StrataFrame Forum » StrataFrame Application Framework - V1 » WebForms (How do I?) » Trapping Save() Errors

Trapping Save() Errors

choyt — Wed, 19 Sep 2007 13:54:55 GMT

Hi Folks

I am currently doing something similar to the following on every save() I do.

Select Case Me.Save
Case MicroFour.StrataFrame.Data.SaveUndoResult.AbortedWithBrokenRules
Throw New BrokenRulesException(Me.BrokenRules)
Case MicroFour.StrataFrame.Data.SaveUndoResult.FailedWithExceptions
Throw New ApplicationException("The save failed.")
End Select

I trap for broken rules and bubble them up with one custom exception class, and throw exceptions for the other results. Because of this I wind up with an ugly Case statement for every save. Is there any reason not to move this logic to the ErrorSaving event of the business object's themselves to centralize this or is this just the best way to do it?

Thanks!

Clay

RE: Trapping Save() Errors

StrataFrame Team — Wed, 19 Sep 2007 13:54:55 GMT

Looks good, just make sure that when you throw the exception from within the handlers, that you include the supplied exception as an inner exception in case you need to get back to the stack trace some how.

RE: Trapping Save() Errors

choyt — Wed, 19 Sep 2007 13:42:00 GMT

I really appreciate all your help. This is what I finally came up with. I'm going to put this on all of our base business objects.

[codesnippet]

Public Overrides Function Save(ByVal IsTransactional As Boolean) As MicroFour.StrataFrame.Data.SaveUndoResult

Try
Dim r As MicroFour.StrataFrame.Data.SaveUndoResult = MyBase.Save(IsTransactional)
If r = MicroFour.StrataFrame.Data.SaveUndoResult.AbortedWithBrokenRules Then
Call Utility.SystemUtilities.ErrHandler.BrokenRulesHandler(Me.BrokenRules)
ElseIf r = MicroFour.StrataFrame.Data.SaveUndoResult.FailedWithExceptions Then
Call Utility.SystemUtilities.ErrHandler.SaveFailedHandler(Me.TableName)
Else
Return r
End If
Catch ex As Exception
Call Utility.SystemUtilities.ErrHandler.SaveFailedHandler(ex)
End Try

End Function

[/codesnippet]

The 2 Handler functions basically write to the event log and then rethrow a custom exception to the presentation layer.

RE: Trapping Save() Errors

choyt — Wed, 19 Sep 2007 13:20:08 GMT

Cool...thanks Ben

RE: Trapping Save() Errors

StrataFrame Team — Wed, 19 Sep 2007 13:08:44 GMT

[quote]I'm not tracking on this part...[/quote]

I was just saying that when you create a new business object from our template, it will inherit from BusinessLayer, so you will need to change it so that it inherits from your class, not BusinessLayer. The base class that you create will be excactly like you mentioned... it's a basic business object (that itself will inherit from BusinessLayer).

RE: Trapping Save() Errors

StrataFrame Team — Wed, 19 Sep 2007 13:06:28 GMT

Well, actually, the business object isn't going to ever return FailedWithExceptions from save()... :ermm:

If an exception is encountered from within the save, then the exception will just be bubbled up if the ErrorSavingMode is FailOnError and the return value will be CompletedWithExceptions if the ErrorSavingMode is ContinueOnError. If ContinueOnError is used, then yes, the ErrorSaving event will contain the exceptions thrown.

So, the FailedWithExceptions is used for the SaveByForm() method, not the Save() method. So, if you're going to be saving all of the business objects at once through the form's Save() method, then I you would want to override the SaveByForm() method and do the same thing (but I don't think that one is overridable, so if you're saving through the form's Save() method, then we might need to work out something different).

RE: Trapping Save() Errors

choyt — Wed, 19 Sep 2007 13:00:41 GMT

Hi Ben

I'm not tracking on this part...

[quote]Just make sure to change the Inherits line (or the : line) when you create a new business object from our template.
[/quote]

I generally create my own base classes using your templates then inherit from those.

RE: Trapping Save() Errors

choyt — Wed, 19 Sep 2007 12:55:21 GMT

Thanks Ben

Is the ErrorSaving event the only place I can examine the exceptions that cause FailedWithExceptions?

RE: Trapping Save() Errors

StrataFrame Team — Wed, 19 Sep 2007 12:49:34 GMT

Yep, looks good to me. Centralizes everything nice and neat. Just make sure to change the Inherits line (or the : line) when you create a new business object from our template.

RE: Trapping Save() Errors

choyt — Wed, 19 Sep 2007 10:23:17 GMT

Hi Ben

This is what I've come up with...what do you think?

Public Overrides Function Save(ByVal b As Boolean) As MicroFour.StrataFrame.Data.SaveUndoResult

Dim r As MicroFour.StrataFrame.Data.SaveUndoResult
r = MyBase.Save(b)
If Not (r = MicroFour.StrataFrame.Data.SaveUndoResult.Success OrElse _
r = MicroFour.StrataFrame.Data.SaveUndoResult.Cancelled OrElse _
r = MicroFour.StrataFrame.Data.SaveUndoResult.CompletedWithExceptions) Then
Select Case r
Case MicroFour.StrataFrame.Data.SaveUndoResult.AbortedWithBrokenRules
Dim strJson As String = LitJson.JsonHelper.WriteJsonString(Me.BrokenRules)
Utility.SystemUtilities.ErrHandler.WriteEventLog(strJson, "", Diagnostics.EventLogEntryType.Error)
Throw New Exceptions.BrokenRulesException(strJson)
Case MicroFour.StrataFrame.Data.SaveUndoResult.FailedWithExceptions
Throw New ApplicationException()
End Select
End If

End Function

RE: Trapping Save() Errors

StrataFrame Team — Wed, 19 Sep 2007 09:07:48 GMT

Well, the ErrorSaving event only catches exceptions that are caused during the save, and only if the ErrorSavingMode is set to ContinueOnError. Your best bet would be to create a BoBase class and override the OnBusinessRulesChecked method. If the business rules are broken, then throw your exception containing the business rules.

Another option would be to create the BoBase class and override Save(). Call MyBase.Save() and check the return value within your own Save() and check the select case there. You could even show your form with the broken rules there if you don't mind taking that portion of the UI out of the UI...

RE: Trapping Save() Errors

choyt — Tue, 18 Sep 2007 20:24:00 GMT

Hi All

I wanted to add a little more detail to what I am trying to accomplish.

When performing Save(True) operations on multiple business objects at one time and one of the Save operations fail, I want to rollback the transaction then throw a specific exceptin as described below.

When a save fails due to broken rules, I want to throw a custom exception containing these broken rules to the presentation layer (we are currently converting the broken rules collection to a JSON string and passing that string).
When a save failes due to any other reason, I want to rethrow that exception up the chain
When either of the above happen, I want to write either the exception or the broken rules to the application log. The idea is that our presentation tier validation should nearly eliminate broken rules from being written to the app log (I hope!).

I thought about overriding the Save() method and putting the logic there. I also thought about putting the logic in the Business Rules Checked event but I'm thinking that would miss straight out failures.

What I'm looking for is mostly an idea of what would be the best practice and maybe how others are doing this type of operation,. I hope this makes sense!

Clay