Research On Workflow Modeling, Enactment And Exception Handling

Workflow technology, supported by information technology, provides a whole framework to facilitate the analysis, establishment, management, simulation and enactment of process models for the actual business processes, and becomes one of the crucial technologies for contemporary enterprises in implementing the management and control of business processes. In order to further advance the applicability of workflow technology, this thesis focused on topics about workflow modeling, enactment and exception handling, and contributes the theory approaches and implementation methods as a result. The research is meaningful for the improvement of the application of information technology and the kernel competences for enterprises in our country.Firstly, information about the growth of workflow technology is briefly represented, the development tendencies of workflow technology are summarized and also the reference model of workflow management system is discussed. COM+ technology, an enterprise level distributed software development technology, which is fundamentally used in the implementation of the workflow system is also introduced.In the aspect of workflow modeling, this thesis introduces a flexible workflow meta-model which is capable of tackling the problems related to business events based synchronization, multiple activity instances, service type activities and run-time process modeling. Such favorable features are approached by extending the traditional activity network model with modeling constructs, such as wait connectors, parallel blocks, services and modification blocks. Practical examples show that the meta-model has significant advantages like strong expressive power, flexible modeling methods, and clear and concise model structures.In the aspect of workflow enactment, a realizing architecture of COM+ based distributed workflow system which can achieve the isolationof application, logic and data by a N-tier framework is represented. The performances in reliability, scalability and practicability of the workflow system based on this architecture are further investigated. The application of the architecture in CIMFlow 3.0 workflow enactment system shows that it is applicable for the managements of enterprise business processes. Then, the implementation of CIMFlow 3.0 workflow enactment system is detailed with a practical example to illustrate the usage and the employment method.In the aspect of exception handling, exceptions in workflow system are briefly discussed, then an approach to the exception handling in workflow system which take into account the structured exception handling method in high-level program languages, the transaction features of workflow tasks and the coordination of exception handling in the organization level is represented. This approach unites manual and automatic ways to handle exceptions, extends the traditional mode which handles exceptions with only common activities by introducing notify and script activities, and also supports the propagation of exception and the coordination of handling.