Strategies for Integrating Messaging and Distributed Object Transactions

Messaging, and distributed transactions, describe two important models for building enterprise software systems. Distributed object middleware aims to support both models by providing messaging and transaction services. But while the concept of distributed object transactions is well-understood, support for messaging in distributed object environments is still in its early stages, and not nearly as readily perceived. Integrating messaging into distributed object environments, and in particular with distributed object transactions, describes a novel and complex software design problem. This paper details this problem, presenting first results from our project of developing a messaging and transaction integration facility. The first contribution of this paper is a comprehensive messaging classification framework, which defines messaging concepts and terminology, and enables us to compare different messaging architectures. Second, we analyze sample messaging middleware using this framework, and identify the architectural messaging styles that they induce. Third, we derive four different strategies for integrating messaging and distributed object transactions. We discuss each of these integration strategies, and outline the open research issues that need to be solved. Overall, this paper advances our understanding of the motivation for, the problems of, the current state-of-the-art in, and future models for integrating messaging and distributed object transactions.