Unit Triggers & Events
- Thomas Staiger
As already mentioned in the chapter → onCore Execution Model the execution model of onCore is based on a sequential flow-of-control-model.
Triggers and Events must be used to initiate the execution of Units. Therefore a Unit where the Execute Trigger is not wired will not do anything.
Unit Triggers
Triggers are represented by grey, green and red triangles. They cannot be wired to anything else than their own kind.
| Trigger Type | Trigger Representation | Trigger Description |
|---|---|---|
| Execute Trigger |
| This trigger gets fired by the execution flow and the Unit will be called to execute. |
| Success Trigger |
| Upon completion, this trigger will be automatically fired and the next Unit, which has its Execute Trigger wired to this Complete Trigger, will be executed next. |
| Fail Trigger |
| If something goes wrong while a Unit is being executed, the Fail Trigger will be fired instead of the Success Trigger. |
Units usually have two output Triggers (Success and Fail), which can be used to branch to individual flows. These triggers precisely define the execution flow of the Workflow. As a consequence to the strictly controlled execution flow, it is not possible to wire a Trigger to multiple other Triggers. If this is required please use the appropriate Units, such as Multi Trigger, Branch and Trigger Join.
Event Units
| Event Units are used to trigger execution of an entire Workflow, or just a subset of a Workflow, or a Subworkflow. This is a very powerful concept, allowing Workflows to be triggered from any Workflow condition, but also – for example – from network events. The simplest example is the Trigger on Start event. |
| Event Type | Event Description |
|---|---|
| Trigger on Start | Sends a Trigger when the Workflow is started. |
| Trigger on Stop | Sends a Trigger when the Workflow is stopped. |
| UI Trigger | Sends a Trigger when the Trigger Button has been clicked. |
| Trigger Tick | Sends a trigger based on a time interval. If the old-style method of regular execution is required, this Unit can be used. |
The UI Trigger Unit is very helpful to quickly test a Workflow or a certain part of a Workflow.