Re: Need some advice on handling EO validation errors

On 7 Dec 2007, at 16:03, 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.

This is good advice.  If you want to discard changes from your editing  
context, use revert(); or, in some cases, refetch() may be appropriate  
- but usually revert() is correct.

> 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?

It is possible to do this.  Implement handleException in your  
Application class; this isn't the best place to handle database  
validation errors, but it's one way of preventing uses seeing the  
famous WO exception page.

Paul