Java设计模式菜鸟系列(一)策略模式建模与实现

[java]代码库

/**
 * 武器 --模板
 */
interface WeaponBehavior {
	void useWeapon();
}

class KnifeBehavior implements WeaponBehavior {
	@Override
	public void useWeapon() {
		System.out.println("实现用匕首刺杀...");
	}
}

class BowAndArrowBehavior implements WeaponBehavior {
	@Override
	public void useWeapon() {
		System.out.println("实现用弓箭设计...");
	}
}

class AxeBehavior implements WeaponBehavior {
	@Override
	public void useWeapon() {
		System.out.println("实现用斧头劈砍...");
	}
}

class SwordBehavior implements WeaponBehavior {
	@Override
	public void useWeapon() {
		System.out.println("实现用宝剑挥舞...");
	}
}

/**
 * 角色
 */
abstract class Character {
	// 将接口作为抽象角色的Field以便封装
	protected WeaponBehavior weaponBehavior;

	public void setWeapon(WeaponBehavior w) {
		weaponBehavior = w;
	}

	/**
	 * 这里有点类似“代理模式”
	 */
	public void performWeapon() {
		// do something...
		weaponBehavior.useWeapon();
		// do something...
	}

	public abstract void fight();
}

/**
 * 国王使用宝剑挥舞
 */
class King extends Character {

	public King() {
		weaponBehavior = new SwordBehavior();
	}

	@Override
	public void fight() {
		System.out.println("国王使用宝剑挥舞...");
	}

}

/**
 * 皇后使用匕首刺杀
 */
class Queen extends Character {

	public Queen() {
		weaponBehavior = new KnifeBehavior();
	}

	@Override
	public void fight() {
		System.out.println("皇后使用匕首刺杀...");
	}

}

/**
 * Knight和Troll以此类推，这里就不写了
 */

/**
 * 客户端测试
 * 
 * @author Leo
 */
public class Test {
	public static void main(String[] args) {
		Character king = new King();
		king.performWeapon();
		// 这里有点类似于“状态模式”
		king.setWeapon(new AxeBehavior());
		king.performWeapon();

		Character queen = new Queen();
		queen.performWeapon();
		queen.setWeapon(new BowAndArrowBehavior());
		queen.performWeapon();
	}
}//源代码片段来自云代码http://yuncode.net