通用的方法，来检查字段是否存在

class AlarmController
{    
    const VALID = 1;  //有效
    const INVALID = 0;  //无效
    
     /**
     * @param array $data
     * @return bool
     */
    public function doCheckShareholderApproval( array $data )
    {
        $fields = array( 'initiator', 'role', 'uid' );
        $check = $this->verifyInputParams( $data, $fields );

        if ( $check['status'] == self::INVALID ) {
            $this->error = array(
                'errorCode' => 0,
                'errorMsg' => $check['msg']
            );
            return false;
        }
    }
    
    /**
     * Check whether the field exists, there is a return value, there is no return error information
     * 检查字段是否存在，存在返回数值，不存在返回错误信息
     * @param $data
     * @param $fields
     * @return array
     */
    function verifyInputParams($data, $fields) {
        $error = array('status' => 1);
        $param = array();
        foreach ($fields as $key => $val) {
            if (!isset($data[$val])) {
                $error['status'] = 0;
                $error['msg'] = 'Illegal operation not find ' . $val . ' field';
                return $error;
            }

            $param[$key] = $data[$val];
        }

        $error['data'] = $param;
        return $error;
    }
}