Software Engineering and Middleware

Enterprise applications can be viewed as topologies of distributed processes that access business data objects stored in one or more transactional datastores. There are several well-known topology patterns that help to integrate different subsystems or to improve nonfunctional properties like scalability, fault tolerance, or response time. Combinations of multiple patterns lead to custom topologies with the shape of a directed acyclic graph (DAG). These topologies are hard to build on top of existing middleware and even harder to adapt to changing requirements. In this paper we present the principles of an enterprise application architecture that supports a wide range of custom topologies. The architecture decouples application code, process topology, and data distribution scheme and thus allows for an easy adaptation of existing topologies. We introduce Rl-trees for specifying a data distribution scheme and present rules for RJ-tree-based object routing in DAG topologies.