组合模式

/**
* combination模式
*
* 将对象组合成树形结构以表示"部分-整体"的层次结构,使得客户对单个对象
和复合对象的使用具有一致性
*/
    abstract class MenuComponent
    {
        public function add($component){}
        public function remove($component){}
        public function getName(){}
        public function getUrl(){}
        public function display(){}
    }

    class Menu extends MenuComponent
    {
        private $_items = array();
        private $_name = null;
        
        public function __construct($name)
        {
            $this->_name =$name;
        }
        
        public function add($component)
        {
            $this->_items[] =$component;
        }
        
        public function remove($component)
        {
            $key = array_search($component,$this->_items);
            if ($key!==false) {
                unset($this->_items[$key]);
            }
        }
        
        public function display()
        {
            echo "-- ".$this->_name . " ---------<br/>";
            foreach ($this->_items as $item) {
                $item->display();
            }
        }
    }
    
    class Item extends MenuComponent
    {
        private $_name = null;
        private $_url = null;
        
        public function __construct($name,$url)
        {
            $this->_name =$name;
            $this->_url =$url;
        }
        
        public function display()
        {
            echo $this->_name . "#" . $this->_url . "<br/>";
        }
    }
    
    class Client
    {
        private $_menu = null;
        
        public function __construct($menu)
        {
            $this->_menu =$menu;
        }
        
        public function setMenu($menu)
        {
            $this->_menu =$menu;
        }
        
        public function displayMenu()
        {
            $this->_menu->display();
        }
    }
    
// 实例一下
// 创建menu
$subMenu1=new Menu("sub menu1");
$subMenu2=new Menu("sub menu2");
$subMenu3=new Menu("sub menu3");

$item1=new Item("163","www.163.com");
$item2=new Item("sina","www.sina.com");
$subMenu1->add($item1);
$subMenu1->add($item2);
$item3=new Item("baidu","www.baidu.com");
$item4=new Item("google","www.google.com");
$subMenu2->add($item3);
$subMenu2->add($item4);

$allMenu=new Menu("All Menu");
$allMenu->add($subMenu1);
$allMenu->add($subMenu2);
$allMenu->add($subMenu3);

$objClient=new Client($allMenu);

$objClient->displayMenu();
$objClient->setMenu($subMenu2);
$objClient->displayMenu();

参考文章 https://wenku.baidu.com/view/b4c78b4702768e9951e738fb.html