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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 2020 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.tsp.optional.score;

import org.optaplanner.core.api.score.buildin.simplelong.SimpleLongScore;
import org.optaplanner.core.api.score.stream.Constraint;
import org.optaplanner.core.api.score.stream.ConstraintFactory;
import org.optaplanner.core.api.score.stream.ConstraintProvider;
import org.optaplanner.core.api.score.stream.Joiners;
import org.optaplanner.examples.tsp.domain.Domicile;
import org.optaplanner.examples.tsp.domain.Visit;

public final class TspConstraintProvider implements ConstraintProvider {

    @Override
    public Constraint[] defineConstraints(ConstraintFactory constraintFactory) {
        return new Constraint[] {
                distanceToPreviousStandstill(constraintFactory),
                distanceFromLastVisitToDomicile(constraintFactory)
        };
    }

    private Constraint distanceToPreviousStandstill(ConstraintFactory constraintFactory) {
        return constraintFactory.from(Visit.class)
                .penalizeLong("Distance to previous standstill",
                        SimpleLongScore.ONE,
                        Visit::getDistanceFromPreviousStandstill);
    }

    private Constraint distanceFromLastVisitToDomicile(ConstraintFactory constraintFactory) {
        return constraintFactory.from(Visit.class)
                .ifNotExists(Visit.class, Joiners.equal(visit -> visit, Visit::getPreviousStandstill))
                .join(Domicile.class)
                .penalizeLong("Distance from last visit to domicile",
                        SimpleLongScore.ONE,
                        Visit::getDistanceTo);
    }

}