org.drools.planner.examples.tsp.domain.City Maven / Gradle / Ivy

/*
 * Copyright 2011 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.drools.planner.examples.tsp.domain;

import com.thoughtworks.xstream.annotations.XStreamAlias;
import org.apache.commons.lang.builder.CompareToBuilder;
import org.drools.planner.examples.common.domain.AbstractPersistable;

@XStreamAlias("City")
public class City extends AbstractPersistable {

    private String name = null;
    private double latitude;
    private double longitude;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public double getLatitude() {
        return latitude;
    }

    public void setLatitude(double latitude) {
        this.latitude = latitude;
    }

    public double getLongitude() {
        return longitude;
    }

    public void setLongitude(double longitude) {
        this.longitude = longitude;
    }

    // ************************************************************************
    // Complex methods
    // ************************************************************************

    /**
     * The distance is not in miles or km, but in the TSPLIB's unit of measurement.
     * @param city never null
     * @return a positive number
     */
    public int getDistance(City city) {
        // Implementation specified by TSPLIB http://www2.iwr.uni-heidelberg.de/groups/comopt/software/TSPLIB95/
        // Euclidean distance (Pythagorean theorem) - not correct when the surface is a sphere
        double latitudeDifference = Math.abs(city.latitude - latitude);
        double longitudeDifference = Math.abs(city.longitude - longitude);
        double distance = Math.sqrt(
                (latitudeDifference * latitudeDifference) + (longitudeDifference * longitudeDifference));
        return (int) (distance + 0.5);
    }

    @Override
    public String toString() {
        if (name == null) {
            return id.toString();
        }
        return id.toString() + "-" + name;
    }

    public String getSafeName() {
        if (name == null) {
            return id.toString();
        }
        return name;
    }

}