组合模式有时候又叫做部分-整体模式，它把程序内部简单元素和复杂元素提供给客户端统一的接口，，使客户端和程序的内部结构结构，内部可以随意更改扩展。
从类图上看组合模式形成一种树形结构，由枝干和叶子继承Compont显然不符合里氏代换原则。
组合模式类图：
php代码实例（来自）：
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();}class MenuItem extends MenuComponent{public function __construct($name){$this->name = $name;}public function getName(){return $this->name;}public function add(MenuComponent $menu){return false;}public function remove(MenuComponent $menu){return false;}public function getChild($i){return null;}public function show(){echo " |-".$this->getName()."\n";}}class Menu extends MenuComponent{public $menuComponents = array();public function __construct($name){$this->name = $name;}public function getName(){return $this->name;}public function add(MenuComponent $menu){$this->menuComponents[] = $menu;}public function remove(MenuComponent $menu){$key = array_search($menu, $this->menuComponents);if($key !== false) unset($this->menuComponents[$key]);}public function getChild($i){if(isset($this->menuComponents[$i])) return $this->menuComponents[$i];return null;}public function show(){echo ":" . $this->getName() . "\n";foreach($this->menuComponents as $v){$v->show();}}}class testDriver{ public function run() { $menu1 = new Menu(‘文学’); $menuitem1 = new MenuItem(‘绘画’); $menuitem2 = new MenuItem(‘书法’); $menuitem3 = new MenuItem(‘小说’); $menuitem4 = new MenuItem(‘雕刻’); $menu1->add($menuitem1); $menu1->add($menuitem2); $menu1->add($menuitem3); $menu1->add($menuitem4); $menu1->show(); }}$test = new testDriver();$test->run();
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多看书，看好书。
