code: protected ItemState getLastItemState(String identifer)
     {
        List<ItemState> allStates = changesLog.getAllStates();
        for (int i = allStates.size() - 1; i >= 0; i--)
        {
           ItemState state = allStates.get(i);
           if (state.getData().getIdentifier().equals(identifer))
              return state;
        }
        return null;
     }
docs: Return last item state in changes log. If no state exist return null.
  
  @param identifer
  @return