Query pattern
The following pattern table explains the features of the query pattern:
|
Signature |
Query Pattern/Query Instance Pattern |
|
Classification |
Correlation Pattern |
|
Intent |
To query an already executing process instance. |
|
Motivation |
Based on the process status or business logic, there are requirements to query an already running process for varied information. |
|
Applicability |
When a query event occurs, the regular flow of the process will be interrupted and the query event subprocess will execute in parallel with the main BPMN process. |
|
Implementation |
We can use the event subprocess to query an existing process without even interrupting the main process, and both the main process and the query event subprocess will run in parallel. A new token is created for the query event subprocess. |
|
Known issues |
Making certain that the request to query a process instance must result from the process instance that it is meant for. |
|
Known solution |
Correlation. |
Event subprocesses...
