Research And Implement On Handling Cross-cuttings In Web Service With The Aspect-oriented Approach

When introducing aspect-oriented thinking into Web Services, aspects are capable to abstractconcerns from the basic processes which improve the modularity of process definition largely, thenare integrated via weaving technology, which would flexibly deal with the change of requirementsbased on the fact that aspects can be activated and deactivated dynamically. Expectation andrequirement in various phrases of Web Services from clients, as well as the QoS properties andtransaction characteristics that service providers focus on could be described as the cross-cuttings andadded into basic process with aspect-oriented approach. However, traditional aspect-orientedapproach, in which aspects are triggered by the current activity, is not competent to solve someproblems in Web Service compositions such as transaction handling, process’s dynamic evolution.Considering these shortages, the idea of making an extension to WS-BPEL with stateful aspects isput forward at first. The extension to the syntax of WS-BPEL is proposed, which is able to define thecondition to trigger the aspects and abstract cross-cuttings considering process history trace. Whenapplied on the transaction problems, it helps WS-BPEL achieve the transaction whose processingmechanism is based on process trace. Then, runtime weaving of the stateful aspect is implemented.After directed hypergraph is selected as the data structure, the tracing and matching algorithmimplementing the dynamic weaving of stateful aspects is presented. It is independent with thedefinition of processes, introduces new business logic without changing the original process definition,improves the adaption of the process and supports the dynamic evolution of the Web Servicecomposition process. Finally, in order to support the compile of the syntax extension to the WS-BPELand runtime weaving of stateful aspects, the stateful aspects management is extended to the businessprocess execution engine ODE, which cooperates with BPEL compiler to compile process incompile-time and communicates with BPEL engine runtime component in runtime to weave aspectsdynamically.