/**
  * Returns an instance of class (singleton pattern implementation).
  *
  * @return BOL_AuthorizationModeratorPermissionDao
  */
 public static function getInstance()
 {
     if (self::$classInstance === null) {
         self::$classInstance = new self();
     }
     return self::$classInstance;
 }
 public function deleteGroupByName($groupName)
 {
     $group = $this->groupDao->findByName($groupName);
     if ($group !== null) {
         if ($group->isModerated()) {
             $this->moderatorPermissionDao->deleteByGroupId($group->id);
         }
         $actions = $this->actionDao->findActionListByGroupId($group->id);
         if (!empty($actions)) {
             foreach ($actions as $action) {
                 $this->deleteActionById($action->id);
             }
         }
         $this->groupDao->deleteById($group->id);
     }
 }