/*
* Encog(tm) Core v3.3 - Java Version
* http://www.heatonresearch.com/encog/
* https://github.com/encog/encog-java-core
* Copyright 2008-2014 Heaton Research, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* For more information on Heaton Research copyrights, licenses
* and trademarks visit:
* http://www.heatonresearch.com/copyright
*/
package org.encog.ml.graph.search;
import java.util.HashSet;
import java.util.Set;
import org.encog.EncogError;
import org.encog.ml.graph.BasicEdge;
import org.encog.ml.graph.BasicGraph;
import org.encog.ml.graph.BasicNode;
import org.encog.ml.graph.BasicPath;
public abstract class AbstractGraphSearch implements GraphSearch {
private final BasicGraph graph;
private final SearchGoal goal;
private final FrontierHolder frontier = new FrontierHolder(this);
private final Set<BasicNode> explored = new HashSet<BasicNode>();
private BasicPath solution;
public AbstractGraphSearch(BasicGraph theGraph, BasicNode startingPoint, SearchGoal theGoal)
{
this.graph = theGraph;
this.goal = theGoal;
frontier.add(new BasicPath(startingPoint));
}
public BasicGraph getGraph() {
return graph;
}
public SearchGoal getGoal() {
return goal;
}
public void iteration() {
if (solution == null) {
if( this.frontier.size()==0 ) {
throw new EncogError("Frontier is empty, cannot find solution.");
}
BasicPath path = this.frontier.pop();
if (this.goal.isGoalMet(path)) {
this.solution = path;
return;
}
BasicNode state = path.getDestinationNode();
this.explored.add(state);
for (BasicEdge connection : state.getConnections()) {
if( !this.explored.contains(connection.getTo()) &&
!this.frontier.containsDestination(connection.getTo())) {
BasicPath path2 = new BasicPath(path, connection.getTo());
this.frontier.add(path2);
}
}
}
}
/**
* @return the solution
*/
public BasicPath getSolution() {
return solution;
}
}