装饰器模式

装饰器模式允许向一个现有的对象添加新的功能，同时又不改变原始结构。装饰类是现有类的一个包装。

基础接口：

public interface Component {

    void operation();
}

原始类：

public class ConcreComponent implements Component {

    @Override
    public void operation() {
        System.out.println("concre component");
    }
}

抽象装饰器：

public abstract class BaseDecorator implements Component {

    public Component component;

    public BaseDecorator(Component component) {
        this.component = component;
    }

    @Override
    public void operation() {
        this.component.operation();
    }
}

自定义装饰器：

public class ConcreDecorator extends BaseDecorator {

    public ConcreDecorator(Component component) {
        super(component);
    }

    @Override
    public void operation() {
        this.component.operation();
        decorateMethod();
    }

    public void decorateMethod() {
        System.out.println("decorateMethod");
    }
}

测试方法：

public class Main {

    public static void main(String[] args) {
        Component concreComponent = new ConcreComponent();
        ConcreDecorator concreDecorator = new ConcreDecorator(concreComponent);
        concreDecorator.operation();
    }
}