code: public List<ItemState> getItemStates(String itemIdentifier)
     {
        List<ItemState> states = new ArrayList<ItemState>();
        List<ItemState> currentStates = getAllStates();
        for (int i = 0, length = currentStates.size(); i < length; i++)
        {
           ItemState state = currentStates.get(i);
           if (state.getData().getIdentifier().equals(itemIdentifier))
           {
              states.add(state);
           }
        }
        return states;
     }
docs: Gets items by identifier.
  
  @param itemIdentifier
  @return