/**
* Copyright (c) 2002-2010 "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 Affero 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package org.neo4j.graphdb.traversal;
/**
* Decides "where to go next" in a traversal. It keeps state itself, f.ex. its
* own current position. Examples of implementations are "depth first" and
* "breadth first". This is an interface to implement if you'd like to implement
* f.ex. a "best first" selector based on your own criteria.
*/
public interface BranchSelector
{
/**
* Decides the next position ("where to go from here") from the current
* position, based on the {@code rules}. Since {@link TraversalBranch}
* has the {@link TraversalBranch#node()} of the position and the
* {@link TraversalBranch#relationship()} to how it got there as well as
* {@link TraversalBranch#position()}, decisions
* can be based on the current expansion source and the given rules.
*
* @return the next position based on the current position and the
* {@code rules} of the traversal.
*/
TraversalBranch next();
}