NotEqual.java
- /* Copyright 2015 Laurent COCAULT
- * Licensed to Laurent COCAULT under one or more contributor license agreements.
- * See the NOTICE file distributed with this work for additional information
- * regarding copyright ownership. Laurent COCAULT licenses this file to You
- * 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.
- */
- package org.csp.constraint.model.general;
- import org.csp.constraint.model.BinaryConstraint;
- import org.csp.constraint.model.Variable;
- /**
- * Binary constraint specifying that two variables are different.
- */
- public class NotEqual<T> extends BinaryConstraint<T> {
- /**
- * Constructor for constraint "left != right".
- * @param left
- * Left variable
- * @param right
- * Right variable
- */
- public NotEqual(final Variable<T> left, final Variable<T> right) {
- super(left.getName() + " != " + right.getName(), left, right);
- }
- /**
- * {@inheritDoc}
- */
- @Override
- public void propagate() {
- // The current implementation of the propagation is not as efficient as
- // it could be.
- // TODO Enhancement
- // Get the two variables concerned
- final Variable<T> first = getFirstVariable();
- final Variable<T> second = getSecondVariable();
- // Propagate on the first variable
- if (second.isBound()) {
- if (first.removeValue(second.getValue())) {
- addRecentChangedVariable(first);
- }
- }
- // Propagate on the second variable.
- if (first.isBound()) {
- if (second.removeValue(first.getValue())) {
- addRecentChangedVariable(second);
- }
- }
- }
- }