protected function createConstraint(Query $query, $queueName)
{
$constraints = array();
$constraints[] = $query->equals('queueName', $queueName);
$constraints[] = $query->equals('state', Message::STATE_PUBLISHED);
$constraints[] = $query->logicalOr($query->equals('starttime', 0), $query->lessThanOrEqual('starttime', time()));
$query->matching($query->logicalAnd($constraints));
}
