Re: Reshaping the JavaSpaces architecture. Just some thoughts ...

Hi Gregg,

I see that I wasn't specific enough in my last post to this mailing 
list. I'll try to be more precise while still doing some brain storming. 
One idea I'm juggling in my mind is to tear JavaSpaces apart and have an 
open system consisting of various sub-systems based on open-source 
technology. The approach of having a coherent system for space-based 
computing is a good idea as such. But I'm afraid that this approach 
nowadays hinders JavaSpaces from spreading any further. People simply 
won't chose a single system that does it all any more that in addition 
is tied to some specific distributed computing paradigm. They want 
loosely coupled systems they can combine.

A wild idea of mine would be to pick some distributed cache system 
(JBoss Cache, EHCache, SwarmCache or whatever) and place a 
JavaSpaces-like layer on top that provides write/take/read/notify 
functionality. Let's add a service provider interface for the 
distributed cache system so that the cache system could be replaced with 
any other one. If possible use JNDI instead of Jini. My knowledge of 
Jini is too limited to tell whether that is possible at all. I simply 
fear that in an enterprise setting Jini would not be accepted as being 
dead technology. Whether this is true or not won't matter I'm afraid. In 
the J2EE world, for example, people are very sensitive about only using 
the latest technology (even when it is easy to see that it's 
brain-damaged having to implement 4 interfaces to make an object 
persistent as in EJB2). My general idea is to change JavaSpaces so that 
it has a chance in the enterprise computing world. Whether to go with 
RMI or JMS is another issue. Haven't thought much about this so far and 
therefore I will refrain for the time being from expressing an opinion here.

So much for this post. Hope nobody gets mad at me now "attacking" 
JavaSpaces. It's only about exchanging ideas ;-).

Regards, Oliver


Gregg Wonderly wrote:

> This is all possible without changing Javaspaces.  What you are 
> suggesting is the age old "lets make our service do this too" line of 
> thinking.  Instead, the Jini service architecture (and SOA from most 
> perspectives) is "let's add a service to provide this feature".
>
> You can park a Jini service on your network that uses subscriptions on 
> JMS (or MQTT might be better for high volume, non-Java clients), to 
> perform READ/TAKE on the Javaspace, and then forward the appropriate 
> messages to the subscribers.
>
> The "JBoss Cache" business, I'm not sure what you are asking for.  Do 
> you think that there are bandwidth or storage capacity issues with JS 
> that JBoss Cache would solve?
>
> I've not talked about it much lately, but my 
> http://griddle.dev.java.net project is a recast of the Javaspaces APIs 
> with separation of keys from data, and the addition of an iterator 
> (which Javaspaces5 has) and an executor mechanism.  I also removed the 
> use of "marshalled only" tuples, allowing that to be done explicitly 
> if needed, but letting the application decide.  Typically, you'd use 
> native types for keys, unmarshalled, and use marshalled data for the 
> bits you are storing.
>
> The code out there does work, but it's still a preliminary design of 
> the concepts with no attention to performance details.
>
> Gregg Wonderly
>
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