Always all properties changed?

[Robert Handschmann <Ro...@sphinx.at>]

Hi!
I have a general question on how to handle dependent domain object
properties.
I have a stateful domain object that is displayed on a form. 
The domain object has various property setter methods. Some property
setter methods need to modify the value of another property. I.e. set
some default, that the user may overwrite later on.
 
Now the Tapestry framework always sets ALL properties, thus overwriting
automatically filled properties. If the framework would call the setter
methods only on actually modified properties - this would solve the
problem.
What is the correct pattern for such (complex?) user interaction?
 
Thanks for any suggestions,
Robert