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OptaPlanner solves planning problems. This lightweight, embeddable planning engine implements powerful and scalable algorithms to optimize business resource scheduling and planning. This module contains the examples which demonstrate how to use it in a normal Java application.
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/*
 * 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.examples.nqueens.app;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;

import org.optaplanner.core.api.solver.Solver;
import org.optaplanner.core.api.solver.SolverFactory;
import org.optaplanner.core.config.constructionheuristic.ConstructionHeuristicPhaseConfig;
import org.optaplanner.core.config.constructionheuristic.ConstructionHeuristicType;
import org.optaplanner.core.config.heuristic.selector.common.SelectionOrder;
import org.optaplanner.core.config.heuristic.selector.move.generic.ChangeMoveSelectorConfig;
import org.optaplanner.core.config.localsearch.LocalSearchPhaseConfig;
import org.optaplanner.core.config.localsearch.decider.acceptor.AcceptorConfig;
import org.optaplanner.core.config.phase.PhaseConfig;
import org.optaplanner.core.config.score.director.ScoreDirectorFactoryConfig;
import org.optaplanner.core.config.solver.SolverConfig;
import org.optaplanner.core.config.solver.termination.TerminationConfig;
import org.optaplanner.examples.common.app.CommonApp;
import org.optaplanner.examples.nqueens.domain.NQueens;
import org.optaplanner.examples.nqueens.domain.Queen;
import org.optaplanner.examples.nqueens.swingui.NQueensPanel;
import org.optaplanner.persistence.common.api.domain.solution.SolutionFileIO;
import org.optaplanner.persistence.xstream.impl.domain.solution.XStreamSolutionFileIO;

/**
 * For an easy example, look at {@link NQueensHelloWorld} instead.
 */
public class NQueensApp extends CommonApp {

    public static final String SOLVER_CONFIG
            = "org/optaplanner/examples/nqueens/solver/nqueensSolverConfig.xml";

    public static final String DATA_DIR_NAME = "nqueens";

    public static void main(String[] args) {
        prepareSwingEnvironment();
        new NQueensApp().init();
    }

    public NQueensApp() {
        super("N queens",
                "Place queens on a chessboard.\n\n" +
                        "No 2 queens must be able to attack each other.",
                SOLVER_CONFIG, DATA_DIR_NAME,
                NQueensPanel.LOGO_PATH);
    }

    @Override
    protected Solver createSolver() {
        return createSolverByXml();
    }

    /**
     * Normal way to create a {@link Solver}.
     * @return never null
     */
    protected Solver createSolverByXml() {
        SolverFactory solverFactory = SolverFactory.createFromXmlResource(SOLVER_CONFIG);
        return solverFactory.buildSolver();
    }

    /**
     * Unused alternative. Abnormal way to create a {@link Solver}.
     * 
     * Not recommended! It is recommended to use {@link #createSolverByXml()} instead.
     * @return never null
     */
    protected Solver createSolverByApi() {
        SolverFactory solverFactory = SolverFactory.createEmpty();
        SolverConfig solverConfig = solverFactory.getSolverConfig();

        solverConfig.setSolutionClass(NQueens.class);
        solverConfig.setEntityClassList(Collections.>singletonList(Queen.class));

        ScoreDirectorFactoryConfig scoreDirectorFactoryConfig = new ScoreDirectorFactoryConfig();
        scoreDirectorFactoryConfig.setScoreDrlList(
                Arrays.asList("org/optaplanner/examples/nqueens/solver/nQueensScoreRules.drl"));
        solverConfig.setScoreDirectorFactoryConfig(scoreDirectorFactoryConfig);

        solverConfig.setTerminationConfig(new TerminationConfig().withBestScoreLimit("0"));
        List phaseConfigList = new ArrayList<>();

        ConstructionHeuristicPhaseConfig constructionHeuristicPhaseConfig = new ConstructionHeuristicPhaseConfig();
        constructionHeuristicPhaseConfig.setConstructionHeuristicType(
                ConstructionHeuristicType.FIRST_FIT_DECREASING);
        phaseConfigList.add(constructionHeuristicPhaseConfig);

        LocalSearchPhaseConfig localSearchPhaseConfig = new LocalSearchPhaseConfig();
        ChangeMoveSelectorConfig changeMoveSelectorConfig = new ChangeMoveSelectorConfig();
        changeMoveSelectorConfig.setSelectionOrder(SelectionOrder.ORIGINAL);
        localSearchPhaseConfig.setMoveSelectorConfig(changeMoveSelectorConfig);
        localSearchPhaseConfig.setAcceptorConfig(new AcceptorConfig().withEntityTabuSize(5));
        phaseConfigList.add(localSearchPhaseConfig);

        solverConfig.setPhaseConfigList(phaseConfigList);
        return solverFactory.buildSolver();
    }

    @Override
    protected NQueensPanel createSolutionPanel() {
        return new NQueensPanel();
    }

    @Override
    public SolutionFileIO createSolutionFileIO() {
        return new XStreamSolutionFileIO<>(NQueens.class);
    }

}