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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 JBoss Inc
 *
 * 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.solver.move;

import java.util.Collection;
import java.util.Collections;

import org.apache.commons.lang.ObjectUtils;
import org.apache.commons.lang.builder.EqualsBuilder;
import org.apache.commons.lang.builder.HashCodeBuilder;
import org.optaplanner.core.impl.heuristic.move.Move;
import org.optaplanner.core.impl.score.director.ScoreDirector;
import org.optaplanner.examples.nqueens.domain.Queen;
import org.optaplanner.examples.nqueens.domain.Row;

public class RowChangeMove implements Move {

    private Queen queen;
    private Row toRow;

    public RowChangeMove(Queen queen, Row toRow) {
        this.queen = queen;
        this.toRow = toRow;
    }

    public boolean isMoveDoable(ScoreDirector scoreDirector) {
        return !ObjectUtils.equals(queen.getRow(), toRow);
    }

    public Move createUndoMove(ScoreDirector scoreDirector) {
        return new RowChangeMove(queen, queen.getRow());
    }

    public void doMove(ScoreDirector scoreDirector) {
        scoreDirector.beforeVariableChanged(queen, "row"); // before changes are made
        queen.setRow(toRow);
        scoreDirector.afterVariableChanged(queen, "row"); // after changes are made
    }

    public Collection getPlanningEntities() {
        return Collections.singletonList(queen);
    }

    public Collection getPlanningValues() {
        return Collections.singletonList(toRow);
    }

    public boolean equals(Object o) {
        if (this == o) {
            return true;
        } else if (o instanceof RowChangeMove) {
            RowChangeMove other = (RowChangeMove) o;
            return new EqualsBuilder()
                    .append(queen, other.queen)
                    .append(toRow, other.toRow)
                    .isEquals();
        } else {
            return false;
        }
    }

    public int hashCode() {
        return new HashCodeBuilder()
                .append(queen)
                .append(toRow)
                .toHashCode();
    }

    public String toString() {
        return queen + " => " + toRow;
    }

}