php设计模式七 ---组合模式

// 1.抽象角色
abstract class MenuComponent{
    public $name;
    public abstract function getName();

    public abstract function add( MenuComponent $menu );
    public abstract function remove( MenuComponent $menu );

    public abstract function getChild( $i );
    public abstract function show();
}

// 2 叶子组件
class MenuItem extends MenuComponent{
    public function __construct( $name ){
        $this->name = $name;
    }

    public function getName(){
        return $this->name;
    }

    public function add( MenuComponent $menu ){
        return ;
    }

    public function remove( MenuComponent $menu ){
        return ;
    }

    public function getChild($i){
        return ;
    }

    public function show(){
        echo ‘&nbsp;|-‘.$this->getName()."<br/>";
    }
}

// 3树枝组合
class Menu extends MenuComponent{
    public $menuComponents = [];

    public function __construct( $name ){
        $this->name = $name;
    }

    public function getName(){
        return $this->name;
    }

    public function add( MenuComponent $menu ){
        if (in_array($menu, $this->menuComponents,true)){
            return ;
        }
        $this->menuComponents[] = $menu;
    }

    public function remove( MenuComponent $menu ){
        if($key = array_search($menu, $this->menuComponents)){
            unset($this->menuComponents[$key]);
        }
    }

    public function getChild($i){
        if( isset($this->menuComponents[$i]) ){
            return $this->menuComponents[$i];
        }
        return ;
    }

    public function show(){
        echo ":".$this->getName()."<br/>";
        foreach($this->menuComponents as $val ){
            $val->show();
        }
    }
}

$menu = new Menu(‘china‘);
$menu->add( new MenuItem(‘shanghai‘));
$menu->add( new MenuItem(‘beijing‘));

$menu->show();