Chapter 16. Introduction
Protocols Included in XTS
- WS-Coordination (WS-C) is a generic coordination framework developed by IBM, Microsoft and BEA.
- WS-Atomic Transaction (WS-AT) and WS-Business Activity (WS-BA) together comprise the WS-Transaction (WS-T) transaction protocols that utilize this framework.
Note
Properties of Web Services
- Application components that are exposed as Web Services may be owned by third parties, which provides benefits in terms of cost of maintenance, but drawbacks in terms of having exclusive control over their behavior.
- Web Services are usually remotely located, increasing risk of failure due to increased network travel for invocations.
16.1. Managing service-Based Processes
The application in question allows a user to plan a social evening. This application is responsible for reserving a table at a restaurant, and reserving tickets to a show. Both activities are paid for using a credit card. In this example, each service represents exposed Web Services provided by different service providers. XTS is used to envelop the interactions between the theater and restaurant services into a single (potentially) long-running business transaction. The business transaction must insure that seats are reserved both at the restaurant and the theater. If one event fails the user has the ability to decline both events, thus returning both services back to their original state. If both events are successful, the user’s credit card is charged and both seats are booked. As you may expect, the interaction between the services must be controlled in a reliable manner over a period of time. In addition, management must span several third-party services that are remotely deployed.