Re: JMS, RMI and synchronous request-response
On Sun, 10 Aug 2008, marlow.andrew@googlemail.com wrote:
I worked on a java CORBA project once where I was asked to replace
CORBA with JMS. I queried this because the software was using
synchronous request-response which CORBA is very good at. Well the
change went ahead anyway and I don't think the JMS approach was
better. In fact, IMHO in some ways it was worse. Now I find myself on
a java project that is also considering using JMS for synchronous
request-response. My concern is the same issues will be there. The
issues were:
cannot tell when connection between client and server is broken
cannot tell when server is not there
cannot tell the difference between a very busy server and a server
that isnt there
performance issues when large XML messages are exchanged
Yet when I google I find that people do use JMS for request-response.
They point out that JMS can be used for synchronous messaaging. Well,
yes, I do know that. I used it on this CORBA project. But just because
you can do something doesn't mean you should. And then there is lingo
project in codeHaus that offers request-response using JMS. This also
encourages people to look to JMS for solve their request-response
needs.
So I was wondering, what is other peoples experience of implementing
request-response systems in java. Do you use RMI? CORBA? JMS? Lingo? Or
something else?
I haven't really done anything like this, so my knowledge is entirely
academic. But i'd agree that JMS really seems like the wrong tool here.
RMI seems to have only superficial appeal - it looks to me like it won't
handle large numbers of connections well, nor handle fault tolerance and
load balancing. Std CORBA doesnt either but most implementations provide
extensions in these areas.
You can run RMI over IIOP, such that is basically becomes a facade over
CORBA, although i think the ORBs need to support some specific extensions
('objects by value', possibly something else). Would that let you use the
enterprisey features you want from RMI, without the interface complexity
of raw CORBA?
CORBA seems to have gone out of fashion. I think this is a pity coz I
reckon its the closest thing to a solution right now.
I think you're right. There are installations of CORBA doing some pretty
serious work out there in the wild that are the living proof of this. I
know CORBA isn't perfect, and i understand why it didn't become a roaring
success, but what really confuses me is that we've ended up with
alternatives which are more complex and less powerful. What happened?
tom
--
What we learn about is not nature itself, but nature exposed to our
methods of questioning. -- Werner Heisenberg