Re: Need some advice on handling EO validation errors

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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