Simple Web Service in Google App Engine

I would like to have the following functionality implemented in Google App Engine in Java language as a web service: - There will be request from clients via post method to this web service. One of the parameters of the request will be 'url'. [login to view URL]://www.xyz.com/abc&clientcode=abc - Service will look up for data for URL parameter in a database table. url will most probably be the primary key of the table. ---- if it finds it, it will return the data to the client via XML (or JSON). ---- if it cannot find it; it will call another web service on another server on the web using post method, receive data in JSON, parse it and store (insert) it into the table and then return the requested data to the client. There will be other parameters in the call for statistical reasons. These parameters will just be inserted into another table. I would need a simple report for this table as well. I will provide database structure and other details. I will setup a bogle app engine account but since this is the first time, I will need some guidance from the freelancer regarding how to setup and how it works in general.