A pessimistic method in web service composition by view on execution states

摘要

The application of web services in implementing enterprise workflows has recently been prevalent. In this regard, one of the important challenges is to create web service compositions that satisfy quality properties. One of the properties is rollback cost that it must be paid for resolving effects of a web service that its execution is completed. In the previous methods, a web service was evaluated based on whether failure or successful execution state and other two states (in the middle of execution and waiting for execution) were neglected. By considering these two states, it is possible to prevent imposition in a web service rollback cost or reduce it if needed to finally provide the possibility to decrease a web service average rollback cost. Two mentioned states are related to execution time, and it is clear that the proposed solution should be related to execution time. According to implemented tests, the method not only reduces rollback cost but also causes the execution time to reduce. The reduction in execution time parameter is due to necessary waiting for a web service completion before providing the ability to rollback it in conventional methods, but in the method, it is possible to rollback web service before execution completion and waiting for completion is not mandatory.