code: public <T extends Item> List<T> getItems(String subscriptionId) throws NoResponseException, XMPPErrorException, NotConnectedException, InterruptedException {
          PubSub request = createPubsubPacket(Type.get, new GetItemsRequest(getId(), subscriptionId));
          return getItems(request);
      }
docs: Get the current items stored in the node based
  on the subscription associated with the provided
  subscription id.
  
  @param subscriptionId -  The subscription id for the
  associated subscription.
  @param <T> type of the items.
  
  @return List of {@link Item} in the node
  @throws XMPPErrorException
  @throws NoResponseException if there was no response from the server.
  @throws NotConnectedException
  @throws InterruptedException