code: public Transcripts getTranscripts(EntityBareJid workgroupJID, Jid userID) throws NoResponseException, XMPPErrorException, NotConnectedException, InterruptedException {
          Transcripts request = new Transcripts(userID);
          request.setTo(workgroupJID);
          Transcripts response = connection.createStanzaCollectorAndSend(request).nextResultOrThrow();
          return response;
      }
docs: Returns the transcripts of a given user. The answer will contain the complete history of
  conversations that a user had.
  
  @param userID the id of the user to get his conversations.
  @param workgroupJID the JID of the workgroup that will process the request.
  @return the transcripts of a given user.
  @throws XMPPErrorException
  @throws NoResponseException
  @throws NotConnectedException
  @throws InterruptedException