private void initOtrChatSession(ImEntity participant) {
    try {
      if (mConnection != null) {
        mDataHandler = new OtrDataHandler(mChatSession);
        mDataHandlerListener = new DataHandlerListenerImpl();
        mDataHandler.setDataListener(mDataHandlerListener);

        OtrChatManager cm = service.getOtrChatManager();
        cm.addOtrEngineListener(mListenerAdapter);
        mChatSession.setMessageListener(new OtrChatListener(cm, mListenerAdapter));

        if (participant instanceof Contact) {
          String key = participant.getAddress().getAddress();
          if (!mOtrChatSessions.containsKey(key)) {
            OtrChatSessionAdapter adapter =
                new OtrChatSessionAdapter(
                    mConnection.getLoginUser().getAddress().getAddress(), participant, cm);
            mOtrChatSessions.put(key, adapter);
          }
        } else if (participant instanceof ChatGroup) {
          ChatGroup group = (ChatGroup) mChatSession.getParticipant();

          for (Contact contact : group.getMembers()) {
            String key = contact.getAddress().getAddress();
            if (!mOtrChatSessions.containsKey(key)) {
              OtrChatSessionAdapter adapter =
                  new OtrChatSessionAdapter(
                      mConnection.getLoginUser().getAddress().getAddress(), contact, cm);
              mOtrChatSessions.put(key, adapter);
            }
          }
        }

        mDataHandler.setChatId(getId());
      }
    } catch (NullPointerException npe) {
      Log.e(ImApp.LOG_TAG, "error init OTR session", npe);
    }
  }
  @Override
  public void setDataListener(IDataListener dataListener) throws RemoteException {

    mDataListener = dataListener;
    mDataHandler.setDataListener(mDataListener);
  }