public function init()
	{
		$this->_cache=Yii::app()->getComponent($this->cacheID);
		if(!($this->_cache instanceof ICache))
			throw new CException(Yii::t('yii','CCacheHttpSession.cacheID is invalid. Please make sure "{id}" refers to a valid cache application component.',
				array('{id}'=>$this->cacheID)));
		parent::init();
	}