【java设计模式】【结构模式Structural Pattern】装饰模式Decorator Pattern

public class Client {
    public static void main(String[] args) {
        Component component=new ConcreteComponent();
        component=new ConcreteDecoratorA(component);
        component=new ConcreteDecoratorB(component);
        component.doSth();
    }
}
interface Component{
    void doSth();
}
class ConcreteComponent implements Component{
    @Override
    public void doSth() {
        System.out.println("This is ConcreteComponent.doSth()");
    }
}
abstract class Decorator implements Component{}
class ConcreteDecoratorA extends Decorator{
    private Component component;
    public ConcreteDecoratorA(Component component){
        this.component=component;
    }
    @Override
    public void doSth() {
        concreteDecoratorA_method();
        component.doSth();        
    }
    public void concreteDecoratorA_method(){
        System.out.println("This is ConcreteDecoratorA.concreteDecoratorA_method()");
    }
}
class ConcreteDecoratorB extends Decorator{
    private Component component;
    public ConcreteDecoratorB(Component component){
        this.component=component;
    }
    @Override
    public void doSth() {        
        concreteDecoratorB_method();
        component.doSth();
    }
    public void concreteDecoratorB_method(){
        System.out.println("This is ConcreteDecoratorB.concreteDecoratorB_method()");
    }
}