code: public FieldType getFieldTypeFromVarDataKey(Integer key)
     {
        FieldType result = null;
        for (Entry<FieldType, FieldMap.FieldItem> entry : m_map.entrySet())
        {
           if (entry.getValue().getFieldLocation() == FieldLocation.VAR_DATA && entry.getValue().getVarDataKey().equals(key))
           {
              result = entry.getKey();
              break;
           }
        }
        return result;
     }
docs: Used to map from a var data key to a field type. Note this
  is designed for diagnostic use only, and uses an inefficient search.
  
  @param key var data key
  @return field type