[fdo-internals] RE: FDO RFC 61 ready for review

[Sam Wang]

Hi Dan,

Thanks for  your comments.  I have updated the RFC accordingly.
In order to use FdoNamedCollection which requires that the template argument "OBJ" class must provide method GetName() and CanSetName(). So a new class named FdoSavePoint has to be defined to be used as the element type for the collection.

Thanks,
Sam

-----Original Message-----
From: fdo-internals-bounces at lists.osgeo.org [mailto:fdo-internals-bounces at lists.osgeo.org] On Behalf Of Dan Stoica
Sent: Wednesday, May 25, 2011 10:03 PM
To: FDO Internals Mail List
Subject: [fdo-internals] RE: FDO RFC 61 ready for review 

Hi,

First, the collection has to be a FdoNamedCollection to ensure the uniqueness of the names.

Secondly, it would be more consistent with the FDO API to get this collection from the transaction object and then add to it.

Third, about 'invalid save points': once the user has this collection it's less likely he will rollback to a invalid savepoint. Meaning also the FDO exception you indicate below will not be needed.

In any case, the proposed RFC is missing a section where the usage is illustrated.

My 2c.

Dan. 

-----Original Message-----
From: fdo-internals-bounces at lists.osgeo.org [mailto:fdo-internals-bounces at lists.osgeo.org] On Behalf Of Sam Wang
Sent: Tuesday, May 24, 2011 11:09 PM
To: FDO Internals Mail List
Subject: [fdo-internals] RE: FDO RFC 61 ready for review 

Hi Dan,

I think this can be maintained internally. Once user rolls back to a specific save point, all the save points defined after it will be invalid. Thus for example, if we rolls back to save point #3, and later user rolls back to #4, an FDO exception should be thrown to indicate that save point #4 is no longer valid due to the rollback of save point #3.  

If we are to provide an API to get the list of available save points, I propose that we add an API prototype like:
virtual FdoStringCollection* GetAvailableSavePoints() = 0; 

However my opinion is that users of this API should be aware of the order of save point definition and will not roll back to an invalid save point. So I think this API is more likely to utilize user(even if they had this utility method, they still can pass an invalid save point to rollback method), and I would regard it more like an option than necessary.

Thanks,
Sam

-----Original Message-----
From: fdo-internals-bounces at lists.osgeo.org [mailto:fdo-internals-bounces at lists.osgeo.org] On Behalf Of Dan Stoica
Sent: Wednesday, May 25, 2011 10:07 AM
To: FDO Internals Mail List
Subject: [fdo-internals] RE: FDO RFC 61 ready for review 

Hi Sam,

My point is that the proposed API alllows for an a arbitrary number of save points. Meaning the user needs to keep track of them. And no, "release save point" is not necessary since I assume RollBack() is doing this.

Please let me understand: a collection of save points is actually a stack, right? If so then once the user rolls back to the save point #N (where N is the index in the stack) then all the save points with a higher number are dissolved. Therefore I believe a method to get the remaining save points is necessary. 

Thanks,
Dan.
________________________________________
From: fdo-internals-bounces at lists.osgeo.org [fdo-internals-bounces at lists.osgeo.org] on behalf of Sam Wang [Sam.Wang at autodesk.com]
Sent: Tuesday, May 24, 2011 6:44 PM
To: FDO Internals Mail List
Subject: [fdo-internals] RE: FDO RFC 61 ready for review

Hi Dan,

If you look into the RFC you will find that there is already an API proposed to roll back to a save point : FdoITransaction::RollBack(FdoString* savePointName). Do you mean that should be additional API to do something like "release save point" ?

Thanks,
Sam

From: fdo-internals-bounces at lists.osgeo.org [mailto:fdo-internals-bounces at lists.osgeo.org] On Behalf Of Dan Stoica
Sent: Tuesday, May 24, 2011 10:59 PM
To: FDO Internals Mail List
Subject: [fdo-internals] RE: FDO RFC 61 ready for review

Hi,

Shouldn't the API include a method to get back all the added save points? This would allow to programmatically rollback to a save point, I think.

Thanks,
Dan.

From: fdo-internals-bounces at lists.osgeo.org [mailto:fdo-internals-bounces at lists.osgeo.org] On Behalf Of Sam Wang
Sent: Sunday, May 22, 2011 9:42 PM
To: fdo-internals at lists.osgeo.org
Subject: [fdo-internals] FDO RFC 61 ready for review

Hi experts,

FDO RFC 61 is now ready for review. You can find it at http://trac.osgeo.org/fdo/wiki/FDORfc61

Thanks,
Sam
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