org.optaplanner.examples.coachshuttlegathering.domain.solver.TransportTimeToHubUpdatingVariableListener Maven / Gradle / Ivy

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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 2015 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.coachshuttlegathering.domain.solver;

import java.util.List;
import java.util.Objects;

import org.optaplanner.core.impl.domain.variable.listener.VariableListener;
import org.optaplanner.core.impl.score.director.ScoreDirector;
import org.optaplanner.examples.coachshuttlegathering.domain.Bus;
import org.optaplanner.examples.coachshuttlegathering.domain.BusOrStop;
import org.optaplanner.examples.coachshuttlegathering.domain.BusStop;
import org.optaplanner.examples.coachshuttlegathering.domain.Shuttle;
import org.optaplanner.examples.coachshuttlegathering.domain.StopOrHub;

public class TransportTimeToHubUpdatingVariableListener implements VariableListener {

    @Override
    public void beforeEntityAdded(ScoreDirector scoreDirector, BusOrStop busOrStop) {
        // Do nothing
    }

    @Override
    public void afterEntityAdded(ScoreDirector scoreDirector, BusOrStop busOrStop) {
        if (busOrStop instanceof BusStop) {
            updateTransportTimeToHub(scoreDirector, (BusStop) busOrStop);
        } else if (busOrStop instanceof Shuttle) {
            updateTransportTimeToHubOfShuttle(scoreDirector, (Shuttle) busOrStop);
        }
    }

    @Override
    public void beforeVariableChanged(ScoreDirector scoreDirector, BusOrStop busOrStop) {
        // Do nothing
    }

    @Override
    public void afterVariableChanged(ScoreDirector scoreDirector, BusOrStop busOrStop) {
        if (busOrStop instanceof BusStop) {
            updateTransportTimeToHub(scoreDirector, (BusStop) busOrStop);
        } else if (busOrStop instanceof Shuttle) {
            updateTransportTimeToHubOfShuttle(scoreDirector, (Shuttle) busOrStop);
        }
    }

    @Override
    public void beforeEntityRemoved(ScoreDirector scoreDirector, BusOrStop busOrStop) {
        // Do nothing
    }

    @Override
    public void afterEntityRemoved(ScoreDirector scoreDirector, BusOrStop busOrStop) {
        // Do nothing
    }

    protected void updateTransportTimeToHub(ScoreDirector scoreDirector, BusStop sourceStop) {
        Bus bus = sourceStop.getBus();
        Integer transportTimeToHub;
        if (bus == null) {
            transportTimeToHub = null;
        } else {
            StopOrHub destination = bus.getDestination();
            if (destination instanceof BusStop // Also implies bus is a Shuttle because a Coach destination is a Hub
                    && ((BusStop) destination).getBus() instanceof Shuttle) {
                // A shuttle that follows a shuttle should have only transportTimeToHub null
                transportTimeToHub = null;
            } else {
                StopOrHub next = sourceStop.getNextStop();
                if (next != null) {
                    transportTimeToHub = next.getTransportTimeToHub();
                } else if (destination != null) {
                    transportTimeToHub = destination.getTransportTimeToHub();
                    next = destination;
                } else {
                    transportTimeToHub = null;
                }
                transportTimeToHub = addTransportTime(transportTimeToHub, sourceStop, next);
            }
        }
        updateTransportTime(scoreDirector, sourceStop, bus, transportTimeToHub);
    }

    private void updateTransportTime(ScoreDirector scoreDirector, BusStop sourceStop, Bus bus, Integer transportTimeToHub) {
        if (sourceStop == null) {
            throw new IllegalArgumentException("The sourceStop (" + sourceStop + ") cannot be null.");
        }
        if (Objects.equals(sourceStop.getTransportTimeToHub(), transportTimeToHub)) {
            return;
        }
        scoreDirector.beforeVariableChanged(sourceStop, "transportTimeToHub");
        sourceStop.setTransportTimeToHub(transportTimeToHub);
        scoreDirector.afterVariableChanged(sourceStop, "transportTimeToHub");
        updateTransportTimeForTransferShuttleList(scoreDirector, sourceStop, bus);
        BusStop toStop = sourceStop;
        for (BusOrStop busOrStop = sourceStop.getPreviousBusOrStop(); busOrStop instanceof BusStop;) {
            BusStop stop = (BusStop) busOrStop;
            transportTimeToHub = addTransportTime(transportTimeToHub, stop, toStop);
            scoreDirector.beforeVariableChanged(stop, "transportTimeToHub");
            stop.setTransportTimeToHub(transportTimeToHub);
            scoreDirector.afterVariableChanged(stop, "transportTimeToHub");
            updateTransportTimeForTransferShuttleList(scoreDirector, stop, bus);
            toStop = stop;
            busOrStop = stop.getPreviousBusOrStop();
        }
    }

    private void updateTransportTimeForTransferShuttleList(ScoreDirector scoreDirector, BusStop parentStop,
            Bus parentBus) {
        List transferShuttleList = parentStop.getTransferShuttleList();
        if (transferShuttleList.isEmpty()) {
            return;
        }
        Integer parentTransportTimeToHub = parentStop.getTransportTimeToHub();
        if (parentBus instanceof Shuttle) {
            // Avoid stack overflow if 2 shuttles bite each others tail or if 1 shuttle bites its own tail
            parentTransportTimeToHub = null;
        }
        for (Shuttle shuttle : transferShuttleList) {
            updateTransportTimeToHubOfShuttle(scoreDirector, parentStop, parentTransportTimeToHub, shuttle);
        }
    }

    private void updateTransportTimeToHubOfShuttle(ScoreDirector scoreDirector, Shuttle shuttle) {
        StopOrHub destination = shuttle.getDestination();
        Integer destinationTransportTimeToHub;
        if (destination != null) {
            if (destination instanceof BusStop
                    && ((BusStop) destination).getBus() instanceof Shuttle) {
                // A shuttle that follows a shuttle should have only transportTimeToHub null
                destinationTransportTimeToHub = null;
            } else {
                destinationTransportTimeToHub = destination.getTransportTimeToHub();
            }
        } else {
            destinationTransportTimeToHub = null;
        }
        updateTransportTimeToHubOfShuttle(scoreDirector, destination, destinationTransportTimeToHub, shuttle);
    }

    private void updateTransportTimeToHubOfShuttle(ScoreDirector scoreDirector, StopOrHub parentStop,
            Integer parentTransportTimeToHub, Shuttle shuttle) {
        if (shuttle.getNextStop() == null) {
            return;
        }
        BusStop lastStop = null;
        for (BusStop stop = shuttle.getNextStop(); stop != null; stop = stop.getNextStop()) {
            lastStop = stop;
        }
        Integer transportTimeToHub = parentTransportTimeToHub;
        transportTimeToHub = addTransportTime(transportTimeToHub, lastStop, parentStop);
        updateTransportTime(scoreDirector, lastStop, shuttle, transportTimeToHub);
    }

    private static Integer addTransportTime(Integer transportTimeToHub, BusStop fromStop, StopOrHub toStop) {
        if (transportTimeToHub == null) {
            return null;
        }
        return transportTimeToHub + fromStop.getBus().getDurationFromTo(fromStop.getLocation(), toStop.getLocation());
    }

}