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The Web Service Conversation Language (WSCL) (Banerji, 2002) and the Web service Choreography Interface (WSCI) (WSCI, 2002) offer conversational meta-models that describe the external behaviour of a service in terms of the acceptable sequence of web service invocations. In addition, WSCI supports message correlation, message choreography, and service operation compensation. Web service transaction protocols such as Web Service Coordination (WS-C) (Carera, 2005), Web Service Transaction (WS-T) (WST, 2005) and Business Transfer Protocol (BTP) (Ceponkus, 2002) propose specific conversations that can be used to coordinate interacting parties and provide transactional properties. However, they do not provide a set of relevant abstractions to model service behaviors.
Web Services Transaction Language (WSTL) (Pires, 2003), a language extension over BPEL (Jordan, 2009) that provides transactional description support. WSTL defines its root element, transactionDefinitions, as a direct child of the wsdl:definitions element. The transactionDefinitions element has two child transactionBehavior elements each containing transaction semantics information on the operations supported by that Web service. The transactionBehaviour element has a type attribute whose values can be compensable, virtualcompensable, retriable, and pivot. These values are not much meaningful to the business analyst and the pros and cons of a service with a specific type of behaviour are not visible. The transactional behaviour type or property does not provide any abstraction for the business analyst to choose a service with an appropriate behaviour.
Jiuxin et al. (2010) defined conception-constrained rules for expressing the business logic of a transaction. In the absence of a suitable abstraction, it is a tough task for the business analyst to express the business requirements in the form of constraint rules.