/**
   * Notifies all currently registered {@link CapsVerListener}s that the version hash has changed.
   */
  private void fireCapsVerChanged() {
    List<CapsVerListener> listenersCopy = null;

    synchronized (capsVerListeners) {
      listenersCopy = new ArrayList<CapsVerListener>(capsVerListeners);
    }

    for (CapsVerListener listener : listenersCopy) listener.capsVerUpdated(currentCapsVersion);
  }
  /**
   * Adds <tt>listener</tt> to the list of {@link CapsVerListener}s that we notify when new features
   * occur and the version hash needs to be regenerated. The method would also notify
   * <tt>listener</tt> if our current caps version has been generated and is different than
   * <tt>null</tt>.
   *
   * @param listener the {@link CapsVerListener} we'd like to register.
   */
  public void addCapsVerListener(CapsVerListener listener) {
    synchronized (capsVerListeners) {
      if (capsVerListeners.contains(listener)) return;

      capsVerListeners.add(listener);

      if (currentCapsVersion != null) listener.capsVerUpdated(currentCapsVersion);
    }
  }