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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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package org.optaplanner.examples.tsp.persistence;

import java.io.File;
import java.util.function.Function;
import java.util.stream.Collectors;

import org.optaplanner.examples.common.persistence.AbstractJsonSolutionFileIO;
import org.optaplanner.examples.tsp.domain.TspSolution;
import org.optaplanner.examples.tsp.domain.location.DistanceType;
import org.optaplanner.examples.tsp.domain.location.RoadLocation;

public final class TspSolutionFileIO extends AbstractJsonSolutionFileIO {

    public TspSolutionFileIO() {
        super(TspSolution.class);
    }

    @Override
    public TspSolution read(File inputSolutionFile) {
        TspSolution tspSolution = super.read(inputSolutionFile);

        if (tspSolution.getDistanceType() == DistanceType.ROAD_DISTANCE) {
            deduplicateRoadLocations(tspSolution);
        }

        return tspSolution;
    }

    private void deduplicateRoadLocations(TspSolution tspSolution) {
        var roadLocationList = tspSolution.getLocationList().stream()
                .filter(location -> location instanceof RoadLocation)
                .map(location -> (RoadLocation) location)
                .collect(Collectors.toList());
        var locationsById = roadLocationList.stream()
                .collect(Collectors.toMap(RoadLocation::getId, Function.identity()));
        /*
         * Replace the duplicate RoadLocation instances in the travelDistanceMap by references to instances from
         * the locationList.
         */
        for (RoadLocation roadLocation : roadLocationList) {
            var newTravelDistanceMap = deduplicateMap(roadLocation.getTravelDistanceMap(),
                    locationsById, RoadLocation::getId);
            roadLocation.setTravelDistanceMap(newTravelDistanceMap);
        }
    }

}