ArrayAccess 建立一個類數組對象

/**

* 單例模式實作類別-->ArrayAccess（數組式訪問）介面

*

* @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

// 調整一下（繼承ArrayAccess && 實現4個方法）

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;

}

/**

* 實現四個方法

* offsetExists()，用於標識一個元素是否已定義

* offsetGet()，用於返回一個元素的值

* offsetSet()，用於為一個元素設定新值

* offsetUnset()，用於刪除一個元素和相應的值

**/

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

)

)

**/

