Peter,
thank you very much.
Martin
Date: Fri, 15 Apr 2011 07:40:42 -0700
From: PETER.KROGH@xxxxxxxxxx
To: eclipselink-dev@xxxxxxxxxxx
Subject: Re: [eclipselink-dev] How does EclipseLink clone objects?
Also, one
more thing...
One of the
other committers reminded me, that one of the other difficult parts is
maintaining referentional integrity.
That is what
the Identity Map is for.
To do a
proper clone, you need to deep copy, that means walking the relationships and
cloning each of them.
EclipseLink's cloning does backup clone and working copy
cloning, and also is optimized to stop at untriggered relationships.
That is likely the complexity that you are referring to.
Note: that
with weaving change tracking enabled, clones are not usually required, as we
track the changes in place.
I hope that
this answer is helpful.
Good
luck.
Peter
Hi
all,
this may be a little strange question, but still. I study at
the Czech Technical University and my bachelor's project is transactional
processing for a persistence layer developed at the university. This layer
control access to ontologies, not relational databases. I got inspired by
the EclipseLink and here's my question:
Can you, please, give me a
little advice about cloning objects? I've developed the Unit of Work system,
quite similar to the one in EclipseLink (but much simpler), but the way
EclipseLink creates clones is quite complex. Is there an easier way to clone
objects? I understand that making shallow copies won't work, but I don't
know how to solve relationships when cloning. Should I clone all the objects
the given one is in relationship with? Or is there another
solution?
Thanks very much
Martin
Ledvinka
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