Hi Adrian,
On Aug 9, 2007, at 5:51 PM, Adrian Wiesmann wrote:
- Typed Keys: Primary keys are generated for all DataObjects and it
would
be possible to use typed keys while programming. (The fill method
in the
table module extension below could be called with a typed key
lowering the
possibility of coding/conversion errors.)
What is a typed key? Is it a custom Java class used for PK? If so,
you sort of can do that by mapping a meaningful PK and using an
ExtendedType to map a custom class for PK.
- Implementation of Table Data Gateway design pattern: The process
to load
and persist data is managed in a typed gateway class so that it
would be
possible to rewrite or add "elements" of a query (think about
filling a
logical unmapped field on a DataObject with a subquery). I know I
could do
something like this with callbacks. But with callbacks I can't
extend the
query for a performant loading of records.
There are two more extension points in Cayenne 3.0 that may help you
to do that - custom queries and ObjectContext decorators (so you may
intercept certain queries/operation and rewrite them to your liking).
So essentially it should be possible to build what you are describing
as a complimentary module to Cayenne first, and then see if it is
worth integrating it in the core.
And: I am currently thinking about completely remodeling DataViews.
One
of the ideas I have is that the UI could be built from an XML
definition
which is transformed into an object tree. That object tree could be
used
by a renderer to generate a Swing interface, an xsl-fo tree (for PDF
generation) or HTML (for webapps). Have you ever thought about
something
like this?
Many people did (I even started a project called JStaple that never
took off). Not sure if anybody succeeded in building something usable
though.
Andrus
