Re: Need help about code mobility

Andrea Angeloni wrote:
>> I'm not familiar with the example but I would imagine the producer
>> process has a direct dependency on PrimeJob in that it uses it's
>> constructor and fills in the fields.
>
> yes, this is the case under the producer:
>
> PrimeJob job = new PrimeJob(nextNumberToCalculate);
>

So that's going to need to be in the classpath, then.

>> With that being the case, setting java.rmi.server.codebase doesn't help
>> because that will be applied to outgoing classes, not incoming ones.
>
> This is a very big surprise for me, I thought that codebase setting is just
> like a "classpath setting". I've learnead about RMIClassloader annotation,
> but I 've never considered this aspect.
>

Well codebase is kind of a classpath but it's a classpath for _remote_
JVM's not the _local_ JVM it's specified against.

>
>> Thus PrimeJob needs to be in the Producer's classpath.  You can likely
>> get the client to download PrimeJob but you'll probably need to adjust
>> the code to not explicitly mention it in it's own code.
>
>> There are methods for modifying the Producer to not need PrimeJob in
>> it's classpath and download it across the net but if all you want to do
>> is see remote code loading at work, modifying the client side will be a
>> lot easier.
>
> The purpose of my study: I'm trying to see if is possibile to use
> RMI/Jini/Javaspaces code downloading feature to develop applications in
> with
> some classes are deployed in a repository, in particular with inheritance
> relations between remote classes. I've considered JavaSpaces, because I've
> found it a little higher level than pure RMI. So, I've started to study the
> possibility to having JavaSpaces entry classes in a remote repository, used
> by applications that use the space.
>

That's a typical usage pattern for both JavaSpaces and RMI.  I take your
point on JavaSpaces being "higher level" - that's true in many cases
(not all!).

I would suggest you go look at some of the compute server examples for
JavaSpaces as they certainly provide demonstrations of the kind of
behaviour you're looking for.

> Can you indicate me a way how I can modify the producer code to have the
> right behaviour?
>

Sorry, no.  I could indeed make the changes but it's more than just a
code change and unfortunately, I have a lot of other things I need to
do.  Hopefully the compute server examples will provide sufficient
detail for you to achieve your goal.

Dan.

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