/**
* Copyright (c) 2002-2011 "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.graphalgo.impl.util;
import java.util.Iterator;
import org.neo4j.graphalgo.CostEvaluator;
import org.neo4j.graphalgo.WeightedPath;
import org.neo4j.graphdb.Path;
import org.neo4j.helpers.collection.PrefetchingIterator;
public class StopAfterWeightIterator extends PrefetchingIterator<WeightedPath>
{
private final Iterator<Path> paths;
private final CostEvaluator<Double> costEvaluator;
private Double foundWeight;
public StopAfterWeightIterator( Iterator<Path> paths,
CostEvaluator<Double> costEvaluator )
{
this.paths = paths;
this.costEvaluator = costEvaluator;
}
@Override
protected WeightedPath fetchNextOrNull()
{
if ( !paths.hasNext() )
{
return null;
}
WeightedPath path = new WeightedPathImpl( costEvaluator, paths.next() );
if ( foundWeight != null && path.weight() > foundWeight )
{
return null;
}
foundWeight = path.weight();
return path;
}
}