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Subprocess Synchronization in Workflow Management Systems

IP.com Disclosure Number: IPCOM000014027D
Original Publication Date: 2000-Aug-01
Included in the Prior Art Database: 2003-Jun-19
Document File: 7 page(s) / 194K

Publishing Venue

IBM

Abstract

1. Introduction

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Subprocess Synchronization in Workflow Management Systems

1. Introduction

    Workflow management systems [1] manage the execution of business processes. Those business processes are modeled as direct, acyclic, colored and weighted graphs.

1.1. Sequencing Activities

    The major constructs in drawing processes are activities and control connectors. The activities describe the tasks to be performed, and the control connectors describe the potential sequence in which the activities are to be carried out. Figure 1 shows schematically the structure of such a process graph.

Figure 1 Sequencing Activities

    Activities are represented as named circles; the name typically describes the purpose of the activity. Activities come in various flavors to address the different tasks that may need to be performed. They may have different activity implementations to meet these diverse needs. Program activities are performed by an assigned program, process activities are performed by another process, and blocks implement a macro with a built-in do-until loop.

    Control connectors are represented as arrows; the head of the arrow describes the direction in which the flow of control is moving through the process. The activity where the control connector starts is called the source activity; where it ends is called the target activity. When more than one control connector leaves an activity, this indicates potentially parallel work.

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1.2. Making Data Available

    Processes and activities have containers associated with them. These containers are only locally available and not available globally. Thus, the input container of an activity is only available to the appropriate activity. If another activity needs data from a previous activity's output container or from the process input container, this data must be made available to the activity by copying the information from the other containers. Specifying which data needs to be copied from where is the purpose of data connectors . Figure 2 shows how data is copied from the output container of one activity to the input container of the next activity.

Figure 2 Copying Fields Between Activities

    The dashed arrow is the data connector. It indicates that the output container of activity A should be copied to the input container of activity B. The output container of an activity is typically different in structure as are the contained fields from the input container of another activity. Fields may have different names and different types. Thus, the simple specification of a data connector is not sufficient; it is also necessary to specify the appropriate container map. This map specifies which field from the output container is used to fill a field in the input container. The map also specifies what data transformation is to be performed, if any, before the data is stored in the input container.

    Data connectors can not only be drawn between the output contai...