code: private void populateField(FieldContainer container, FieldType target, FieldType baseline, FieldType actual)
     {
        Object value = container.getCachedValue(actual);
        if (value == null)
        {
           value = container.getCachedValue(baseline);
        }
        container.set(target, value);
     }
docs: Populates a field based on baseline and actual values.
  
  @param container field container
  @param target target field
  @param baseline baseline field
  @param actual actual field