Adding a WCF reference to a j2me project

Question

I have a wcf serivce I want to consume from a j2me application (blackberry).

I have been going crazy since the tools that work fine for the j2SE used for consuming web services do not work all that well for j2me. At least not with my service.

I found a useful tutorial at http://www.netbeans.org/kb/60/mobility/mobile-dilbert.html

While it uses an old asmx service style to explain it. I was able to follow the steps and use my wcf reference and I was able to make the connection.

The drawback, this solution uses a j2ee proxy to get the reference to work.

Is this the way to solve the incompatibilities between .net and java? I read that a big reason why this happens is that Microsoft generates non-standard wsdl files for services.

My question is: is this the solution generally used for consuming .net web services from java, or is there a better way? Any reference pointers will be greatly appreciated.

Answer 1

Sebastian,

The only complaints I've heard about non-standard Microsoft WSDL have been complaints that the WSDL is not flat. That is, one WSDL may refer to another WSDL or to an XML schema defined in another file. Some platforms can't handle that. In particular, I recall that one such complaint was from someone doing smart device development. I don't recall if it was j2me.

There's not meant to be anything special to do. ASMX services are very basic old-style SOAP services; WCF additionally supports the WS-* standards. But they should all play nicely together.

Can you say exactly what problem you had when you were having trouble getting it to work with j2me? Please post all the exceptions, error messages, etc. Hopefully, any that need translation from Java into .NET, I'll be able to get some help with.

Answer 2

Hi Sebastian,

Firstly, did you configure the WCF service to use basicHttpBinding?

Secondly, use only native data types (strings, int, bool, etc.) in the data contract. Don't use .NET objects like DateTime etc. This is what I did when I had to develop a MIDLet twitter app that calls a WCF service to get friend updates, post tweets etc... Oh and I also used Wireless Toolkit (v 2.5.2) stubgenerator to create the client. It didn't have any problem creating the client even if the WCF's wsdl had external imports (wsdl:import and xsd:import)

Answer 3

Thank you to the two people who answered, gave me things to think about when doing additional research.

Since there was no definite answer on this question, perhaps I was not clear, and after looking into the subject from other sources. I decided to post what I had discovered.

Looking at the most basic WCF service, one that has one method, returns a string. No other methods in place. Got the errors while adding the reference.

JSR-172 does not understand guids (the idea of the message not the actual message). Same thing for char and duration.

I read about it further and found references on microsoft non standard wsdl files, and that by implementing some interfaces you could remove all non standard schema references from the generated wsdl file.

This helped for a simple service not a complex one.

I tried an existing service, I decided to use the amazon.com affiliate services to test things.

Similar error as with my wcf service, it gave a whole list of types it did not like.

In the end I learned. Visual studio spoils you and makes you lazy(not always a bad thing). I wanted a way to use some sort of wizard type tool, input a reference and get lots of generated code that calls my service, gives my objects to deal with and methods to call.

Netbeans did this for me for J2SE not for j2me.

If you want to use WCF directly for a j2me project, be ready to write all the plumbing code for it.

Alternatively you can use the suggested method of using j2ee proxy. As explained in http://www.netbeans.org/kb/60/mobility/mobile-dilbert.html

With this method you still need to be careful what data types you use. As some cause the service to fail or be unusable. Example, i had a method return a datetime, netbeans would not even let me select that method for stub generation. and calling methods in the service with that one present caused exceptions to be thrown. (method removed and calls succeeded)