设计模式

[DanceSmile]

/**
*  单例模式 
*/	
class Single 
{
	//  类实例
	private static $instance = null;

	// 防止外部实例化
	private function __construct()	{}

	// 防止外部克隆
	private function __clone() {}

	// 内部实例化对象，单例防止多次实例化
	public static function getInstance()
	{
		if( !(static::$instance instanceof self )  )
		{
			static::$instance = new Single();
		}
		return static::$instance;
	}

}


$single1 =  Single::getInstance();
var_dump($single1);

$single2 =  Single::getInstance();
var_dump($single2);

if( $single1  === $single2 ){
	echo "===";
}