Research On Coordination Mechanism For Resource Access Within Distributed Applications

Web Services Composition has become an important way for constructing cross-enterprise applications. Facing spontaneous business requirements, the distributed application based on Web Services project brings forward the business collective technology to support semantic sharing and an event-driven approach to dynamic alliance creation which integrates services from different parties to form business processes. But the business processes may be long in duration, and two or more process instances executing in parallel may attempt to operate on the same resource, causing inconsistencies and resulting in that the processes can't run as expected.Traditional concurrency control methods can't be well applied to resolve these problems in a loosely-coupled environment. The application constructor has no central control on resources provided by autonomous business entities. Since the business process is long-running, the providers may not be willing to lock resources exclusively for such long period, and serialization by locking resource will raise serious scalability issues. The thesis proposes a light-weight coordination mechanism for distributed application manufacturing-oriented, which insures the consistencies of resource status while not bringing down the concurrency rate. The major contributions of this thesis are as follows:It proposes a coordination protocol, which manages the message exchanging about resource operation between client application and resource owners, and provides the applications with consistent resource status. The resource providers can retain control of their resources while taking part in multiple coordination instances.It analyzes the WS-Coordination specification and tries to use it in distributed application manufacturing-oriented to achieve agreement between the services that composing the processes and make them execute as a whole. The protocol...