ArrayAccess 创建一个类数组对象

/**

 * 单例模式实现类-->ArrayAccess（数组式访问）接口

 *

 * @author flyer0126

 * @since 2012/4/27

 */

class Single{

private $name;

private static $_Instance = null;

private function __construct()

{

}

static function load()

{

if(null == self::$_Instance)

{

self::$_Instance = new Single();

}

return self::$_Instance;

}

public function setName($name)

{

$this->name = $name;

}

public function getName()

{

return $this->name;

}

}

$s = Single::load();

$s->setName("jack");

echo $s->getName(); //jack

// 调整一下（继承ArrayAccess && 实现4个方法）

class Single implements ArrayAccess

{

private $name;

private static $_Instance = null;

private function __construct()

{

}

static function load()

{

if(null == self::$_Instance)

{

self::$_Instance = new Single();

}

return self::$_Instance;

}

public function setName($name)

{

$this->name = $name;

}

public function getName()

{

return $this->name;

}

/**

       * 实现四个方法

       * offsetExists()，用于标识一个元素是否已定义

       * offsetGet()，用于返回一个元素的值

       * offsetSet()，用于为一个元素设置新值

       * offsetUnset()，用于删除一个元素和相应的值

      **/

public function offsetSet($offset, $value) 

{

if (is_null($offset)) 

{

$this->container[] = $value;

} 

else 

{

$this->container[$offset] = $value;

}

}

public function offsetGet($offset) 

{

return isset($this->container[$offset]) ? $this->container[$offset] : null;

}

public function offsetExists($offset) 

{

return isset($this->container[$offset]);

}

public function offsetUnset($offset) 

{

unset($this->container[$offset]);

}

}

$s = Single::load();

$s->setName("jack");

$s["name"] = "mike";

echo $s->getName(); //jack

echo $s["name"]; //mike

print_r($s);

/**

Single Object

(

    [name:Single:private] => jack

    [container] => Array

        (

            [name] => mike

        )

)

**/