Adds a change listener to the list of listeners.

@param listener
The listener added to the list
190936
public void addCDKChangeListener(ICDKChangeListener listener) {
        if (listeners == null) {
            listeners = new ArrayList<ICDKChangeListener>();
        }
        if (!listeners.contains(listener)) {
            listeners.add(listener);
        }
    }
496563
public static <L, K> void addListener (Map<K, ListenerList<L>> map, K key, L listener)
    {
        ListenerList<L> list = map.get(key);
        if (list == null) {
            map.put(key, list = new ListenerList<L>());
        }
        list.add(listener);
    }
437817
public function addListener(string $event, $listener)
    {
        if (!isset($this->listeners[$event])) {
            $this->listeners[$event] = [];
        }
        $this->listeners[$event][] = $listener;
    }
679473
public void addListener(InvalidationListener listener) {
        synchronized (hsInvalidationListeners) {
            hsInvalidationListeners.add(listener);
            invalidationListenerCount = hsInvalidationListeners.size();
            bUpdateInvalidationListener = true;
        }
    }
1223595
@SafeVarargs
    public final void addCalendarListeners(ListChangeListener<Calendar>... listeners) {
        if (listeners != null) {
            for (ListChangeListener<Calendar> listener : listeners) {
                getCalendars().addListener(listener);
            }
        }
    }
1335707
public void addSelectionChangedListener(ISelectionChangedListener listener)
	{
		if (fOutlineViewer != null)
		{
			fOutlineViewer.addSelectionChangedListener(listener);
		} else
		{
			fSelectionChangedListeners.add(listener);
		}
	}
303482
public void setListeners(java.util.Collection<Listener> listeners) {
        if (listeners == null) {
            this.listeners = null;
            return;
        }

        this.listeners = new com.amazonaws.internal.SdkInternalList<Listener>(listeners);
    }
475400
public CheckBox addListener(Listener listener) {
        if(listener != null && !listeners.contains(listener)) {
            listeners.add(listener);
        }
        return this;
    }
96462
public void addListener(ISUPListener listener) {
        if (listener == null) {
            throw new NullPointerException("Listener must not be null!");
        }
        if (this.listeners.contains(listener)) {
            throw new IllegalArgumentException("Listener already present: " + listener + " !");
        } else {
            this.listeners.add(listener);
        }

    }
1122316
public void removeReferenceListener(ReferenceListener listener) {
		final List<ReferenceListener> list = this.listeners;
		if (list != null) {
			synchronized (list) {
				list.remove(listener);
				if (list.isEmpty()) {
					this.listeners = null;
				}
			}
		}
	}
1070734
public synchronized void addWeakListener(L listener) {
    Preconditions.checkNotNull(listener);

    _log.info("Adding a weak listener " + listener);
    _autoListeners.put(listener, null);
  }
385387
public synchronized void addPropertyChangeListener(java.beans.PropertyChangeListener listener)
    {
        if (propertyChange == null)
            propertyChange = new java.beans.PropertyChangeSupport(this);
        propertyChange.addPropertyChangeListener(listener);
    }
381946
public void addListener(AnimatorListener listener) {
        if (mListeners == null) {
            mListeners = new ArrayList<AnimatorListener>();
        }
        mListeners.add(listener);
    }
588331
@SuppressWarnings("WeakerAccess")
    public void addChangeListener(@NonNull ControllerChangeListener changeListener) {
        if (!changeListeners.contains(changeListener)) {
            changeListeners.add(changeListener);
        }
    }
467222
public void addlistener(final ChangeListener listener) {
        synchronized (LISTENER_LOCK) {
            if (listeners.contains(listener)) {
                LOGGER.warn("Skip listener registration. listener[" + listener + "] is already registered!");
                return;
            }
            listeners.add(listener);
        }
    }
525885
public void addListener(WindowListener<K,R,P> listener) {
        this.listeners.addIfAbsent(new UnwrappedWeakReference<WindowListener<K,R,P>>(listener));
    }
372524
public void addAStarListener(AStarListener<ST, PT> listener) {
		if (this.listeners == null) {
			this.listeners = new ArrayList<>();
		}
		this.listeners.add(listener);
	}