public void addChatSessionListener(ChatSessionListener listener){
  if ((listener != null) && !mListeners.contains(listener)) {
    mListeners.add(listener);
  }
}

public void addChatSessionListener ( ChatSessionListener listener ) { if ( ( listener != null ) && ! mListeners . contains ( listener ) ) { mListeners . add ( listener ) ; } }
registers a chatsessionlistener with the chatsessionmanager to receive events related to chatsession .
