A Middleware for Controlling the Execution of Composite Services

A composite service consists of many Web Services. The execution of a composite service is conducted by an execution engine according to the workflow specification. Since different composite services might share and access some of the Web Services concurrently, ensuring the correctness of the concurrent execution of the composite services becomes an important issue. This paper proposes a concurrency control scheme for executing transactional composite services. The scheme is implemented as a middleware. It uses the information gathered from the workflow specifications of the composite services to guarantee the correctness of the execution of the composite services. The proposed scheme avoids the repeated rollback problem facing most existing concurrency control schemes, and, it is more suitable for the clients who use handheld devices to access the Web services.