Question

我对模式很新，我正在研究装饰模式，我必须编写一个程序。

在线学习，我找到了一个Decorator模式的例子（它是Java伪代码）：

class Solution1
{
    static interface Component 
    { 
        void doStuff(); 
    }

    static class MyComponent implements Component 
    {
        public void doStuff()
        {
            // ...
        }
    }

    static class ComponentDecorator implements Component  // This is the Decorator pattern.
    { 
        private final Component component;

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

        public void doStuff()
        {
            this.component.doStuff();
        }
    }

    static class ComponentDecorator1 extends ComponentDecorator 
    {
        public ComponentDecorator1(Component component) 
        {
            super(component);
        }

        private void doExtraStuff1()
        {
            // ...
        }

        public void doStuff()
        {
            super.doStuff();
            doExtraStuff1();
        }
    }

    static class ComponentDecorator2 extends ComponentDecorator 
    {
        public ComponentDecorator2(Component component) 
        {
            super(component);
        }

        private void doExtraStuff2()
        {
            // ...
        }

        public void doStuff()
        {
            super.doStuff();
            doExtraStuff2();
        }
    }

    public static void main(String[] args)
    {
        MyComponent         c   = new MyComponent();
        ComponentDecorator1 cd1 = new ComponentDecorator1(c);
        ComponentDecorator2 cd2 = new ComponentDecorator2(cd1);

        cd2.doStuff(); // Executes Component.doStuff, ComponentDecorator1.doExtraStuff1, ComponentDecorator2.doExtraStuff2
    }
};

当我分析这个例子时，我意识到在过去我做了一个非常相似的模式但是以不同的方式：

import java.util.*;

class Solution2
{
    static interface Component 
    { 
        void doStuff(); 
    }

    static class MyComponent implements Component 
    {
        public void doStuff()
        {
            // ...
        }
    }

    static class ComponentDecorator implements Component  // This is NOT the Decorator pattern!
    { 
        private final List<Component> components = new ArrayList<Component>();

        public ComponentDecorator() 
        {
        }

        public ComponentDecorator addComponent(Component component)
        {
            this.components.add(component);
            return this;
        }

        public void removeComponent(Component component) // Can Decorator do this?
        {
            // ...
        }

        public void doStuff()
        {
            for(Component c : this.components) c.doStuff();
        }
    }

    static class ComponentDecorator1 implements Component 
    {
        public ComponentDecorator1() 
        {
        }

        private void doExtraStuff1()
        {
            // ...
        }

        public void doStuff()
        {
            doExtraStuff1();
        }
    }

    static class ComponentDecorator2 implements Component 
    {
        public ComponentDecorator2() 
        {
        }

        private void doExtraStuff2()
        {
            // ...
        }

        public void doStuff()
        {
            doExtraStuff2();
        }
    }

    public static void main(String[] args)
    {
        ComponentDecorator cd  = new ComponentDecorator();
        cd.addComponent(new MyComponent());
        cd.addComponent(new ComponentDecorator1());
        cd.addComponent(new ComponentDecorator2());

        cd.doStuff(); // Executes MyComponent.doStuff, ComponentDecorator1.doExtraStuff1, ComponentDecorator2.doExtraStuff2
    }
}

在我看来，第二个例子可以在可以使用Decorator模式的相同情况下使用，但它更灵活（例如，您可以删除或重新排序列表中的组件），所以我的问题：< / p>