  Enterprise Application Integration deals with the problem of connecting
heterogeneous applications, and is the centerpiece of current on-premise, cloud
and device integration scenarios. For integration scenarios, structurally
correct composition of patterns into processes and improvements of integration
processes are crucial. In order to achieve this, we formalize compositions of
integration patterns based on their characteristics, and describe optimization
strategies that help to reduce the model complexity, and improve the process
execution efficiency using design time techniques. Using the formalism of timed
DB-nets - a refinement of Petri nets - we model integration logic features such
as control- and data flow, transactional data storage, compensation and
exception handling, and time aspects that are present in reoccurring solutions
as separate integration patterns. We then propose a realization of optimization
strategies using graph rewriting, and prove that the optimizations we consider
preserve both structural and functional correctness. We evaluate the
improvements on a real-world catalog of pattern compositions, containing over
900 integration processes, and illustrate the correctness properties in case
studies based on two of these processes.
