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WSDL Faults in Transition Conditions of Workflow Management Systems

IP.com Disclosure Number: IPCOM000028161D
Original Publication Date: 2004-Apr-29
Included in the Prior Art Database: 2004-Apr-29
Document File: 3 page(s) / 41K

Publishing Venue

IBM

Abstract

Workflow Management Systems support the definition and execution of business processes. Business processes are typically described using the Business Process Execution Language (BPEL4WS). A business process consists of a set of activities; the sequence in which the different activities are carried out is defined via control links which connect two activities.The activity where the control link starts is called the source activity; the activity that is the target of the control link is called the target activity. When the source activity has been completed, the flow of control follows the leaving control links to the next activities; a process that is called process navigation or navigation for short. Each control link is associated with a transition condition, a Boolean condition. The control link is being followed when the transition condition evaluates to true. When an activity is implemented as a Web Service defined via WSDL, the executed Web Service may return a WSDL fault. Such a fault causes the process (or scope) to stop and an appropriate fault handler to be activated. Within the fault handler, one can specify how to continue. Thus WSDL faults are handled differently from other business conditions, which are expressed as transition conditions. It is proposed to allow the specification of WSDL faults in transition conditions, making the treatment of conditions more uniform.

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WSDL Faults in Transition Conditions of Workflow Management Systems

    Workflow Management Systems support the definition and execution of business processes. Business processes are typically described using the Business Process Execution Language (BPEL4WS). A business process consists of a set of activities; the sequence in which the different activities are carried out is defined via control links which connect two activities.The activity where the control link starts is called the source activity; the activity that is the target of the control link is called the target activity. When the source activity has been completed, the flow of control follows the leaving control links to the next activities; a process that is called process navigation or navigation for short. Each control link is associated with a transition condition, a Boolean condition. The control link is being followed when the transition condition evaluates to true.

    When an activity is implemented as a Web Service defined via WSDL, the executed Web Service may return a WSDL fault . Such a fault causes the process (or scope) to stop and an appropriate fault handler to be activated . Within the fault handler, one can specify how to continue. Thus WSDL faults are handled differently from other business conditions, which are expressed as transition conditions .

    It is suggested that WSDL faults can be specified in transition conditions as illustrated in the following examples. Suppose we have a process with four activities A, B, C, and D. A is implemented as a Web Service with the following WSDL :

<portType name="A">

<operation name="A">

<input message="msgAIn"/>

<output message="msgAOut"/>

<fault name="FaultA" message="msgAFault"/>

</operation>

</portType>

    The logic of the process is rather simple. Activity A is executed. If a fault occurs, activity B is carried out, otherwise activity C is carried out. After B or C have been carried out, activity D is executed (for simplicity all activities are assumed to be invoke activities). This needs to be modeled as follows:

<links>

<link name="A2C"/>

<link name="B2D"/>

<link name="C2D"/>

</links>

<invoke name="A"

partnerLink="...."

portType="A"

operation="A"

input...