GH-640 - Store visited nodes under their native graph id if possible. (…

…#642)

This change tries to store visited nodes under their native graph id in the compile context if possible. Thus, they are recognized even when a user uses a different instance of the same entity for persisting state.

This fixes #640.

core/src/main/java/org/neo4j/ogm/context/EntityGraphMapper.java

@@ -58,7 +58,7 @@ public class EntityGraphMapper implements EntityMapper {
 
     private final MetaData metaData;
     private final MappingContext mappingContext;
-    private final Compiler compiler = new MultiStatementCypherCompiler();
+    private final Compiler compiler;
     /**
      * Default supplier for write protection: Always write all the stuff.
      */
@@ -73,6 +73,7 @@ public class EntityGraphMapper implements EntityMapper {
     public EntityGraphMapper(MetaData metaData, MappingContext mappingContext) {
         this.metaData = metaData;
         this.mappingContext = mappingContext;
+        this.compiler = new MultiStatementCypherCompiler(mappingContext::nativeId);
     }
 
     public void addWriteProtection(BiFunction<WriteProtectionTarget, Class<?>, Predicate<Object>> writeProtectionSupplier) {

core/src/main/java/org/neo4j/ogm/cypher/compiler/CypherContext.java

@@ -38,6 +38,10 @@
  */
 public class CypherContext implements CompileContext {
 
+    /**
+     * Stores the the builder and the horizon of visited objects. The key is either the native graph id of the entity
+     * if the id is available (that is not null and greater 0L) or otherwise the entity itself.
+     */
     private final Map<Object, NodeBuilderHorizonPair> visitedObjects = new IdentityHashMap<>();
     private final Set<Long> visitedRelationshipEntities = new HashSet<>();
 
@@ -52,18 +56,26 @@ public class CypherContext implements CompileContext {
 
     private final Compiler compiler;
 
-    public CypherContext(Compiler compiler) {
+    private final Function<Object, Long> nativeIdProvider;
+
+    public CypherContext(Compiler compiler, Function<Object, Long> nativeIdProvider) {
         this.compiler = compiler;
+        this.nativeIdProvider = nativeIdProvider;
+    }
+
+    private Object getIdentity(Object entity) {
+        Long nativeId = this.nativeIdProvider.apply(entity);
+        return (nativeId == null || nativeId < 0) ? entity : nativeId;
     }
 
     public boolean visited(Object entity, int horizon) {
-        NodeBuilderHorizonPair pair = visitedObjects.get(entity);
+        NodeBuilderHorizonPair pair = visitedObjects.get(getIdentity(entity));
         return pair != null && (horizon < 0 || pair.getHorizon() > horizon);
     }
 
     @Override
     public void visit(Object entity, NodeBuilder nodeBuilder, int horizon) {
-        this.visitedObjects.put(entity, new NodeBuilderHorizonPair(nodeBuilder, horizon));
+        this.visitedObjects.put(getIdentity(entity), new NodeBuilderHorizonPair(nodeBuilder, horizon));
     }
 
     public void registerRelationship(Mappable mappedRelationship) {
@@ -76,7 +88,7 @@ public boolean removeRegisteredRelationship(Mappable mappedRelationship) {
 
     @Override
     public NodeBuilder visitedNode(Object entity) {
-        NodeBuilderHorizonPair pair = this.visitedObjects.get(entity);
+        NodeBuilderHorizonPair pair = this.visitedObjects.get(getIdentity(entity));
         return pair != null ? pair.getNodeBuilder() : null;
     }
 

core/src/main/java/org/neo4j/ogm/cypher/compiler/MultiStatementCypherCompiler.java

@@ -50,6 +50,7 @@
  *
  * @author Luanne Misquitta
  * @author Mark Angrish
+ * @author Michael J. Simons
  */
 public class MultiStatementCypherCompiler implements Compiler {
 
@@ -62,8 +63,8 @@ public class MultiStatementCypherCompiler implements Compiler {
     private final List<RelationshipBuilder> deletedRelationshipEntityBuilders;
     private StatementFactory statementFactory;
 
