/**
  * read data
  *
  * @access protected
  * @param
  * @return
  */
 public function readSubscriberData()
 {
     include_once './Services/Membership/classes/class.ilParticipants.php';
     $sub_data = ilParticipants::lookupSubscribersData($this->getParentObject()->object->getId());
     $sub_ids = array();
     foreach ($sub_data as $usr_id => $usr_data) {
         $sub_ids[] = $usr_id;
     }
     $this->determineOffsetAndOrder();
     include_once './Services/User/classes/class.ilUserQuery.php';
     $additional_fields = $this->getSelectedColumns();
     unset($additional_fields["firstname"]);
     unset($additional_fields["lastname"]);
     unset($additional_fields["last_login"]);
     unset($additional_fields["access_until"]);
     $udf_ids = $usr_data_fields = $odf_ids = array();
     foreach ($additional_fields as $field) {
         if (substr($field, 0, 3) == 'udf') {
             $udf_ids[] = substr($field, 4);
             continue;
         }
         if (substr($field, 0, 3) == 'odf') {
             $odf_ids[] = substr($field, 4);
             continue;
         }
         $usr_data_fields[] = $field;
     }
     $usr_data = ilUserQuery::getUserListData($this->getOrderField(), $this->getOrderDirection(), $this->getOffset(), $this->getLimit(), '', '', null, false, false, 0, 0, null, $usr_data_fields, $sub_ids);
     foreach ((array) $usr_data['set'] as $user) {
         $usr_ids[] = $user['usr_id'];
     }
     // merge course data
     $course_user_data = $this->getParentObject()->readMemberData($usr_ids, $this->type == 'admin');
     $a_user_data = array();
     foreach ((array) $usr_data['set'] as $ud) {
         $a_user_data[$ud['usr_id']] = array_merge($ud, (array) $course_user_data[$ud['usr_id']]);
     }
     // Custom user data fields
     if ($udf_ids) {
         include_once './Services/User/classes/class.ilUserDefinedData.php';
         $data = ilUserDefinedData::lookupData($usr_ids, $udf_ids);
         foreach ($data as $usr_id => $fields) {
             if (!$this->checkAcceptance($usr_id)) {
                 continue;
             }
             foreach ($fields as $field_id => $value) {
                 $a_user_data[$usr_id]['udf_' . $field_id] = $value;
             }
         }
     }
     // Object specific user data fields
     if ($odf_ids) {
         include_once './Modules/Course/classes/Export/class.ilCourseUserData.php';
         $data = ilCourseUserData::_getValuesByObjId($this->getParentObject()->object->getId());
         foreach ($data as $usr_id => $fields) {
             // #7264: as we get data for all course members filter against user data
             if (!$this->checkAcceptance($usr_id) || !in_array($usr_id, $usr_ids)) {
                 continue;
             }
             foreach ($fields as $field_id => $value) {
                 $a_user_data[$usr_id]['odf_' . $field_id] = $value;
             }
         }
         // add last edit date
         include_once './Services/Membership/classes/class.ilObjectCustomUserFieldHistory.php';
         foreach (ilObjectCustomUserFieldHistory::lookupEntriesByObjectId($this->getParentObject()->object->getId()) as $usr_id => $edit_info) {
             if (!isset($a_user_data[$usr_id])) {
                 continue;
             }
             include_once './Services/PrivacySecurity/classes/class.ilPrivacySettings.php';
             if ($usr_id == $edit_info['update_user']) {
                 $a_user_data[$usr_id]['odf_last_update'] = '';
                 $a_user_data[$usr_id]['odf_info_txt'] = $GLOBALS['lng']->txt('cdf_edited_by_self');
                 if (ilPrivacySettings::_getInstance()->enabledAccessTimesByType($this->getParentObject()->object->getType())) {
                     $a_user_data[$usr_id]['odf_last_update'] .= '_' . $edit_info['editing_time']->get(IL_CAL_UNIX);
                     $a_user_data[$usr_id]['odf_info_txt'] .= ', ' . ilDatePresentation::formatDate($edit_info['editing_time']);
                 }
             } else {
                 $a_user_data[$usr_id]['odf_last_update'] = $edit_info['update_user'];
                 $a_user_data[$usr_id]['odf_last_update'] .= '_' . $edit_info['editing_time']->get(IL_CAL_UNIX);
                 $name = ilObjUser::_lookupName($edit_info['update_user']);
                 $a_user_data[$usr_id]['odf_info_txt'] = $name['firstname'] . ' ' . $name['lastname'] . ', ' . ilDatePresentation::formatDate($edit_info['editing_time']);
             }
         }
     }
     foreach ($usr_data['set'] as $user) {
         // Check acceptance
         if (!$this->checkAcceptance($user['usr_id'])) {
             continue;
         }
         // DONE: accepted
         foreach ($usr_data_fields as $field) {
             $a_user_data[$user['usr_id']][$field] = $user[$field] ? $user[$field] : '';
         }
     }
     // Waiting list subscription
     foreach ($sub_data as $usr_id => $usr_data) {
         if (!in_array($usr_id, $usr_ids)) {
             continue;
         }
         $a_user_data[$usr_id]['sub_time'] = $usr_data['time'];
         $a_user_data[$usr_id]['subject'] = $usr_data['subject'];
     }
     $this->setMaxCount(count($sub_ids));
     return $this->setData($a_user_data);
 }
 /**
  * read data
  *
  * @access protected
  * @param
  * @return
  */
 public function readSubscriberData()
 {
     include_once './Services/Membership/classes/class.ilParticipants.php';
     $sub_data = ilParticipants::lookupSubscribersData($this->getParentObject()->object->getId());
     foreach ($sub_data as $usr_id => $data) {
         $tmp_arr['id'] = $usr_id;
         $tmp_arr['sub_time'] = $data['time'];
         $tmp_arr['subject'] = $data['subject'];
         $name = ilObjUser::_lookupName($usr_id);
         $tmp_arr['name'] = $name['lastname'] . ', ' . $name['firstname'];
         $tmp_arr['login'] = '' . ilObjUser::_lookupLogin($usr_id) . '';
         $subscribers[] = $tmp_arr;
     }
     $this->setData($subscribers ? $subscribers : array());
 }