EntireGraphDeletor.java

package org.neo4j.util;

import java.util.Collection;
import java.util.HashSet;

import org.neo4j.graphdb.Node;
import org.neo4j.graphdb.Relationship;

/**
 * Deletes an entire graph, i.e. all connected nodes (and their connected nodes)
 * from a start node (any start node in that graph). It is mostly used in
 * some test cases.
 */
public class EntireGraphDeletor implements GraphDeletor
{
	public void delete( Node startNode )
	{
		removeNodeAndThoseConnectedWith( new HashSet<Node>(),
			new HashSet<Relationship>(), startNode );
	}

	private void removeNodeAndThoseConnectedWith( Collection<Node> deletedNodes,
		Collection<Relationship> deletedRels, Node node )
	{
		for ( Relationship rel : node.getRelationships() )
		{
			Node sub = rel.getOtherNode( node );
			if ( deletedRels.add( rel ) )
			{
				aboutToDeleteRelationship( rel );
				rel.delete();
			}
			removeNodeAndThoseConnectedWith( deletedNodes, deletedRels, sub );
		}
		if ( deletedNodes.add( node ) )
		{
			aboutToDeleteNode( node );
			node.delete();
		}
	}
	
	protected void aboutToDeleteRelationship( Relationship relationship )
	{
	}
	
	protected void aboutToDeleteNode( Node node )
	{
	}
}