System integration by developing adapters using a database abstraction

Context: Large software systems are usually developed by integrating several smaller systems, which may have been developed independently. The integration of such systems often requires the development of a custom adapter (sometimes called mediator or glue logic) for bridging any technical incompatibilities between the systems. Adapter development often focuses on how to respond to events from the external interfaces, e.g., by applying data conversions and performing events on (other) external interfaces. Such an operational focus is closely related to an implementation of the adapter, but it makes it complicated to reason about complex adapters. For example, it requires a lot of effort to understand the relation that the adapter establishes between the systems to be integrated, and to avoid any internal inconsistencies. Objective: This article investigates a way to develop adapters in terms of a more abstract, model-based specification. Experts from the application domain should be able to reason about the specification, and the specification should contain enough details to generate an implementation. Method: Based on a few industrial adapters from the domain of Maritime Safety and Security, we study ways to specify them conveniently, and ways to generate them efficiently. On this basis, we identify an approach for developing adapters. In turn, this approach is validated using an additional set of adapters. Results: After abstracting from the details of the interface technologies, the studied adapters could be generated using techniques for incremental view maintenance. This requires an adapter specification in terms of database views to relate the main semantic concepts in the application domain. Conclusion: For developing adapters, it can be useful to model all interface technologies as database operations. Thus adapters can be specified using database views, which improve the conceptual understanding of the adapters. Publish/subscribe-style adapters can then be generated using incremental view maintenance. (C) 2012 Elsevier B.V. All rights reserved.