org.graphstream.graph.implementations.SingleNode Maven / Gradle / Ivy

/*
 * This file is part of GraphStream .
 * 
 * GraphStream is a library whose purpose is to handle static or dynamic
 * graph, create them from scratch, file or any source and display them.
 * 
 * This program is free software distributed under the terms of two licenses, the
 * CeCILL-C license that fits European law, and the GNU Lesser General Public
 * License. You can  use, modify and/ or redistribute the software under the terms
 * of the CeCILL-C license as circulated by CEA, CNRS and INRIA at the following
 * URL  or under the terms of the GNU LGPL 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 Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see .
 * 
 * The fact that you are presently reading this means that you have had
 * knowledge of the CeCILL-C and LGPL licenses and that you accept their terms.
 */

/**
 * @since 2009-02-19
 * 
 * @author Guilhelm Savin 
 * @author Yoann Pigné 
 * @author Antoine Dutot 
 * @author Stefan Balev 
 * @author Hicham Brahimi 
 */
package org.graphstream.graph.implementations;

import java.util.HashMap;

import org.graphstream.graph.Edge;
import org.graphstream.graph.Node;

/**
 * Nodes used with {@link SingleGraph}
 *
 */

public class SingleNode extends AdjacencyListNode {
	protected static class TwoEdges {
		protected AbstractEdge in, out;
	}

	protected HashMap neighborMap;

	// *** Constructor ***

	protected SingleNode(AbstractGraph graph, String id) {
		super(graph, id);
		neighborMap = new HashMap(4 * INITIAL_EDGE_CAPACITY / 3 + 1);
	}

	// *** Helpers ***

	@SuppressWarnings("unchecked")
	@Override
	protected  T locateEdge(Node opposite, char type) {
		TwoEdges ee = neighborMap.get(opposite);

		if (ee == null)
			return null;

		if (type == IO_EDGE)
			return (T) (ee.in == null ? ee.out : ee.in);

		return (T) (type == I_EDGE ? ee.in : ee.out);
	}

	@Override
	protected void removeEdge(int i) {
		AbstractNode opposite = (AbstractNode) edges[i].getOpposite(this);
		TwoEdges ee = neighborMap.get(opposite);
		char type = edgeType(edges[i]);
		if (type != O_EDGE)
			ee.in = null;
		if (type != I_EDGE)
			ee.out = null;
		if (ee.in == null && ee.out == null)
			neighborMap.remove(opposite);
		super.removeEdge(i);
	}

	// *** Callbacks ***

	@Override
	protected boolean addEdgeCallback(AbstractEdge edge) {
		AbstractNode opposite = (AbstractNode) edge.getOpposite(this);
		TwoEdges ee = neighborMap.get(opposite);
		if (ee == null)
			ee = new TwoEdges();
		char type = edgeType(edge);
		if (type != O_EDGE) {
			if (ee.in != null)
				return false;
			ee.in = edge;
		}
		if (type != I_EDGE) {
			if (ee.out != null)
				return false;
			ee.out = edge;
		}
		neighborMap.put(opposite, ee);
		return super.addEdgeCallback(edge);
	}

	@Override
	protected void clearCallback() {
		neighborMap.clear();
		super.clearCallback();
	}
}