groupMultipleExposedInput example

  public function _build($key) {
    $handlers = &$this->$key;
    foreach ($handlers as $id => $data) {

      if (!empty($handlers[$id]) && is_object($handlers[$id])) {
        $multiple_exposed_input = [0 => NULL];
        if ($handlers[$id]->multipleExposedInput()) {
          $multiple_exposed_input = $handlers[$id]->groupMultipleExposedInput($this->exposed_data);
        }
        foreach ($multiple_exposed_input as $group_id) {
          // Give this handler access to the exposed filter input.           if (!empty($this->exposed_data)) {
            if ($handlers[$id]->isAGroup()) {
              $converted = $handlers[$id]->convertExposedInput($this->exposed_data, $group_id);
              $handlers[$id]->storeGroupInput($this->exposed_data, $converted);
              if (!$converted) {
                continue;
              }
            }