php指定参数部类

	public function execute(PwThreadDataSource $ds) {<br />
		$this->_ds = $ds;

abstract class PwThreadDataSource {<br />
<br />
	protected $urlArgs = array();<br />
<br />
	/**<br />
	 * 获取帖子统计数<br />
	 *<br />
	 * @return int<br />
	 */<br />
	abstract public function getTotal();<br />
	<br />
	/**<br />
	 * 获取帖子<br />
	 *<br />
	 * @param int $limit 获取条目<br />
	 * @param int $offset 帖子起始偏移量<br />
	 * @return array<br />
	 */<br />
	abstract public function getData($limit, $offset);