JXTA based parallel service invocation model for peer to peer web service composition

When numerous web services are available, it seems natural to reuse existing web services to create a composite web service. A pivotal problem of web service composition is how to model input and output data dependencies of candidate web services to form composite web services efficiently. In a sequential web services invocation model, each web service needs to wait till the previous web service provides its output for the web service to be invoked, even if they don´t have any inter dependency. Hence they are very poor in resource utilization. Peer to peer network provides certain interesting capabilities such as fault tolerance, high scalability which are not possible in traditional client/server network architecture. JXTA holds tremendous promise for the P2P world. It defines a set of protocols that developers can use to build almost any P2P application. For P2P applications which perform a lot of web service transactions, the use of sequential service invocation architecture may become a limiting factor. This research is made to introduce parallel service invocation model and web service composition model to JXTA. XML tree based notation is introduced to represent a composite web service in JXTA peer environment. The model is implemented by using Java, XML RPC, AXIS2, JXTA and JXTA-SOAP technologies.