享元模式經典例題——五子棋遊戲

共享類的接口：

public abstract class FlyWeight {
	protected int x;
	protected int y;
	public abstract void display(int x,int y);
}

具體的FlyWeight：

public class BlackFlyWeight extends FlyWeight {

	@Override
	public void display(int x, int y) {
		System.out.println("●:("+x+","+y+")");
	}

}

public class WhiteFlyWeight extends FlyWeight {

	@Override
	public void display(int x, int y) {
		System.out.println("○:("+x+","+y+")");
	}
}

享元工廠：

public class FlyWeightFactory {
	private static Hashtable<Integer,FlyWeight> hashtable=new Hashtable<Integer,FlyWeight>();
	public static FlyWeight getFlyWeight(int key) {
		
			if (hashtable.containsKey(key)) {
				return hashtable.get(key);
			} else if(key%2==0){
				WhiteFlyWeight whiteFlyWeight = new WhiteFlyWeight();
				hashtable.put(key, whiteFlyWeight);
				return whiteFlyWeight;
			}else {
				BlackFlyWeight blackFlyWeight=new BlackFlyWeight();
				hashtable.put(key, blackFlyWeight);
				return blackFlyWeight;
			}
		
	}
	
}

測試類：

public class Client {
	public static void main(String[] args) {
		for (int i = 0; i < 10; i++) {
			FlyWeight flyWeight = FlyWeightFactory.getFlyWeight(i);
			flyWeight.display(i, new Random().nextInt(20));
		}
	}

}