Java tutorial
/* * Copyright 2014 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.optaplanner.examples.tsp.domain.location; import com.thoughtworks.xstream.annotations.XStreamAlias; import com.thoughtworks.xstream.annotations.XStreamInclude; import org.apache.commons.lang3.ObjectUtils; import org.optaplanner.examples.common.domain.AbstractPersistable; import org.optaplanner.examples.vehiclerouting.domain.VehicleRoutingSolution; @XStreamAlias("TspLocation") @XStreamInclude({ AirLocation.class, RoadLocation.class }) public abstract class Location extends AbstractPersistable { protected String name = null; protected double latitude; protected double longitude; public Location() { } public Location(long id, double latitude, double longitude) { super(id); this.latitude = latitude; this.longitude = 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's unit of measurement depends on the {@link VehicleRoutingSolution}'s {@link DistanceType}. * It can be in miles or km, but for most cases it's in the TSPLIB's unit of measurement. * @param location never null * @return a positive number, the distance multiplied by 1000 to avoid floating point arithmetic rounding errors */ public abstract long getDistanceTo(Location location); public double getAirDistanceDoubleTo(Location location) { // 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 = location.latitude - latitude; double longitudeDifference = location.longitude - longitude; return Math.sqrt((latitudeDifference * latitudeDifference) + (longitudeDifference * longitudeDifference)); } /** * The angle relative to the direction EAST. * @param location never null * @return in Cartesian coordinates */ public double getAngle(Location location) { // Euclidean distance (Pythagorean theorem) - not correct when the surface is a sphere double latitudeDifference = location.latitude - latitude; double longitudeDifference = location.longitude - longitude; return Math.atan2(latitudeDifference, longitudeDifference); } @Override public String toString() { if (name == null) { return super.toString(); } return name; } }