/**
  * Utilizes add function of TreeSet. If successful, selected item for combo- box implementation is
  * updated to item just added. Event will not be added if a duplicate event is found
  *
  * <p>Model is saved to file after Event is added
  *
  * @param o the event to be added to this implementation
  * @return true if item successfully added (TreeSet parent class' add function returns true).
  *     False otherwise.
  */
 @Override
 public boolean add(T1 o) // Modify to take in Authenication ID for future logging function
     {
   if (super.add(o)) {
     comboBoxModelSelectedItem = o;
     modelListenersNotify();
     ViewerController.saveModel();
     return true;
   }
   return false;
 }
 /**
  * Utilizes TreeSet parent's remove function. If it returns true, item is removed and, if item is
  * selected in combobox model, selected model is updated to first item if size > 0, null
  * otherwise.
  *
  * <p>Model is saved after item is removed
  *
  * @param o the object to be removed from the set
  * @return true if parent class successfully removes the object. false otherwise
  */
 @Override
 public boolean remove(Object o) // Modify to take in Authenication ID for future logging function
     {
   if (super.remove(o)) {
     if (comboBoxModelSelectedItem.equals(o))
       comboBoxModelSelectedItem = ((this.size() > 0) ? this.first() : null);
     modelListenersNotify();
     ViewerController.saveModel();
     return true;
   }
   return false;
 }
 /**
  * Utilizes TreeSet parent's addAll function. If parent function returns true, the set has changed
  * and, as a result, selected item is updated to first item in list and the model is saved to
  * file.
  *
  * @param c Collection of events to be added to model
  * @return true if the set has changed as a result of this call, false if otherwise
  */
 @Override
 public boolean addAll(
     Collection<? extends T1> c) // Modify to take in Authenication ID for future logging function
     {
   if (super.addAll(c)) {
     comboBoxModelSelectedItem = this.first();
     modelListenersNotify();
     ViewerController.saveModel();
     return true;
   }
   return false;
 }