code: public static FieldType mapTextFields(FieldType field)
     {
        if (field != null && field.getFieldTypeClass() == FieldTypeClass.TASK)
        {
           TaskField taskField = (TaskField) field;
           switch (taskField)
           {
              case START_TEXT:
              {
                 field = TaskField.START;
                 break;
              }
  
              case FINISH_TEXT:
              {
                 field = TaskField.FINISH;
                 break;
              }
  
              case DURATION_TEXT:
              {
                 field = TaskField.DURATION;
                 break;
              }
  
              default:
              {
                 break;
              }
           }
        }
  
        return field;
     }
docs: In some circumstances MS Project refers to the text version of a field (e.g. Start Text rather than Star) when we
  actually need to process the non-text version of the field. This method performs that mapping.
  
  @param field field to mapped
  @return mapped field