Hello;
I've been playing around with trying to override some behaviours in the
area of "read property" on the data objects, but I think I have come to
the conclusion that the way it is rigged-up makes this a little
difficult. I'd like to suggest a change (which is probably more
appropriate for 3.1 owing to it being a non-trivial change in behaviour)
and I would be interested in any feedback. Here is the text of the
ticket...
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There is an issue that a data object (DO) uses the "readProperty()"
method in its accessors such as "getStartTimestamp()"/"getArtist()"
etc... The "readNestedProperty()" does some extra things like using
reflection to get at non-modelled accessors, but "readProperty()" does
not. This is an inconsistency.
Simply adding the additional reflection to "readProperty()" is not a
good idea because in the case where an object is not yet related to the
model, an infinite loop can result. Particularly in the case where a
data object is not yet added to an object context, the logical condition
around stopping this infinite loop is not able to be identified.
My suggestion is to add a protected "readPropertyStored()" which will be
used by the accessors such as "getStartTimestamp()"/"getArtist()". This
method will ~not~ use reflection, but "readProperty()" will do the
additional reflection if necessary. The "readPropertyStored()" will
continue to invoke "readPropertyDirectly()".
In addition, the "extra reflection" from "readProperty()" would be
serviced through two additional methods on the data object;
readPropertyDerived(..)
For the case of the "readNestedProperty(..)" the use of reflection into
an object which is ~not~ a data object will be serviced through;
readNestedPropertyFromNonDataObject(..)
Together these changes will allow for consistenecy in the 'read
property' behaviour and will also allow third parties to more easily
extend Cayenne's 'read property' behaviors in order to support more
sophisticated 'read property' behaviour.
This is a change in behavior and generated DAO classes would need to be
modified to use 'readPropertyStored()' instead of 'readProperty()'.
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cheers.
--
Andrew Lindesay
www.silvereye.co.nz
