摘要：The Integration Rules (IRules) Project* provides an active, rule-based approach for supporting event- driven activity in applications involving distributed software component integration. This paper presents the execution model, transaction model, and integration rule execution algorithm of the IRules environment. The paper begins with an overview of the IRules language framework to establish the context for the use of events and rules in the integration process, with Enterprise JavaBeans (EJBs) serving as a component model. The paper then elaborates on the integration rule processing algorithm and execution environment. The rule execution model supports traditional active rule coupling modes, and defines a new immediate asynchronous mode to support concurrent execution of triggered rules and transactions. The transaction model is based on the flexible transaction model, providing a means to coordinate global transaction execution with the transactional features of EJB containers. IRules component wrappers also provide support for the global transaction context as well as the synchronization of method execution with the nested execution of integration rules. The paper defines the semantics of coupling modes in terms of cycles and levels of rule execution, presenting the integration rule processing algorithm for coordinating the execution of events and methods on components with the nested execution of integration rules in the context of the transaction model. The details of the algorithm are presented using Unified Modeling Language (UML) activity diagrams, providing a generic approach that can be used as the foundation for rule processing in other distributed environments. An investment application is used to illustrate the concepts presented in this paper.
