Wednesday, 12 June 2013 16:03

Pattern AP6: EXTRACT Sub Process

The pattern Extract Sub Process (AP6) allows users to extract an existing process fragment from a process schema and to encapsulate it in a separate sub process schema. This pattern can be used to add a hierarchical level to simplify a process schema or to hide information from process participants. If no direct support for pattern AP6 is provided a possible workaround will look as follows: The new schema representing the extracted sub process has to be created manually. Next, the respective process fragment must be copied to the new process schema and be removed from the original one. In addition, an activity referencing the newly implemented sub process must be added to the original schema, and required input and output parameters must be manually mapped to the sub process (not considered in detail here). The implementation of pattern AP6 can be based on
graph aggregation techniques.


From a given process schema S a process fragment is extracted and replaced by a corresponding sub process.


A dynamically evolving engineering process has become too large. To reduce complexity the process owner extracts activities related to the engineering of a particular component and encapsulates them in a separate sub process.


Large process schema. If a process schema becomes too large, this pattern will allow for its hierarchical (re-)structuring. This simplifies maintenance, increases comprehensibility, and fosters the reuse of process fragments.

Duplication across process schemes. A particular process fragment appears in multiple process schemes. If the respective fragment has to be changed, this change will have to be conducted repetitively for all these schemes. This, in turn, can lead to inconsistencies. By encapsulatingthe fragment in one sub process, maintenance costs can be reduced (see figure below).



For implementing pattern AP6 graph aggregation techniques can be used. When considering data aspects as well, variables which constitute input / output for the selected process fragment have to be determined and must be considered as input / output for the created sub process.

Related Patterns

Inline Sub Process (AP7)


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