Re: Cleaning a space

Logan, Patrick wrote:
>> As for using httpmd or changing jar file names to get Outrigger to
>> recognize new entry schemas, that won't work since Outrigger does
>> all of its class matching baised only on class names, not class
>> name/codebase pairs.
>
> Does Blitz behave the same way? Is this a gap in the javaspaces spec?
>

Yes and.....

No - or rather it might be a gap but you would also have to plug a gap
in codebase handling in general.  That would be because one cannot
safely infer anything about versions or similarity of classes from the
codebase.

As it happens, I actually founded a company to handle precisely these
issues along with Nigel Warren but that was a few years back now and
people weren't even aware the problem existed at that time.

Might be time to go dust off that material and try again.......

> So there is no way to have instance1 of version1 of class C in the
> space at the same time as instance2 of version2 of class C?
>

Well, even if that were possible you have some other things to consider
like what the matching semantics should be.  Should clients with the old
schema be able to somehow cope with the new, how long will this
"overlap" exist etc.

Also, there are other means of handling this kind of migration issue
which require no changes to codebase handling or the 'spaces spec.

> What about the situation where the above instance1 is taken, there are
> no more instances of version1 of class C in the space, and then along
> comes instance2 of version2? Will Outrigger want to use version1 of
> the class? Wha'happen?
>

Once Outrigger has "seen" a class with name X, it will assume all X's
have the same structure, same for Blitz.

As an aside, note that co-existence of multiple versions can be quite
costly performance wise for matching etc.

Dan.

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