code: public void deleteAllItems() throws NoResponseException, XMPPErrorException, NotConnectedException, InterruptedException {
          PubSub request = createPubsubPacket(Type.set, new NodeExtension(PubSubElementType.PURGE_OWNER, getId()));
  
          pubSubManager.getConnection().createStanzaCollectorAndSend(request).nextResultOrThrow();
      }
docs: Purges the node of all items.
  
  <p>Note: Some implementations may keep the last item
  sent.
  @throws XMPPErrorException
  @throws NoResponseException if there was no response from the server.
  @throws NotConnectedException
  @throws InterruptedException