java server <-> c# + javascript + java + * clients

What "technology" would you suggest to exchange some kind of messages between a Java server and several clients written in C#, Javascript and Java?

The background story:

In our current project we're trying to build a generic UI backend in Java (running on the server) which is then "bridged" into several UI frontends by means of different UI adaptors (running on the client, the server, or both). While our server technology will always be Java, there will be C# (Silverlight), JavaScript and Java clients. Maybe even more in the future (different Smartphones, Tablets).

The UI backend and UI frontends communicate through a bunch of more or less simple messages (mostly name/value-pairs) each of which encapsulates a specific property/state/data change on the client or server respectively. Within a single request cycle, several such simple messages are aggregated into one big message which is then passed from backend to frontend or vice versa. At the moment sending and receiving messages is done at a single entry point on the client as well as on the server. So there are no server methods exposed as WebService etc. - simply because this would most definitely be to slow in our case.

Our current prototype consists solely of a Java server, a Java Desktop Client (Swing) and a Java Web Client (Vaadin). The message exchanged between backend and frontend is effectively a list of POJOs (each representing a specific "change") serialized/deserialized开发者_如何学Go to/from XML. So far, so good.

Now C# and Javascript come to the table. Since we want to work with some kind of object in each technology, we thought it would be a good idea to specify the messages/changes/pojos in some kind of abstract language and then generate objects for each target language. At some point these objects could then be serialized/deserialized and sent over the wire (probably via http/s). For this purpose we thought of Google's protocol buffers or Thrift. What do you think?

For the moment our synchronous request-response-cycle is enough but we will need asynchronous request-response or server-push respectively pretty soon. That's why we thought of using something like ActiveMQ straight away. What do you think? Too much? If not, how can we accomplish the object generation mentioned above (xsd, jaxb, ? for js)? Are there better ways? I've never used ActiveMQ but according to the website it should be possible with Java, C# (Spring.NET) and somehow with Javascript (STOMP) too. However, this seems pretty complex to me...

Any tips, hints, experiences or comments about this or related topics would be really helpful.

Thank you in advance.

I would recommend using webservices. The WSDL language defines objects and messages of your protocol in abstract form. Most modern languages like Java and C# have tools for converting WSDL to native types and libraries for handling I/O.

For the last two years i have been involved in building a similar system: backend for our project is c#, java and bunch of other languages, frontend is phone clients for ios, android, symbian, all the common webbrowsers and even windows desktop apps.

For all these services we use JSON, since it seems to be most widely supported format across all languages and platforms, it decodes fairly fast on the clients compared to xml based solution (esp. webbrowsers/javascript) and it has a pretty low overhead that compresses extremely well which is great for clients that lack bandwidth.