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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.solver.move;

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

import org.optaplanner.core.impl.heuristic.move.AbstractMove;
import org.optaplanner.core.impl.score.director.ScoreDirector;
import org.optaplanner.examples.nqueens.domain.NQueens;
import org.optaplanner.examples.nqueens.domain.Queen;
import org.optaplanner.examples.nqueens.domain.Row;

public class RowChangeMove extends AbstractMove {

    private Queen queen;
    private Row toRow;

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

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

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

    @Override
    protected void doMoveOnGenuineVariables(ScoreDirector scoreDirector) {
        scoreDirector.beforeVariableChanged(queen, "row"); // before changes are made
        queen.setRow(toRow);
        scoreDirector.afterVariableChanged(queen, "row"); // after changes are made
    }

    @Override
    public RowChangeMove rebase(ScoreDirector destinationScoreDirector) {
        return new RowChangeMove(destinationScoreDirector.lookUpWorkingObject(queen),
                destinationScoreDirector.lookUpWorkingObject(toRow));
    }

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

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

    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }
        final RowChangeMove other = (RowChangeMove) o;
        return Objects.equals(queen, other.queen) &&
                Objects.equals(toRow, other.toRow);
    }

    @Override
    public int hashCode() {
        return Objects.hash(queen, toRow);
    }

    @Override
    public String toString() {
        return queen + " {" + queen.getRow() + " -> " + toRow + "}";
    }

}