/*
* Copyright 2014 Red Hat, Inc. and/or its affiliates.
*
* 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.
*/
package org.optaplanner.core.impl.domain.variable.inverserelation;
import org.optaplanner.core.impl.domain.variable.supply.Supply;
import org.optaplanner.core.impl.score.director.InnerScoreDirector;
/**
* Currently only supported for chained variables,
* which guarantee that no 2 entities use the same planningValue.
* <p>
* To get an instance, demand a {@link SingletonInverseVariableDemand} from {@link InnerScoreDirector#getSupplyManager()}.
*/
public interface SingletonInverseVariableSupply extends Supply {
/**
* If entity1.varA = x then the inverse of x is entity1.
* @param planningValue never null
* @return sometimes null, an entity for which the planning variable is the planningValue.
*/
Object getInverseSingleton(Object planningValue);
}