code: public boolean addAll(Object[] listenersToAdd) {
  		if (listenersToAdd == null) {
  			return false;
  		}
  		boolean changed = false;
  		for (int i = 0; i < listenersToAdd.length; i++) {
  			if (add(listenersToAdd[i])) {
  				changed = true;
  			}
  		}
  		return changed;
  	}
docs: Adds all the given listeners to the list of registered listeners. If any of the elements in
  the array are null or are listeners that are already registered, they will not be registered
  again.
  
  @param listenersToAdd The collection of listeners to be added. May be null.
  
  @return true if the list of registered listeners changed as a result of attempting to
  register the given collection of listeners.
  
  @throws IllegalArgumentException if any of the listeners in the given collection are of a
  type that is not assignable to the class of listener that this instance manages.