Evolution Metrics for a BPEL Process

A Business Process Execution Language (BPEL) process in Service-Oriented Architecture (SOA) evolves over time. The study of evolution helps in analyzing the development and enhances maintenance of a BPEL process. In this paper, we study the evolution using metrics which measure the changes and the quantity in which the changes have occurred. A process could evolve on its own or because of the evolution in the partner services. In both the cases, changes could be to the internal logic of the process or involve changes in the interaction with the partner services. The evolution metrics proposed in this paper are—BPEL Internal Evolution Metric (BEM _I ) and BPEL External Evolution Metric (BEM _E ). The time complexity for computing the metrics is linear. The metrics are theoretically validated using Zuse framework and are found to be above the ordinal scale. In our previous work, metrics were proposed for a single service under evolution. The cohesiveness, between the changes of an evolving service and an evolving BPEL process which uses this service, is demonstrated using metrics.