Re: Need some advice on handling EO validation errors
Re: Need some advice on handling EO validation errors
- Subject: Re: Need some advice on handling EO validation errors
- From: Pierre Bernard <email@hidden>
- Date: Fri, 7 Dec 2007 21:56:21 +0100
It is important to see the EOEditingContext as a sandbox. It's the EC
that contains your unsaved changes. It's not the "EOF stack" that is
clogged with pending updates. Other clients of the EOF stack will not
even see your local changes until they are committed.
When saving fails over a validation error, you get a chance to modify
your sandbox until it is in a valid state.
This also implies that your EC should preferably have a rather short
lifespan and a limited scope. E.g. it should no live for as long as
your application instance and carry uncommited data between unrelated
bits of code.
I for one consider the session default editing context to be mostly a
convenience for smaller applications. I use it only to load data that
shares the lifespan of the session. And I never ever use this context
for write operations.
Pierre
On Dec 7, 2007, at 5:03 PM, Alan Ward wrote:
The unsaved objects(s) are still in your EOEditingContext and thus
any future attempts to save
will try to save them again (along with any subsequent changes).
The approach that you describe
below is not the best one. What you want to do is to catch the
exception from ec.saveChanges()
and depending on what caused it either a) fix your code to prevent
it happening, b) modify the
EO's in your EC such that they can be saved or c) revert the EC and
abandon the unsaved changes.
If you do none of the above and keep trying to save that
editingContext then you'll just keep getting
the same error as EOF tries to persist your changes to the database.
Alan
On Dec 7, 2007, at 8:48 AM, Greg Lappen wrote:
Hi all,
I just recently ran into an issue where my application tried to
save a new object to the database, the save failed, and every
subsequent save failed with the same error. It seems that
WebObjects maintains a queue of updates/saves to write to the
database, and when one fails, it essentially clogs up the queue
because WO keeps trying to save it eveytime someone calls
saveChanges() on an editing context. What I'd like to do is set up
a global exception handler in my application that runs whenever an
exception is not caught by my code, and in that error handler I
want to reset the whole EnterpriseObject stack - the cache, the
update/save queue, everything - so that other work in the
application can continue and not worry about cache corruption or
anything like that.
Is this possible to do? Anyone know how to do it?
Thanks so much for any help.
Greg
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