[gme-users] Nested transactions

[Peter Volgyesi]

I agree with Kevin, you should try to use the Undo() method in
IMgaProject. Keeping track of the number of commits (a single undo()
call will un-do the last transaction) should not be a big a problem.

--
peter



On Fri, Aug 6, 2010 at 9:31 AM, Kevin Smyth <ksmyth at isis.vanderbilt.edu> wrote:
> Another options to consider is undo support, but you would need to keep track
> of how many transactions you'd like to undo.
>
> Kevin
>
> -----Original Message-----
> From: gme-users-bounces at list.isis.vanderbilt.edu
> [mailto:gme-users-bounces at list.isis.vanderbilt.edu] On Behalf Of James H. Hill
> Sent: Thursday, August 05, 2010 9:23 PM
> To: gme-users
> Subject: Re: [gme-users] Nested transactions
>
> Hi Peter,
>
> On 8/5/10 10:27 AM, Peter Volgyesi wrote:
>> Hi James,
>>
>> I wonder what do you gain by having a "root transaction". In your
>> interpreter you can have fine grained transaction logic (I guess we
>> call this "custom transactions" in the interpreter wizard and/or in
>> the componentconfig.h file). So, your interpreter can commit changes
>> any time to trigger the add-ons (and GUI), but why do you need an all
>> encompassing transaction in this case ?
>
> The reason is because I am creating a GUI for entering input the values
> of complex types, such as structs, arrays, and etc. This is a LOT easier
> than using the model and more intuitive from an end-users point-of-view.
> Well, when creating an array of structures, the add-on that is part of
> the language auto-generates the correct elements for a structure once
> you initialize the appropriate reference elements.
>
> Well, the GUI allows you to edit the complex type, which includes the
> arrays by adding/removing/moving elements, without have to go back and
> forth to the model (a very convenient feature). In the case of adding an
> new element to an array and the element is a complex type as well, the
> only way the add-on is able to generated the correct elements for that
> new complex type in the model, which are needed by the GUI to function
> correctly, is for the developer to *close* the GUI, which causes a
> commit. They then must re-open the GUI and continue editing. This
> becomes a hassle when dealing with large models.
>
> Likewise, they may make some updates, but then decide to *cancel* their
> changes. Well, there is now way to *rollback* all those changes without
> forcing the modeler to remember what happened since the general
> transaction has been committed. It seems this problem would be solved
> with nested transaction support.
>
> This is some functionality that our sponsors would like to have to make
> the DSML we created more user-friendly. It is unknown how to make it
> happen without support for nested transactions, or trying to emulate
> them ourselves.
>
> Or, any suggestions are welcome.
>
> Thanks,
>
> James
>
>>
>> --
>> peter
>>
>>
>>
>> On Thu, Aug 5, 2010 at 7:52 AM, James H. Hill<hillj at cs.iupui.edu>  wrote:
>>> Hi Peter,
>>>
>>> Ah, I see. Thanks for the quick reply.
>>>
>>> Are there any plans to make sure a feature available in interpreters? I can
>>> see a case were you may have an interpreter that:
>>>
>>> . starts a root transactions
>>> . makes incremental updates to the model in nested transactions
>>> . commits its current modifications to force the *add-on* to execute
>>> . commits root transactions once everything is complete
>>>
>>> I would think that nested transactions would make this use cause much
>>> easier
>>> to implement without *duplicating* a LOT of code. Or, do you know a
>>> workaround for *emulating* nested transactions in interpreters to prevent
>>> duplicating a LOT of code or causing tight coupling of code?!
>>>
>>> Thanks,
>>>
>>> James
>>>
>>> On 8/5/10 8:42 AM, Peter Volgyesi wrote:
>>>>
>>>> Nested transactions are used only inside MGA (to implement add-on
>>>> notifications in which add-on can further modify the models).
>>>> --
>>>> peter
>>>>
>>>>
>>>>
>>>> On Wed, Aug 4, 2010 at 5:23 PM, James H. Hill<hillj at cs.iupui.edu>
>>>> wrote:
>>>>>
>>>>> Hi,
>>>>>
>>>>> Does anyone know if GME supports nested transactions in it's
>>>>> interpreters, and how to do so?!
>>>>>
>>>>> I see that there is an enumeration value TRANSACTION_NON_NESTED, but
>>>>> there is no TRANSACTION_NESTED value. I only see TRANSACTION_GENERAL,
>>>>> which seems to not support nested transactions.
>>>>>
>>>>> Any help would be greatly appreciated.
>>>>>
>>>>> Thanks,
>>>>>
>>>>> James
>>>>> _______________________________________________
>>>>> gme-users mailing list
>>>>> gme-users at list.isis.vanderbilt.edu
>>>>> http://list.isis.vanderbilt.edu/mailman/listinfo/gme-users
>>>>>
>>>
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