web service composition

[hemamalini nithyanandam]

i am doing a project on qos based web service composition. i created web services using tomcat , axis2 . using quality metrics of web service like cost, availabilty ,etc i ranked those services based on user request. now i need to compose web services based on user request. i am just a beginner in web services. can any one provide me any useful link or book to compose web services using java

[Tim Moores]

Possibly a case for BPEL. Check out Apache ODE for an implementation.

[hemamalini nithyanandam]

thanks for the reply. can i do without bpel?

[Tim Moores]

Sure. Any BPEL implementation is just code, the functionality of which (or a suitable subset of it) you can implement on our own. You'd have to think (and implement) about how to orchestrate various WS, though - for example, how the output of one WS might be used as the input of the next WS. That's not a trivial task for arbitrary WS. Or do the WS in question have fixed signatures, so that you know exactly what goes in and what comes out?

[hemamalini nithyanandam]

i have created web services for travel reservation system. train/flight/bus services has inputs like source and destination places and these services returns amount which is the input to hotel services. based on the amount returned by hotel services , taxi services are retrieved. i need to orchestrate these three kind of services..

[hemamalini nithyanandam]

will my logic work? can i do composition using those services ? or do i have to change the input and output?

[Tim Moores]

Using can always create a composition of several WS, it's just a question of how much programmatic work it takes to medaite between them. Obviously it gets easier if output objects of one WS can be used as input objects for the next one in line.

[hemamalini nithyanandam]

thanks a lot for your reply. will bpel support qos issues of web service ? can you suggest a good book or link to understand web service composition?i read many papers regarding composition but could not understand how can i achieve composition in my project .

[Tim Moores]

I'd start by installing Apache ODE and working through some of its examples. That should provide you with more insight into BPEL.

[hemamalini nithyanandam]

thanks a lot. i will start working on .