UnaryConstraint.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;
- /**
- * Represents an unary constraint in a constraint solving problem. To define a
- * new unary constraint, inherit this class and define the propagate method.
- */
- public abstract class UnaryConstraint<T> extends Constraint<T> {
- /**
- * An unary constraint is associated with only one variable.
- */
- private Variable<T> variable_;
- /**
- * Constructor of an unary constraint. It references the variable given as
- * parameters.
- * @param name
- * Name of the binary constraint
- * @param variable
- * Reference of the variable
- */
- public UnaryConstraint(final String name, final Variable<T> variable) {
- super(name);
- variable_ = variable;
- }
- /**
- * Get the variable associated with the constraint.
- * @return The reference of the variable associated with the constraint
- */
- public Variable<T> getVariable() {
- return variable_;
- }
- /**
- * {@inheritDoc}
- */
- @Override
- public boolean isBinary() {
- return false;
- }
- /**
- * {@inheritDoc}
- */
- @Override
- public boolean isTernary() {
- return false;
- }
- /**
- * {@inheritDoc}
- */
- @Override
- public boolean isUnary() {
- return true;
- }
- /**
- * {@inheritDoc}
- */
- @Override
- public boolean isUnsized() {
- return false;
- }
- /**
- * {@inheritDoc}
- */
- @Override
- public boolean isVariableReferenced(final Variable<T> variable) {
- return variable_ == variable;
- }
- /**
- * {@inheritDoc}
- */
- @Override
- public boolean revise() {
- try {
- // Propagate and check if the domain is empty
- if (isPropagationEnabled()) {
- propagate();
- }
- return !variable_.getDomain().isEmpty();
- } catch (EmptyDomainException e) {
- // If the domain has been emptied, return false
- return false;
- }
- }
- }