__NOTOC__
This topic is further information related to the feature of improving ability for a form to reused model content defined elsewhere.

''' Encapsulation '''
* External whole model
* Reuse a model in multiple forms: Attach different UIs to the same whole model
* Separation of concerns: Language-specific models with binds IDs for UI dereferencing 

''' Narrowing-Only Inheritance / Specialization '''  

* Include a base model
* Add additional non-contradictory model content (e.g. non-overriding binds)
* Specialize by additional binds to restrict access, add access, more bind sites for access control
* Specialize with additional instances, actions, submissions to transform back-end transactional data format into format appropriate for UI binding
** In the limit, the UI could be looked at as another reusable component, but for simplicity we will keep that as a separate issue.

''' Fragment Inclusion '''
* Stepping through a process with multiple pages, filling in parts
* Including external content once into a model
* E.g. include a main model plus add some page-specific constraints
* Could be viewed as specialization, but then would be unable to compose a form consisting of multiple bundles of such constraints

''' Adaptations / Composition '''
* Multiple reusable artifacts that characterize each web service
* In a main form, want to pull in these artifacts and talk to them
* Web Services
** Write instances and submission for a web service
** Pull that into larger model
** Copy data to request payload, invoke, copy data from response payload 

''' Fragment Reusability '''
* multiple times in same page
* contextualize fragment content (e.g. starting context node)
* ID space challenge

----
[[Category:XFormsFutureFeatures]]