结构型模式：09-组合模式

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透明组合模式的完整结构

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安全组合模式的完整结构

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abstract class Component {
    public abstract void add(Component c); //增加成员

    public abstract void remove(Component c); //删除成员

    public abstract Component getChild(int i); //获取成员

    public abstract void operation(); //业务方法
}
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class Composite extends Component {
    private String name;
    private ArrayList<Component> list = new ArrayList<Component>();

    Composite(String name) {
        this.name = name;
    }

    @Override
    public void add(Component c) {
        list.add(c);
    }

    @Override
    public void remove(Component c) {
        list.remove(c);
    }

    @Override
    public Component getChild(int i) {
        return (Component) list.get(i);
    }

    @Override
    public void operation() {
        //容器构件具体业务方法的实现
        //递归调用成员构件的业务方法
        for (Object obj : list) {
            ((Component) obj).operation();
        }
    }
}
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class Leaf extends Component {
    private String name;

    public Leaf(String name) {
        this.name = name;
    }

    @Override
    public void add(Component c) {
        //异常处理或错误提示
    }

    @Override
    public void remove(Component c) {
        //异常处理或错误提示
    }

    @Override
    public Component getChild(int i) {
        //异常处理或错误提示
        return null;
    }

    @Override
    public void operation() {
        //叶子构件具体业务方法的实现
        System.out.println(name);
    }
}

class Client {
    public static void main(String args[]) {
        //针对抽象构件编程
        Component file1, file2, file3, file4, file5, folder1, folder2, folder3, folder4;
        folder1 = new Composite("Sunny的资料");
        folder2 = new Composite("图像文件");
        folder3 = new Composite("文本文件");
        folder4 = new Composite("视频文件");
        file1 = new Leaf("小龙女.jpg");
        file2 = new Leaf("张无忌.gif");
        file3 = new Leaf("九阴真经.txt");
        file4 = new Leaf("葵花宝典.doc");
        file5 = new Leaf("笑傲江湖.rmvb");
        folder2.add(file1);
        folder2.add(file2);
        folder3.add(file3);
        folder3.add(file4);
        folder4.add(file5);
        folder1.add(folder2);
        folder1.add(folder3);
        folder1.add(folder4);
        //从“Sunny的资料”节点开始进行杀毒操作
        folder1.operation();
    }
}