protected function createFilterQuery(Query $query)
{
if ($this->expression === NULL) {
return NULL;
}
$this->expression = $this->doInverse($this->expression);
if (($queryString = $this->expression->build()) !== NULL) {
$key = $this->key ?: md5($queryString);
$fq = $query->createFilterQuery($key)->setQuery($queryString);
if ($this->expression instanceof FieldExpression) {
$fq->addTag($this->expression->getField());
}
if ($this->key !== NULL) {
$fq->addTag($this->key);
}
} else {
$fq = NULL;
}
$this->expression = $this->doInverse($this->expression);
//return to original state
return $fq;
}
