/**
  * (non-PHPdoc)
  * @see IActionController::executeAction()
  */
 public function executeAction($parameters)
 {
     $user = $this->_websoccer->getUser();
     $teamId = $user->getClubId($this->_websoccer, $this->_db);
     if ($teamId < 1) {
         return null;
     }
     // get unit info
     $unit = TrainingDataService::getTrainingUnitById($this->_websoccer, $this->_db, $teamId, $parameters["id"]);
     if (!isset($unit["id"])) {
         throw new Exception("invalid ID");
     }
     if ($unit["date_executed"]) {
         throw new Exception($this->_i18n->getMessage("training_execute_err_already_executed"));
     }
     // check if minimum time break between two units is matched
     $previousExecution = TrainingDataService::getLatestTrainingExecutionTime($this->_websoccer, $this->_db, $teamId);
     $earliestValidExecution = $previousExecution + 3600 * $this->_websoccer->getConfig("training_min_hours_between_execution");
     $now = $this->_websoccer->getNowAsTimestamp();
     if ($now < $earliestValidExecution) {
         throw new Exception($this->_i18n->getMessage("training_execute_err_too_early", $this->_websoccer->getFormattedDatetime($earliestValidExecution)));
     }
     // check if team is in training camp.
     $campBookings = TrainingcampsDataService::getCampBookingsByTeam($this->_websoccer, $this->_db, $teamId);
     foreach ($campBookings as $booking) {
         if ($booking["date_start"] <= $now && $booking["date_end"] >= $now) {
             throw new Exception($this->_i18n->getMessage("training_execute_err_team_in_training_camp"));
         }
     }
     // check if there is currently a match simulating
     $liveMatch = MatchesDataService::getLiveMatchByTeam($this->_websoccer, $this->_db, $teamId);
     if (isset($liveMatch["match_id"])) {
         throw new Exception($this->_i18n->getMessage("training_execute_err_match_simulating"));
     }
     // trainer info
     $trainer = TrainingDataService::getTrainerById($this->_websoccer, $this->_db, $unit["trainer_id"]);
     $columns["focus"] = $parameters["focus"];
     $unit["focus"] = $parameters["focus"];
     $columns["intensity"] = $parameters["intensity"];
     $unit["intensity"] = $parameters["intensity"];
     // train players
     $this->trainPlayers($teamId, $trainer, $unit);
     // update execution time of unit
     $columns["date_executed"] = $now;
     $fromTable = $this->_websoccer->getConfig("db_prefix") . "_training_unit";
     $whereCondition = "id = %d";
     $this->_db->queryUpdate($columns, $fromTable, $whereCondition, $unit["id"]);
     // success message
     $this->_websoccer->addFrontMessage(new FrontMessage(MESSAGE_TYPE_SUCCESS, $this->_i18n->getMessage("training_execute_success"), ""));
     return null;
 }