Exception Handling Through a Workflow

Abstract

Abstract. Exception handling is a fundamental functionality of workflow management systems (WfMS). User involvement in exception handling is recognized as critical in various situations due to the unpredictability nature of the exceptions that can occur in a running workflow (WF) engine. The problem however is how to orchestrate human ad hoc interventions with a minimum impact on system integrity. The control flow and data integrity dimensions of the impact are analyzed. Our perspective is to allow the maximum latitude possible to user interventions while keeping system correctness. We propose a solution that uses a WF to guide users handling WF exceptions. Furthermore, we extended the WF engine with a propagation mechanism allowing users to involve multiple members of the organization in the exception handling WF. This solution is implemented in the OpenSymphony (OS) platform. The implementation details of the proposed solution in the OS platform are also given in the paper.

Enhancing Web Service Composition by Means of Diagnosis

“…For instance, [16] proposes a mechanism based on spheres of atomicity and exception handlers to enable a workflow system to recover from expected failures and compensate activities. Moreover, [17] presents strategies enabling human users to participate in the recovery of a workflow instance during the service execution. Other works provide classifications of exceptions, in order to propose suitable recovery strategies; e.g., see [18] and [17].…”

“…Moreover, [17] presents strategies enabling human users to participate in the recovery of a workflow instance during the service execution. Other works provide classifications of exceptions, in order to propose suitable recovery strategies; e.g., see [18] and [17]. In comparison, the novelty of our work is to bind the execution of handlers to the causes of exceptions, by exploiting diagnostic reasoning mechanisms.…”

Fault Tolerant Web Service Orchestration by Means of Diagnosis

“…see [14,11]. Several classifications of exceptions in categories have been made; e.g., see [9], [18] and [13]. These studies report a wide variety of events triggering the exceptions.…”

“…For instance, [11] presents a technique based on spheres of atomicity to handle transactions. Moreover, [13] presents strategies enabling human users to participate in the recovery of a workflow instance during the service execution. Furthermore, [9] proposes a classification of activity types on the basis of factors such as the presence/absence of side-effects in compensation, and the development of a smart execution engine which may ignore the failure of non vital actions during the execution of a workflow.…”

A Framework for Semantic Recovery Strategies in Case of Process Activity Failures

“…In most cases forward recovery comprises dynamic modifications of the process instances, e.g. forward or backward jumps in the flow of control (Reichert et al, 2003;Mourao and Antunes, 2004). Except the rule-based approach of AGENT-WORK (Müller, 2004;Müller et al, 2004) it has not been investigated in sufficient detail how to (automatically) determine reasonable ad-hoc modifications as forward recovery solutions.…”