Thursday, June 25, 2009

Jython extension for Apache Axis2

In a earlier post I mentioned that my proposal for GSoC 2009 was accepted. There I didn't give much details on what my project is about. Here is a description of my project.

If you have tried out WSO2 WSF/Jython, you will know that it is based on code-first approach. Web services, is a technology to deliver the architectural style defined in SOA. Although there seems to be a general confusion about the relationship between SOA and Web services, it is important to know that Web services are an implementation methodology that adopts standard protocols to execute SOA. There are two widely used techniques in Web service development, ie.
  1. Code First
  2. Contract First
With the contract-first approach, the contract for the Web service is determined first and then the supporting tools are used to generate the implementation code. In contrast, in the code-first approach, first the implementation code is created and then the Web service development framework is used to produce the contract for the Web service.

In simpler terms; in WSF/Jython what I am doing is asking you to write the web service and the client. Then based on the service, a WSDL is generated and exposed as a Web service. Afterwards jython client can be used to invoke the service (ie. code-first).

When it comes to contract-first it is vice versa of the above scenario. First we will have to take the provided WSDL in to consideration. Then based on this WSDL, the code should be generated. Following are the advantages of using contract first approach.
  • Loose coupling between applications
  • Interoperability between multiple services
  • Abstraction hides underlying implementation details
  • Collaboration and agreement between all parties

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