protected function getCondition(Criterion $criterion)
{
$values = (array) $criterion->value;
$start = $values[0];
$end = isset($values[1]) ? $values[1] : null;
if ($criterion->operator === Operator::LT || $criterion->operator === Operator::LTE) {
$end = $start;
$start = null;
}
$range = $this->getQueryRange($criterion->operator, $start, $end);
return array('query_string' => array('query' => 'fields_doc.' . $criterion->target . ':' . $range));
}