/*
* Copyright 2010 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.api.solver.event;
import java.util.EventListener;
import org.optaplanner.core.api.domain.solution.PlanningSolution;
import org.optaplanner.core.api.score.Score;
import org.optaplanner.core.api.solver.Solver;
import org.optaplanner.core.impl.solver.ProblemFactChange;
/**
* @param <Solution_> the solution type, the class with the {@link PlanningSolution} annotation
*/
public interface SolverEventListener<Solution_> extends EventListener {
/**
* Called once every time when a better {@link PlanningSolution} is found.
* The {@link PlanningSolution} is guaranteed to be initialized.
* Early in the solving process it's usually called more frequently than later on.
* <p>
* Called from the solver thread.
* <b>Should return fast, because it steals time from the {@link Solver}.</b>
* <p>
* In real-time planning
* If {@link Solver#addProblemFactChange(ProblemFactChange)} has been called once or more,
* all {@link ProblemFactChange}s in the queue will be processed and this method is called only once.
* In that case, the former best {@link PlanningSolution} is considered stale,
* so it doesn't matter whether the new {@link Score} is better than that or not.
* @param event never null
*/
void bestSolutionChanged(BestSolutionChangedEvent<Solution_> event);
}