Re: [OJB-developers] conditional persistence of objects

[Thomas M. <tho...@ho...>]

Hallo Bastian,

Bastian Schmitz wrote:
 > hi you OJB developers, i've bee working with OJB for a couple of
 > months now and in my opinion you are performing great work.
 >
thanks,

 > in my application's datamodel there are many objects (A) that reside
 > in a default, dummy or empty state at runtime and i would like them
 > not being persisted, when all the other objects (B) around them are
 > stored in the database and all references / fks to them stored as SQL
 > NULL values.

reference-descriptors and collection-descriptors pointing from B to A 
must be set to
auto-update="false"
to avoid cascading storing of A objects! This can be done quite easily 
with existing OJB API at runtime.
(start with broker.getClassDescriptorFor(B.class))

 > on the other hand, on matialization of objects B
 > containing NULL references / fks to A's, these references should be
 > filled with dummy A's.

OJB provide InstanceCallbacks. Let your class B implement the interface 
ojb.broker.PersistenceBrokerAware

you can put your initialization code in the method afterLookup().

 > the A objects have a method that "decides"
 > whether these objects should be persisted or not. this "mechanism"
 > should also work with collection descriptors.
 >

can be done as described above.

cheers,
Thomas


 > now, my question is how this behaviour could be realized with OJB and
 > where are the "right" starting points for this.
 >



 > thanks in advance bastian schmitz
 >
 >
 >
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