Patterns for monitoring scenarios to handle state based crosscutting concerns

This paper describes two patterns, Scenario Monitor and Bind Completed Scenario to Event. The first allows scenarios to be monitored. The second uses scenario monitoring to address state based crosscutting concerns in traditional data transformational systems. Crosscutting concerns are tangled with core application concerns and scattered throughout a system. Core concerns are monitored for scenarios that represent events of interest to a crosscutting concern. When the monitored scenarios complete an event is injected into a crosscutting state machine that may react by introducing additional behavior. These patterns permit the monitoring and subsequent behavioral reaction in a minimally invasive way with loose coupling. No special tools or languages are required. An example using the approach is presented.