装饰模式可以将职责和使用相分离.
对于人穿衣服而言,其实人是不应该继承Finery的,但是装饰模式需要这样的封装和继承.书中的例子就违背了”细节依赖于抽象”,这里明显的是抽象依赖了细节,把两个完全独立的对象弄成了继承的关系.气人不.
装饰模式其实是抽象出了一系列同类对象,然后让这些对象互相之间都能装饰.主要是体现在两个方法上: decorate() 和 show() , 又把shou()提高为最高接口,让两种不同的类(Person 和 服饰)进行关联,(Person类是没有decorate方法的).
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| package decorator;
public abstract class Finery {
public abstract void show();
}
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| package decorator;
public class Tshirt extends Decorator {
public void show() {
super.show();
System.out.println("wear T shirt");
}
}
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| package decorator;
public class Pans extends Decorator {
public void show() {
super.show();
System.out.println("wear pans");
}
}
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| package decorator;
public class Person extends Finery {
private String name;
public Person(String name){
this.name = name;
}
public void show() {
System.out.println(name + " dress:");
}
}
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| package decorator;
public class Decorator extends Finery {
private Finery component;
public void decorate(Finery component) {
this.component = component;
}
public void show() {
if (component != null) {
component.show();
}
}
}
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| package decorator;
public class Main {
public static void main(String[] args) {
Person person = new Person("小明");
Decorator d1 = new Pans();
Decorator d2 = new Tshirt();
d1.decorate(person);
d2.decorate(d1);
d2.show();
}
}
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