装饰模式（Decorator）-山下的石雕厂

装饰模式：是对一个类进行各种功能的丰富，使用Decorator模式扩充类的功能会比用子类生成的方式更加的灵活。

装饰者与被装饰者拥有共同的超类。

类图：

         

 我家有座山，山下有座石雕厂，石雕厂有打磨石狮子的机器

 抽象构建角色（被装饰者）：石雕厂Carved类

 具体构建角色（被装饰者的初始状态）：雕刻石狮子LionCarved

 装饰角色（持有构件的实例）：机器 Machine

 装饰类：CarvedHead CarvedBody  CarvedTail

Carved类

package decorator2;

public abstract class Carved {

	public abstract String toCarved();
	
}

 

LionCarved类

package decorator2;

public class LionCarved extends Carved{

	public String toCarved(){
		return "开始雕刻石狮子";
	}
}

Machine类

package decorator2;

public abstract class Machine extends Carved{

}

CarvedHead类

package decorator2;

public class CarvedHead extends Machine{

	Carved carved;
	
	public CarvedHead(Carved carved){
		this.carved = carved;
	}
	
	public String toCarved(){
		return "先要雕刻头部";
	}
	
}

CarvedBody类

public class CarvedBody extends Machine{

	Carved carved;
	
	public CarvedBody(Carved carved) {
		this.carved = carved;
	}

	public String toCarved(){
		return "然后雕刻身体";
	}
}

CarvedTail类

package decorator2;

public class CarvedTail extends Carved{

	Carved carved;
	
	public CarvedTail(Carved carved){
	   this.carved = carved;	
	}
	
	public String toCarved(){
		return "最后雕刻尾巴";
	}
}

测试Test类

package decorator2;

public class Test {

	public static void main(String args[]){
	   Carved carved = new LionCarved();
	   System.out.println(carved.toCarved());
	   CarvedHead carvedHead = new CarvedHead(carved);
	   System.out.println(carvedHead.toCarved());
	   CarvedBody carvedBody = new CarvedBody(carved);
	   System.out.println(carvedBody.toCarved());
	   CarvedTail carvedTail = new CarvedTail(carved);
	   System.out.println(carvedTail.toCarved());
	}
}

运行结果如下：