Transactions in software components: Container-interposed transactions

The paper focuses on transaction context propagation in component-based software architectures, where every component is deployed into a container and client requests may be performed in the scope of a container-interposed transaction. In the existing commercial architectures such as EJB and COM+, the “single attribute approach” is used to specify the transaction context propagation. Being difficult to comprehend, this specification is also not powerful enough to express all the possible transaction propagation policies even for the flat transaction model; advanced transaction models cannot be employed at all. Moreover, the specification takes place as late as at the deployment time so that it is hard to reflect a particular transaction propagation policy in the component code. As a remedy, we propose to specify transaction propagation policy as a part of a component interface by means of a straightforward double attribute (NT&CT) approach. This way, advanced transaction models based on intertransaction dependencies, giving permissions, and delegation can be also specified.