Reflective Hierarchical State-Machines for Self-Adaptable Distributed Transaction Coordination

Current transaction processing systems often lack the desired property to adapt their behavior to the ever-changing environment and the run-time context. Concerning a particular application domain, there could be various extended transaction coordination models, each focusing on solving specific problems. However, they are usually not targeted to manage the complicated situations with a mixture of these problems. Providing an overall transaction model for such mixture of problems is impractical, if not impossible. Our solution to this challenging issue is to build a self-adaptable transaction coordination framework. Rather than providing yet another transaction model, this framework hosts different transaction coordination protocols in the existing transaction patterns, and makes them adaptable according to the changing application context. Transaction coordination systems can choose their desired transaction patterns at the beginning of transactions, or switch their patterns at run-time if necessary. To make this possible, a formal hierarchical state-machine is incorporated into the framework, and reflection method is adopted. Experimentation of this framework is based on J2EE activity services. Mobile transaction coordination scenario is used throughout the paper as an illustration of how the framework may be applied practically