【计算机网络】1.5——计算机网络的体系结构（网络分层模型）

组合模式（Composite Pattern）

提供demo版代码更容易理解

/**
 * @author zhou
 *  组件抽象类
 */
abstract class Component {
    protected String name;

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

    public abstract void operation();

    // 可以选择在组件类中提供默认实现，简化容器类的实现
    public void add(Component component) {
        throw new UnsupportedOperationException();
    }

    public void remove(Component component) {
        throw new UnsupportedOperationException();
    }

    public Component getChild(int index) {
        throw new UnsupportedOperationException();
    }
}

/**
 * @author zhou
 *  容器类
 */
class Composite extends Component {
    private List<Component> children = new ArrayList<>();

    public Composite(String name) {
        super(name);
    }

    @Override
    public void operation() {
        System.out.println("Composite " + name + ": Operation");

        for (Component child : children) {
            child.operation();
        }
    }

    @Override
    public void add(Component component) {
        children.add(component);
    }

    @Override
    public void remove(Component component) {
        children.remove(component);
    }

    @Override
    public Component getChild(int index) {
        return children.get(index);
    }
}

/**
 * @author zhou
 *  叶子类
 */
class Leaf extends Component {
    public Leaf(String name) {
        super(name);
    }

    @Override
    public void operation() {
        System.out.println("Leaf " + name + ": Operation");
    }
}

/**
 * @author zhou
 *  客户端使用
 */
public class Main {
    public static void main(String[] args) {
        // 创建组合对象
        Composite root = new Composite("root");
        Composite branch1 = new Composite("branch1");
        Composite branch2 = new Composite("branch2");

        // 创建叶子对象
        Leaf leaf1 = new Leaf("leaf1");
        Leaf leaf2 = new Leaf("leaf2");
        Leaf leaf3 = new Leaf("leaf3");
        Leaf leaf4 = new Leaf("leaf4");

        // 组合对象添加子节点
        root.add(branch1);
        root.add(branch2);
        branch1.add(leaf1);
        branch1.add(leaf2);
        branch2.add(leaf3);
        branch2.add(leaf4);

        // 调用组合对象的操作
        root.operation();
    }
}