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A graph module for Choco Solver.
There is a newer version: 4.2.2
/*
 * Copyright (c) 1999-2014, Ecole des Mines de Nantes
 * All rights reserved.
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the Ecole des Mines de Nantes nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE REGENTS AND CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package org.chocosolver.graphsolver.variables;

import org.chocosolver.graphsolver.variables.delta.IGraphDelta;
import org.chocosolver.solver.ICause;
import org.chocosolver.solver.Model;
import org.chocosolver.solver.exception.ContradictionException;
import org.chocosolver.util.objects.graphs.UndirectedGraph;
import org.chocosolver.util.objects.setDataStructures.ISet;

public class UndirectedGraphVar extends GraphVar implements IUndirectedGraphVar {

	//////////////////////////////// GRAPH PART /////////////////////////////////////////

    //***********************************************************************************
    // CONSTRUCTORS
    //***********************************************************************************

	/**
	 * Creates a graph variable
	 *
	 * @param name
	 * @param solver
	 * @param LB
	 * @param UB
	 */
	public UndirectedGraphVar(String name, Model solver, UndirectedGraph LB, UndirectedGraph UB) {
		super(name, solver, LB, UB);
	}

    //***********************************************************************************
    // METHODS
    //***********************************************************************************

	@Override
    public boolean removeArc(int x, int y, ICause cause) throws ContradictionException {
        assert cause != null;
        if (LB.edgeExists(x, y)) {
            this.contradiction(cause, "remove mandatory arc");
            return false;
        }
        if (UB.removeEdge(x, y)) {
            if (reactOnModification) {
                delta.add(x, IGraphDelta.AR_tail, cause);
                delta.add(y, IGraphDelta.AR_head, cause);
            }
            GraphEventType e = GraphEventType.REMOVE_ARC;
            notifyPropagators(e, cause);
            return true;
        }
        return false;
    }

	@Override
    public boolean enforceArc(int x, int y, ICause cause) throws ContradictionException {
        assert cause != null;
        enforceNode(x, cause);
        enforceNode(y, cause);
        if (UB.edgeExists(x, y)) {
            if (LB.addEdge(x, y)) {
                if (reactOnModification) {
                    delta.add(x, IGraphDelta.AE_tail, cause);
                    delta.add(y, IGraphDelta.AE_head, cause);
                }
				GraphEventType e = GraphEventType.ADD_ARC;
                notifyPropagators(e, cause);
                return true;
            }
            return false;
        }
        this.contradiction(cause, "enforce arc which is not in the domain");
        return false;
    }

	@Override
	public ISet getMandNeighOf(int idx) {
		return getMandSuccOrNeighOf(idx);
	}

	@Override
	public ISet getPotNeighOf(int idx) {
		return getPotSuccOrNeighOf(idx);
	}

    @Override
    public boolean isDirected() {
        return false;
    }
}