/**
 * Copyright (c) 2002-2012 "Neo Technology,"
 * Network Engine for Objects in Lund AB [http://neotechnology.com]
 *
 * This file is part of Neo4j.
 *
 * Neo4j is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.neo4j.server.guard;

import org.neo4j.graphdb.GraphDatabaseService;
import org.neo4j.graphdb.Node;
import org.neo4j.graphdb.Relationship;
import org.neo4j.kernel.AbstractGraphDatabase;
import org.neo4j.server.database.GraphDatabaseFactory;
import org.neo4j.tooling.wrap.WrappedGraphDatabase;
import org.neo4j.tooling.wrap.WrappedNode;
import org.neo4j.tooling.wrap.WrappedRelationship;

import java.util.Map;

public class GuardedDatabaseFactory implements GraphDatabaseFactory {

    private final GraphDatabaseFactory dbFactory;
    private final Guard guard;

    public GuardedDatabaseFactory(GraphDatabaseFactory dbFactory, final Guard guard) {
        this.dbFactory = dbFactory;
        this.guard = guard;
    }

    @Override
    public AbstractGraphDatabase createDatabase(String databaseStoreDirectory, Map<String, String> databaseProperties) {
        final GraphDatabaseService db = dbFactory.createDatabase(databaseStoreDirectory, databaseProperties);

        return new WrappedGraphDatabase(db) {
            // private int cnt = 0;

            @Override protected WrappedNode<WrappedGraphDatabase> node(final Node node, boolean created) {
                // if (cnt++ % 1000 == 0)
                guard.check();
                return new WrappedNode<WrappedGraphDatabase>(this) {
                    @Override protected Node actual() {
                        return node;
                    }
                };
            }

            @Override
            protected WrappedRelationship<WrappedGraphDatabase> relationship(final Relationship relationship, boolean created) {
                // if (cnt++ % 1000 == 0)
                guard.check();
                return new WrappedRelationship<WrappedGraphDatabase>(this) {
                    @Override protected Relationship actual() {
                        return relationship;
                    }
                };
            }
        };
    }
}

@@ -2024,32 +2024,119 @@
  guard.check();%0A
+                if (node == null) %7B%0A                    return null;%0A                %7D%0A
                 
@@ -2553,32 +2553,127 @@
  guard.check();%0A
+                if (relationship == null) %7B%0A                    return null;%0A                %7D%0A
                 

fix wrapping null-nodes / relationships that may occur on putIfAbsent