public function search($string, $index_name = null)
{
$this->_search_string = $string;
if (null !== $index_name) {
// if index name contains , or ' ', multiple index search
if (strpos($index_name, ' ') || strpos($index_name, ',')) {
if (!isset($this->_config['mapping'])) {
$this->_config['mapping'] = false;
}
}
$this->_index_name = $index_name;
}
$this->_connection->resetFilters();
$this->_connection->resetGroupBy();
return $this;
}