/**
* Pops the newest Filter from each of <tt>queries</tt>,
* grouping each popped Filter into one new FilterGroup.
* Adds that new FilterGroup as the newest Filter in this
* Query.
* <p>
* The FilterGroup's logic will be determined by <tt>op</tt>.
* @param string op operator name
* @param array Array of Query filter criteria
* @return obj queries Query object
*/
protected function popFilters($op, array $queries)
{
$group = new FilterGroup();
$group->op($op);
foreach ($queries as $query) {
if (!$query->rowFilters) {
//check to ensure nly filters are combined
throw new Exception("Operator " . $op . " can be used only to combine row filters");
return false;
} else {
$group->add(array_pop($query->rowFilters));
}
}
$this->add($group);
return $this;
}