+    public boolean hasSingleValue(PropertyIdValue pid) {
+        return getSingleConstraint(pid, SINGLE_VALUE_CONSTRAINT_QID) != null;
+    }
+    
+    /**
+     * Is this property expected to have distinct values?
+     */
+    public boolean hasDistinctValues(PropertyIdValue pid) {
+        return getSingleConstraint(pid, DISTINCT_VALUES_CONSTRAINT_QID) != null;
+    }
+    
     /**
      * Returns a single constraint for a particular type and a property, or null
      * if there is no such constraint

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

@@ -11,6 +11,7 @@ import org.openrefine.wikidata.qa.scrutinizers.NewItemScrutinizer;
 import org.openrefine.wikidata.qa.scrutinizers.QualifierCompatibilityScrutinizer;
 import org.openrefine.wikidata.qa.scrutinizers.RestrictedPositionScrutinizer;
 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.schema.ItemUpdate;
 
@@ -35,6 +36,7 @@ public class EditInspector {
         register(new UnsourcedScrutinizer());
         register(new RestrictedPositionScrutinizer());
         register(new QualifierCompatibilityScrutinizer());
+        register(new SingleValueScrutinizer());
     }
     
     /**

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

@@ -0,0 +1,39 @@
+package org.openrefine.wikidata.qa.scrutinizers;
+
+import java.util.HashSet;
+import java.util.Set;
+
+import org.openrefine.wikidata.qa.ConstraintFetcher;
+import org.openrefine.wikidata.schema.ItemUpdate;
+import org.wikidata.wdtk.datamodel.interfaces.PropertyIdValue;
+import org.wikidata.wdtk.datamodel.interfaces.Statement;
+
+/**
+ * For now this scrutinizer only checks for uniqueness at
+ * the item level (it ignores qualifiers and references).
+ * @author antonin
+ *
+ */
+public class SingleValueScrutinizer extends ItemEditScrutinizer {
+    
+    private ConstraintFetcher _fetcher;
+    
+    public SingleValueScrutinizer() {
+        _fetcher = new ConstraintFetcher();
+    }
+
+    @Override
+    public void scrutinize(ItemUpdate update) {
+        Set<PropertyIdValue> seenSingleProperties = new HashSet<>();
+        
+        for(Statement statement : update.getAddedStatements()) {
+            PropertyIdValue pid = statement.getClaim().getMainSnak().getPropertyId();
+            if (seenSingleProperties.contains(pid)) {
+                warning("single-valued-property-added-more-than-once");
+            } else if (_fetcher.hasSingleValue(pid)) {
+                seenSingleProperties.add(pid);
+            }
+        }
+    }
+
+}

extensions/wikidata/tests/src/org/openrefine/wikidata/qa/ConstraintFetcherTests.java

@@ -82,4 +82,16 @@ public class ConstraintFetcherTests {
         Assert.assertFalse(fetcher.mandatoryQualifiers(headOfGovernment).contains(endTime));
         Assert.assertNull(fetcher.allowedQualifiers(startTime));
     }
+    
+    @Test
+    public void testSingleValue() {
+        Assert.assertFalse(fetcher.hasSingleValue(headOfGovernment));
+        Assert.assertTrue(fetcher.hasSingleValue(gridId));
+    }
+    
+    @Test
+    public void testDistinctValues() {
+        Assert.assertFalse(fetcher.hasDistinctValues(partOf));
+        Assert.assertTrue(fetcher.hasDistinctValues(gridId));
+    }
 }