Exception Handling Policies for Composite Web Services and their Formal Description

This paper presents seven exception handling policies for composite Web services and their formal description method, which aims to formally describe events, conditions and states associated with exception handling during composite Web services execution, further to facilitate the implementation of exception handling for composite Web services. The description method is based on the predication logic and statechart. Predication is used to define concepts and statechart is used to describe the execution process of composite Web services. The exception handling policies are described formally according to how and when the exception handling actions are executed. ECA (event-condition-action) rules are used to express the events, conditions and exception handling actions during exception handling. An application case is presented to show how to describe the exception handling policies using our description method.