I am trying to use ojb to store objects generated by EMF (framework to generate java source code based on UML/xsd schemas, see the eclipse project).
I have already covered some ground and am able to generate classes from a few simple xsd's (using emf), automatically generate the database scheme using the EMF specific javadoc tags (for all three inheritance mapping strategies), generate the sql files to create the database tables (using torque) and automatically generate ojb descriptor files to map from the tables to the EMF objects.
Simple 1:1 references work (storage and retrieval), in addition storing objects with 1:n references work.
However, retrieving an object with 1:n reference fails, because EMF generated java classes do not have set methods for collection members. Only a get method is generated (with a higher-level interface as the return type). EMF generates the body of the get method and there creates a specific List implementation which is invisible from the outside (therefore I can not use the collection-class attribute in the collection-descriptor).
To get this working I have adapted the retrieveCollection method of the org.apache.ojb.broker.core.QueryReferenceBroker class (as a test).
In this approach I check if the get method of the member returns a valid List class (object) and if so call the add method on this returned List to fill the member.
This works for this test case but is surely not the nicest/most robust approach. Also I (ofcourse) do not want to have my own specific implementation of this ojb class.
What possibly would work better here is sort of collection factory which receives the class descriptor, collection descriptor and the object and returns an empty collection, or even handles the whole add action. This would also be in line with the idea of the object factory which can be registered from the 'outside' (which I also use to get the right EMF objects).
Is this possible in ojb in one way or the other or are there plans to add this?
Or maybe there is another better solution of which I did not think.
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With Regards, Martin Taal
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