装饰器模式

Component：抽象组件角色，定义一组抽象的接口，规定这个被装饰组件都有哪些功能

ConcreteComponent：实现这个抽象组件的所有功能

Decorator：装饰器角色，它持有一个Component对象实例的引用，定义一个与抽象组件一致的接口

ConcreteDecorate：具体装饰器实现者，负责实现装饰器角色定义的功能

Component

package design.pattern.decorator;

public interface Component {
    public void run();
}

Decorator

package design.pattern.decorator;

public class Decorator implements Component{
    private Component component;
    public Decorator(Component component) {
        this.component = component;
    }
    @Override
    public void run() {
        System.out.println("Decorator do sth...");
        component.run();
    }
}

ConcreteComponent

package design.pattern.decorator;

public class ConcreteComponent implements Component{

    @Override
    public void run() {
        System.out.println("ConcreteComponent Run");
    }

}

Client

package design.pattern.decorator;

public class Client {
    public static void main(String[] args) {
        new Decorator(new ConcreteComponent()).run();
    }
}