code: private void add(int field)
     {
        if (field < m_flags.length)
        {
           if (m_flags[field] == false)
           {
              m_flags[field] = true;
              m_fields[m_count] = field;
              ++m_count;
           }
        }
     }
docs: This method is called from the task class each time an attribute
  is added, ensuring that all of the attributes present in each task
  record are present in the resource model.
  
  @param field field identifier