PHP设计模式---组合模式(Composite Pattern)

2019-05-20 11:28:12 Albin Wong 1386

### 定义
允许将对象组合成树形结构来表现整体部分的参差结构，组合能让客户以一致的方式处理个别对象以及对象的组合
### 原理
定义一个接口，所有类都继承这个接口（这为客户能一直处理枝叶对象提供了可能，因为每个类都要实现这里的每一个抽象方法）
```php
abstract classc MenuComponent {
	//获得类名称
	public $name;
	//添加类别
	public abstract function getName();
	//删除类别
	public abstract function add(MenuComponent $menu);
	//获得子类别
	public abstract function remove(MenuComponent $menu);
	//显示类别名称
	public abstract function getChild($i);
	public abstract function show();
}
```
 叶子类它内部没有别的类，是最底层的类，继承接口的时候就添加跟删除返回一个假
 树干类它有一个属性用来以数组的形式存储叶子类对象，对应的就应该在添加跟删除中实现添加跟删除叶子类的实现
 这两种类还有3个方法需要实现，分别是getname 用来返回这个类的名字 getchild  获得类的子类  show 如果是树干类就进行遍历如果不是
就不遍历,这个方法有种递归的意思，当数组中的元素还是个树干就在遍历；这样才能显示出树形菜单的效果

### 代码示例
##### 所有树状菜单都继承的接口
```php
abstract class MenuComponent
{
		//获得类名称
		public $name;
		//添加类别
		public abstract function getName();
		//删除类别
		public abstract function add(MenuComponent $menu);
		//获得子类别
		public abstract function remove(MenuComponent $menu);
		//显示类别名称
		public abstract function getChild($i);
		public abstract function show();
}
```
##### 枝叶（最底层类）类
```
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()." ";
	}
}
```
##### 树干（一级类别）类
```php
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 ":" . $this->getName() . " ";
		foreach($this->menuComponents as $v){
		$v->show();
		}
	}
}
```
##### 测试代码
```php
class testDriver
{
	public function run()
	{
		$menu1 = new Menu('文学');//根分类
		$menuitem1 = new MenuItem('绘画');//第一个子类
		$menuitem2 = new MenuItem('书法');//第二个子类
		$menuitem3 = new MenuItem('小说');//第三个子类
		$menuitem4 = new Menu('雕刻');//第四个子类
		$menu1->add($menuitem1);
		$menu1->add($menuitem2);
		$menu1->add($menuitem3);
		$menuitem5=new MenuItem('核雕');//第四个子类的第一个子类
		$menuitem6=new MenuItem('石雕');//第四个子类的第二个子类
		$menuitem4->add($menuitem5);
		$menuitem4->add($menuitem6);
		$menu1->add($menuitem4);
		//$menu1->add($menuitem4);
		$menu1->show();//显示类别
	}
}

//测试代码：
$test = new testDriver();
$test->run();
```

(3) Comments

John Doe- Reply

February 26, 2013 at 1:18 pm
- saqib sarwar- Reply
  
  February 26, 2013 at 1:20 pm
  
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John Doe- Reply

February 26, 2013 at 1:27 pm

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PHP设计模式---组合模式(Composite Pattern)

(3) Comments

John Doe- Reply

saqib sarwar- Reply

John Doe- Reply

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