-    public MultiStatementCypherCompiler() {
-        this.context = new CypherContext(this);
+    public MultiStatementCypherCompiler(Function<Object, Long> nativeIdProvider) {
+        this.context = new CypherContext(this, nativeIdProvider);
         this.newNodeBuilders = new ArrayList<>();
         this.newRelationshipBuilders = new ArrayList<>();
         this.existingNodeBuilders = new ArrayList<>();

test/src/test/java/org/neo4j/ogm/domain/gh640/MyNode.java

@@ -0,0 +1,115 @@
+/*
+ * Copyright (c) 2002-2019 "Neo4j,"
+ * Neo4j Sweden AB [http://neo4j.com]
+ *
+ * This file is part of Neo4j.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.neo4j.ogm.domain.gh640;
+
+import static org.neo4j.ogm.annotation.Relationship.*;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+
+import org.neo4j.ogm.annotation.GeneratedValue;
+import org.neo4j.ogm.annotation.Id;
+import org.neo4j.ogm.annotation.NodeEntity;
+import org.neo4j.ogm.annotation.Relationship;
+
+/**
+ * @author Michael J. Simons
+ */
+@NodeEntity
+public class MyNode {
+
+    @Id
+    @GeneratedValue
+    private Long id;
+
+    private String name;
+
+    @Relationship(type = "REL_ONE", direction = INCOMING)
+    private MyNode refOne;
+
+    @Relationship(type = "REL_TWO", direction = UNDIRECTED)
+    private List<MyNode> refTwo = new ArrayList<>();
+
+    public MyNode(String name) {
+        this.name = name;
+    }
+
+    public MyNode() {
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public MyNode getRefOne() {
+        return refOne;
+    }
+
+    public void setRefOne(MyNode refOne) {
+        this.refOne = refOne;
+    }
+
+    public List<MyNode> getRefTwo() {
+        return refTwo;
+    }
+
+    public void setRefTwo(List<MyNode> refTwo) {
+        this.refTwo = refTwo;
+    }
+
+    public MyNode copy() {
+        MyNode n = new MyNode();
+        n.id = id;
+        n.name = name;
+        n.setRefOne(refOne);
+        n.setRefTwo(refTwo);
+        return n;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o)
+            return true;
+        if (o == null || getClass() != o.getClass())
+            return false;
+        MyNode myNode = (MyNode) o;
+        return Objects.equals(id, myNode.id);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(id);
+    }
+
+    @Override public String toString() {
+        return "MyNode{" +
+            "id=" + id +
+            ", name='" + name + '\'' +
+            '}';
+    }
+}

test/src/test/java/org/neo4j/ogm/domain/gh640/MyNodeWithAssignedId.java

@@ -0,0 +1,102 @@
+/*
+ * Copyright (c) 2002-2019 "Neo4j,"
+ * Neo4j Sweden AB [http://neo4j.com]
+ *
+ * This file is part of Neo4j.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.neo4j.ogm.domain.gh640;
+
+import static org.neo4j.ogm.annotation.Relationship.*;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+
+import org.neo4j.ogm.annotation.GeneratedValue;
+import org.neo4j.ogm.annotation.Id;
+import org.neo4j.ogm.annotation.NodeEntity;
+import org.neo4j.ogm.annotation.Relationship;
+
+/**
+ * @author Michael J. Simons
+ */
+@NodeEntity
+public class MyNodeWithAssignedId {
+
+    @Id
+    private String name;
+
+    @Relationship(type = "REL_ONE", direction = INCOMING)
+    private MyNodeWithAssignedId refOne;
+
+    @Relationship(type = "REL_TWO", direction = UNDIRECTED)
+    private List<MyNodeWithAssignedId> refTwo = new ArrayList<>();
+
+    public MyNodeWithAssignedId(String name) {
+        this.name = name;
+    }
+
+    public MyNodeWithAssignedId() {
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public MyNodeWithAssignedId getRefOne() {
+        return refOne;
+    }
+
+    public void setRefOne(MyNodeWithAssignedId refOne) {
+        this.refOne = refOne;
+    }
+
+    public List<MyNodeWithAssignedId> getRefTwo() {
+        return refTwo;
+    }
+
+    public void setRefTwo(List<MyNodeWithAssignedId> refTwo) {
+        this.refTwo = refTwo;
+    }
+
+    public MyNodeWithAssignedId copy() {
+        MyNodeWithAssignedId n = new MyNodeWithAssignedId();
+        n.name = name;
+        n.setRefOne(refOne);
+        n.setRefTwo(refTwo);
+        return n;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o)
+            return true;
+        if (o == null || getClass() != o.getClass())
+            return false;
+        MyNodeWithAssignedId myNode = (MyNodeWithAssignedId) o;
+        return Objects.equals(name, myNode.name);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(name);
+    }
+
+    @Override public String toString() {
+        return "MyNodeWithAssignedId{" +
+            "name='" + name + '\'' +
+            '}';
+    }
+}