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Thursday, 13 June 2013 11:03

Pattern PP1: Late Selection of Process Fragments

This pattern allows deferring the selection of the implementation of a particular process activity to run-time. Prior to execution only a placeholder activity has to be provided, the concrete implementation is selected during run-time either based on predefined rules or on user decisions (Design Choice A). The placeholder activity can either be substituted by an atomic activity or a sub process (Design Choice B). This is done before the placeholder activity is enabled or when it is enabled (Design Choice C).

Description

For particular activities the corresponding implementation (activity program or sub process model) can be selected during run-time. At build-time only a placeholder is provided, which is substituted by a concrete implementation during run-time

Example

For the treatment of a particular patient one of several different sub-processes can be selected depending on the patient’s disease.

Problem

There exist different implementations for an activity (including sub-processes), but for the selection of the respective implementation run-time information is required.

Design Choices 

  1. How is the selection process done?
    1. Automatically based on predefined rules
    2. Manually by an authorized user
    3. Semi-automatically: options are reduced by applying some predefined rules; user can select among the remaining options
  2. What object can be selected?
    1. Atomic activity
    2. Sub process
  3. When does late selection take place?
    1. Before the placeholder activity is enabled
    2. When enabling the placeholder activity

PP1

Implementation

By selecting the respective sub process or activity program, a reference to it is dynamically set and the sub-process or activity program is invoked.

Related Patterns

Late Modeling of Process Fragments (PP2)

Animation

View Animation

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