Vehicle.java

/*
 * 練習問題2.15 p.58
 * 乗り物の現在のスピードを引数で渡された値に変更するchangeSpeedメソッドと、スピードをゼロにするstopメソッドを追加しなさい。
 */

package ch02.ex02_15;

public class Vehicle
{
    private double currentSpeed;
    private double currentDirection;
    private String owner;

    private static int nextID = 1;
    final int id = nextID++;

    public String getOwner()
    {
        return owner;
    }

    public double getCurrentSpeed()
    {
        return currentSpeed;
    }

    public void changeSpeed(double speed)
    {
        currentSpeed = speed;
    }

    public void stop()
    {
        currentSpeed = 0.0;
    }

    public double getCurrentDirection()
    {
        return currentDirection;
    }

    public void setCurrentDirection(double direction)
    {
        currentDirection = direction;
    }

    public Vehicle()
    {
        ;
    }

    public Vehicle(String ownerName)
    {
        owner = ownerName;
    }

    public String toString()
    {
        String desc = "owner: " + owner;

        return desc;
    }

    public static int showCurrentID()
    {
        // まだ識別番号が一度も使われていない場合は0を返す
        return nextID - 1;
    }

    /**
     * @param args
     */
    public static void main(String[] args)
    {

        Vehicle testVehicle1 = new Vehicle("Bob");
        testVehicle1.changeSpeed(3.5);
        System.out.println("Current speed: " + testVehicle1.getCurrentSpeed());

        System.out.println("");

        testVehicle1.changeSpeed(2.1);
        System.out.println("Current speed: " + testVehicle1.getCurrentSpeed());

        System.out.println("");

        testVehicle1.stop();
        System.out.println("after stop method, Current speed: "
                + testVehicle1.getCurrentSpeed());

    }

}