How to provide a cross platform, asynchronous service interface

Question

What is the best way to provide an asynchronous service interface to multi-platform (primarily java and .net) clients? The backend service is implemented in java.

We are looking at asynchronous web service and message queues, but apparently cross platform asynchronous web service* is not supported yet in java (as far as I know) and for message queues, I was not sure which codec/protocol would be best.

*:Cross platform asynchronous web services can be described in WSDL 2.0, but not in WSDL 1.1 (As far as I understand). Now, JAX-WS 2.x does support asynchronous web service, but not WSDL 2.x. So I'm assuming that JAX-WS asynchronous web service's clients have to be JAX-WS clients, and that we can not use.

Thanks in advance!

EDIT: The difficulty here is that the service is asynchronous, and we prefer a callback based interface for efficiency (so we don't want to use 2 calls on a synchronous WS interface, etc.)

Answer 1

Don't know, what's best, but SOAP is a good choice for a Java backend. The messages are xml based (e.g. not restricted to Java platforms) and it is widely used so you get a lot of support, tools and libraries on the net.

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Another idea that might fit your needs: XMPP.

It is definitly asynchronous, client sending a service request (wrapped in a xmpp message) is the callback and doesn't wait for an immediate answer. I've used in a scenario where I send 'service request' from a xmpp client to a server and received the answers, immediately or a bit later, depending on the complexity of the calculation. This was a human-machine interaction but machine-machine should be even easier.

Answer 2

If its messaging, than use a Messagequeue system. like ZeroMQ. they are all cross platform.

otherwise we do it with .net WCF, and use JaxWS from java to test, that the interface is compatible.