组合设计模式

package com.jmj.pattern.combination;

/**
 * 菜单组件，属于抽象根节点
 */
public abstract class MenuComponent {

    //菜单组件的名称
    protected String name;
    //菜单组件的层级
    protected int level;

    //添加子菜单
    public void add(MenuComponent menuComponent) {
        throw new UnsupportedOperationException();
    }

    //移出子菜单
    public void remove(MenuComponent menuComponent){
        throw new UnsupportedOperationException();
    }

    //获取指定的子菜单
    public MenuComponent getChild(int index){
        throw new UnsupportedOperationException();
    }

    //获取菜单或者菜单项的名称
    public String getName(){
        return name;
    }

    //打印菜单名称方法(包含子菜单和子菜单项)
        public abstract void print();

}

 

package com.jmj.pattern.combination;

/**
 * 菜单项类
 */
public class MenuItem extends MenuComponent {

    public MenuItem(String name, int level) {
        this.name = name;
        this.level = level;
    }

    @Override
    public void print() {
        for (int i = 0; i < level; i++) {
            System.out.print("--");
        }
        //打印菜单项名称
        System.out.println(name);
    }
}

package com.jmj.pattern.combination;

import java.util.ArrayList;
import java.util.List;

public class Menu extends  MenuComponent{

   //菜单可以有多个子菜单或者子菜单项
    private List menuComponents =new ArrayList<>();

    public Menu(String name,int level) {
        this.name=name;
        this.level=level;
    }

    @Override
    public void add(MenuComponent menuComponent) {
        menuComponents.add(menuComponent);
    }

    @Override
    public void remove(MenuComponent menuComponent) {
        menuComponents.remove(menuComponent);
    }

    @Override
    public MenuComponent getChild(int index) {
        return menuComponents.get(index);
    }

    @Override
    public void print() {
        for (int i = 0; i < level; i++) {
            System.out.print("--");
        }
        //打印菜单名称
        System.out.println(name+":");

        //打印子菜单或者子菜单项名称
        for (MenuComponent menuComponent : menuComponents) {
            menuComponent.print();
        }

    }


}

package com.jmj.pattern.combination;

public class Client {
    public static void main(String[] args) {
        MenuComponent menu = new Menu("菜单管理", 2);
        menu.add(new MenuItem("页面访问",3));
        menu.add(new MenuItem("展开菜单",3));
        menu.add(new MenuItem("编辑菜单",3));
        menu.add(new MenuItem("删除访问",3));
        menu.add(new MenuItem("新增访问",3));
        MenuComponent menu1 = new Menu("权限管理", 2);
        menu1.add(new MenuItem("页面访问",3));
        menu1.add(new MenuItem("提交保存",3));

        MenuComponent menu2 = new Menu("角色管理", 2);
        menu2.add(new MenuItem("页面访问",3));
        menu2.add(new MenuItem("新增角色",3));
        menu2.add(new MenuItem("修改角色",3));

        //创建一级菜单系统管理
        MenuComponent m = new Menu("系统管理", 1);
        m.add(menu);
        m.add(menu1);
        m.add(menu2);

        //打印菜单名称
        m.print();
    }
}