UniquenessFilter.java

/**
 * Copyright (c) 2002-2013 "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.graphdb.traversal;

public interface UniquenessFilter
{
    /**
     * The check whether or not to expand the first branch is a separate
     * method because it may contain checks which would be unnecessary for
     * all other checks. So it's purely an optimization.
     * 
     * @param branch the first branch to check, i.e. the branch representing
     * the start node in the traversal.
     * @return whether or not {@code branch} is unique, and hence can be
     * visited in this traversal.
     */
    boolean checkFirst( TraversalBranch branch );
    
    /**
     * Checks whether or not {@code branch} is unique, and hence can be
     * visited in this traversal.
     * @param branch the {@link TraversalBranch} to check for uniqueness.
     * @return whether or not {@code branch} is unique, and hence can be
     * visited in this traversal.
     */
    boolean check( TraversalBranch branch );
}