Having the following issues with Web services?:

• Web services' requests cost money and thus results should be stored locally for further processing leading to increased development costs;
• Web services' requests take more time than is acceptable to your applications;
• No transparent error compensation mechanism is available for a case of a data-provisioning Web service failure;
• No middleware available for brokering access to your Web services;
• No middleware available for license-based or user-based Web service delivery and monitoring.

If some of the preceding applies, then SOA Trader Web services commercialization middleware extension may help you.

For the last 3 years SOA Trader has been developing and fine-tuned its Web services commercialization middleware extension for simplifying delivery of services on-demand. While one of the development focuses has been separation of functionial and non-functional specifications (i.e. QoS terms, licencing and subscriptions, etc) of Web services, we have been considering also aspects such as caching, QoS monitoring and error compensation. The result is a proxy-like light-weight servlet, which is easy to set-up and to deploy and provides good-enough performance in industrial settings.

The extension allows separating licencing and subscription options from Web service functionality such that service providers would be able to implement the main functionality of their Web services and all the rest, needed for supporting commercialization, would be provided by the extension. This means that you can shorten your technical service development cycles.

The extension acts as a proxy between Web service endpoints and the client application while providing effective SOAP cashing, service monitoring, service licensing and transparent error compensation. The middleware allows to define subscription packages for web service clients, which are then used to facilitate subscription-based access to particular Web services, if needed. One of the implemented robust and effective error compensation mechanism makes use of the caching functionality to provide results from data-provisioning services, even when the services' endpoints are inoperational. This can be switched on and off either at Web service or operation level similarly to caching mechanisms.

The extension can be seen in action at http://www.soatrader.com where it is used for facilitating access to public Web services. For each registered Web service an endpoint at proxy is constructed and made available for incoming requests. After a license has been acquired from the Web Services Marketplace, it can be used to access subscribed Web services. Service providers at the same time can define subscription packages to their services, which are then aquired by service requesters to access particular services. The QoS of brokered Web services is monitored constantly and published at SOA Trader's Web page along with detailed descriptions of particular services.

Last week, after validating the proof-of-concept in industrial settings over the past 2 years, we finally made the source code available. Since several organizations have indicated their interest in making use of the middleware extension, its source code of version 4.0.0 is now available at http://code.google.com/p/soa-trader-web-services-delivery-middleware/.

Feel free to experiment with this great extension and let me know of your experiences in using it.