2010年上半年

interface FlyBehavior {
    public void fly();
}

class SubSonicFly implements FlyBehavior {
    public void fly() { System.out.println("亚音速飞行！"); }
}

class SuperSonicFly implements FlyBehavior {
    public void fly() { System.out.println("超音速飞行！"); }
}

interface TakeOffBehavior {
    public void takeOff();
}

class VerticalTakeOff implements TakeOffBehavior {
    public void takeOff () { System.out.println("垂直起飞！"); }
}

class LongDistanceTakeOff implements TakeOffBehavior {
    public void takeOff() { System.out.println("长距离起飞！"); }
}

abstract class AirCraft {
    protected FlyBehavior flyBehavior;         // (1)
    protected TakeOffBehavior takeOffBehavior; // (2)

    public void fly() {
        flyBehavior.fly();                     // (3)
    }

    public void takeOff() {
        takeOffBehavior.takeOff();             // (4)
    }
}

class Helicopter extends AirCraft {            // (5)
    public Helicopter () {
        flyBehavior = new SubSonicFly();       // (6)
        takeOffBehavior = new VerticalTakeOff(); // (7)
    }
}