Transactional BPEL Processes with AO4BPEL Aspects

Recently, OASIS approved two standards respectively for Web Service composition and for Web Service transactions. Nevertheless, it is still unclear how WS-BPEL and the WS-TX family of specifications interoperate, i.e., how to use atomic transactions and business activities in the context of BPEL processes. In this paper, we present several transactional requirements in BPEL processes and argue that BPEL's compensation mechanism provides only limited support for a few of these requirements, e.g., it cannot cope with atomic transactions with the ACID properties. To support transactional BPEL processes, we use the AO4BPEL process container framework. In this framework, the transaction requirements of the process activities are specified declaratively in a deployment descriptor and an aspectbased container is generated automatically to integrate the process execution with the transaction middleware, which is provided as a transaction Web Service based on Apache Kandula.