Fix GraphView property-access for 3.2

Author: jexp

core/src/main/java/org/neo4j/graphalgo/core/Kernel.java

@@ -5,6 +5,7 @@
 import org.neo4j.cursor.Cursor;
 import org.neo4j.kernel.api.ReadOperations;
 import org.neo4j.kernel.api.Statement;
+import org.neo4j.kernel.api.StatementConstants;
 import org.neo4j.kernel.api.exceptions.EntityNotFoundException;
 import org.neo4j.kernel.impl.api.store.RelationshipIterator;
 import org.neo4j.kernel.impl.locking.Lock;
@@ -360,6 +361,14 @@ public Lock lock() {
             return item.lock();
         }
 
+        public Object propertyValue(int propertyId) {
+            try {
+                return propertyId == StatementConstants.NO_SUCH_PROPERTY_KEY ? null : readOperations.nodeGetProperty(item.id(), propertyId);
+            } catch (EntityNotFoundException e) {
+                return null;
+            }
+        }
+
         PropertyItemCursor cursor = new PropertyItemCursor();
         public Cursor<PropertyItem> property(int propertyId) {
             try {
@@ -384,6 +393,13 @@ public RelationshipItem(org.neo4j.storageengine.api.RelationshipItem item) {
         public RelationshipItem() {
         }
 
+        public Object propertyValue(int propertyId) {
+            try {
+                return propertyId == StatementConstants.NO_SUCH_PROPERTY_KEY ? null : readOperations.relationshipGetProperty(item.id(), propertyId);
+            } catch (EntityNotFoundException e) {
+                return null;
+            }
+        }
         public Cursor<PropertyItem> property(int propertyId) {
             try {
                 cursor.propertyId = propertyId;

core/src/main/java/org/neo4j/graphalgo/core/neo4jview/GraphView.java

@@ -17,6 +17,7 @@
 import org.neo4j.kernel.impl.core.ThreadToStatementContextBridge;
 import org.neo4j.kernel.internal.GraphDatabaseAPI;
 import org.neo4j.storageengine.api.NodeItem;
+import org.neo4j.storageengine.api.PropertyItem;
 import org.neo4j.storageengine.api.RelationshipItem;
 
 import java.util.Arrays;
@@ -91,8 +92,11 @@ public void forEachRelationship(int nodeId, Direction direction, WeightedRelatio
             long relId = RawValues.combineIntInt(
                     (int) item.startNode(),
                     (int) item.endNode());
-            double weight = (propertyKey == StatementConstants.NO_SUCH_PROPERTY_KEY) ? propertyDefaultWeight :
-                    ((Number) item.property(propertyKey)).doubleValue();
+            double weight = propertyDefaultWeight;
+            Object value = item.propertyValue(propertyKey);
+            if (value instanceof Number) {
+                weight = ((Number) value).doubleValue();
+            }
 
             consumer.accept(
                     nodeId,