Implementing Web service protocols in SOA: WS-Coordination and WS-BusinessActivity

Web service protocol standards should be unambiguous and provide a complete description of the allowed behavior of the protocols' participants. Implementation of such protocols is an error-prone process, firstly because of the lack of precision and completeness of the standards, and secondly because of erroneous transformation of semantics from the specification to the final implementation. Applying the TLA+ paradigm we first consider the protocol on an abstract level. Safety properties taken from real world scenarios are compared to the facilities of the protocol. As result, we identified some limitation of applicability of the WS-BA protocol to abstract application use cases, modelled from the real world scenarios. These limitations are an omission of possible activities seen in the real world. Further WS-C and WS-BA make assumptions about the internal structures of the participants, violating SOA paradigm. The former error could be detected by the use of formal methods. The latter can be circumvented by a sophisticated implementation strategy. The proposed strategy of implementing WS-Coordination and WS-BusinessActivity allows non-intrusive integration of the transactional framework, considering SOA requirements. This paper describes the results of analysis and some design decisions taken during the proof-of-concept implementation of WS-C and WS-BA frameworks.