Workflow event-specific functions
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Summary of Workflow Event-Specific Functions
This guide details the functions related to workflow events in ServiceNow, focusing on how they enable workflow management within the system. These functions allow users to register, unregister, and trigger events within workflows, facilitating dynamic interactions between workflow activities.
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Key Features
- registerForEvent(eventName): Registers an event string in the wfexecuting.registeredevents field, allowing activities to listen for specific events.
- unRegisterForEvent(eventName): Removes a registered event from wfexecuting.registeredevents, effectively stopping the listening for that event.
- fireEvent(eventName): Triggers all currently executing records that have registered for the specified event.
- fireEvent(eventRecord, eventName): Sends an event to a specific executing activity record, requiring an associated event handler.
- fireEvent(eventRecordSysId, eventName): Similar to the previous function but accepts a sysid for the executing record.
- fireEvent(eventRecordSysId, eventName, optionalJSONObject): Sends an event along with optional JSON data to a specific executing activity record.
- broadcastEvent(contextId, eventName): Sends an event to all running executing records within a specified context.
- broadcastEvent(eventName): Similar to the previous broadcast function but targets only the current context.
Key Outcomes
Utilizing these functions allows ServiceNow customers to create responsive and interactive workflows that can adapt to events in real-time. By leveraging event registration and triggering capabilities, customers can enhance their workflows' functionality, ensuring they react appropriately to various conditions and user interactions.
There are several functions that relate specifically to workflow events.
| Function | Description | Purpose | Use | Thread | Source |
|---|---|---|---|---|---|
| registerForEvent (eventName) | Function in the workflow environment that writes events represented as strings
to the wf_executing.registered_events field. |
The workflow events are just strings. When an activity that has registered for
an event executes, a comma delimited set of events is stored with the Workflow
Executing Activity [wf_executing] record. When the event is triggered in the
workflow context, the wf_executing table looks for all executing records that
contain the string that represents the event in the
wf_executing.registered_events field |
The global variable workflow that is available to all Workflow Activity
[wf_activity] records is the source of the call. For example, from inside a
Run Script activity, a designer can write:
workflow.registerForEvent('myEventName'); |
Current thread, current mutex | Global variable workflow |
| unRegisterForEvent (eventName) | Function in the workflow environment that removes a string value representing
an event that has been written to the
wf_executing.registered_events field. |
The workflow events are just strings that are written to the
wf_executing.registered_events field. When an activity
unRegisters for an event, the comma delimited set of events stored with the Workflow
Executing Activity [wf_executing] record is searched, and if that string is found,
it is removed. |
The global variable workflow that is available to all Workflow Activity
[wf_activity] records is the source of the call. For example, from inside a
Run Script activity, a designer can write:
workflow.unRegisterForEvent('myEventName'); |
Current thread, current mutex | Global variable workflow |
| fireEvent (eventName) | Function in the workflow environment that examines the contents of the
wf_executing.registered_events field, comparing its contents to
the eventName passed in. |
The workflow events are just strings that are written to the
wf_executing.registered_events field. When
fireEvent(eventName) is called by a workflow activity, the
workflow engine queues up any executing records that contain the string in the
registered field. |
The global variable workflow that is available to all Workflow Activity
[wf_activity] records is the source of the call. For example, from inside a
Run Script activity, a designer can write:
workflow.fireEvent('myEventName'); |
Current thread, current mutex | Global variable workflow |
| fireEvent (eventRecord, eventName) | Function in the workflow environment that sends an event to a specific Workflow
Executing Activity [wf_executing] record. The eventRecord is a
GlideRecord of the type wf_executing. |
This event call expects an onMyEvent event handler in the activity represented in the event record (Workflow Executing Activity [wf_executing] table). When fireEvent(eventRecord, eventName) is called by a workflow activity, the workflow engine queues up the specific executing record with that event and passes the event into the activity definition for the on<eventName> handler to manage. This event is queued up in its own mutex, so the current queue completes before this event is processed. | The workflow script include contains the call for this. For example, from
inside a Run Script activity, a designer can write:
var w = new Workflow(); w.fireEvent(executing,
eventName); |
Current thread, current mutex | Workflow script include |
| fireEvent (eventRecordSysId, eventName) | Function in the workflow environment that sends an event to a specific Workflow
Executing Activity [wf_executing] record. The eventRecordSysId is
the sys_id of a GlideRecord of the type wf_executing. |
This is the same as the fireEvent above, except that it accepts an ID and returns the Workflow Executing Activity [wf_executing] record. | The Workflow script include contains the call for this. For
example, from inside a Run Script activity, a designer can
write: var w = new Workflow(); w.fireEvent(executing,
eventName); |
Current thread, current mutex | Workflow script include |
| fireEvent (eventRecordSysId, eventName, optionalJSONObject) | Function in the workflow environment that sends an event to a specific Workflow
Executing Activity [wf_executing] record. The eventRecordSysId is
the sys_id of a GlideRecord of the type wf_executing. |
This is the same as the fireEvent above, except that it accepts a JSON object as a third parameter. This object can specify any data expressible as JSON. You can also specify additional functionality when creating a workflow activity. | The Workflow script include contains the call for this. For
example, from inside a Run Script activity, a designer can
write: var w = new Workflow(); w.fireEvent(executing, eventName,
JSONObject); |
Current thread, current mutex | Workflow script include |
| broadcastEvent (contextId, eventName) | Function in the workflow environment that sends an event to all currently running Workflow Executing Activity [wf_executing] records in a specified context, regardless of their state. | This is the same as the fireEvent above, except that it accepts an ID and returns the Workflow Executing Activity [wf_executing] record. | The Workflow script include contains the call for this. For
example, from inside a Run Script activity, a designer can
write: var w = new Workflow(); w.broadcastEvent(contextId,
eventName); |
Current thread, current mutex | Workflow script include |
| broadcastEvent (eventName) | Function in the workflow environment that sends an event to all currently running Workflow Executing Activity [wf_executing] records in the current context, regardless of their state. | This should not be confused with broadcastEvent above. This event is only available to current Workflow Executing Activity [wf_executing] records. | This is available only through the global workflow variable of the current
context. The following is an example of its use from within an activity definition's
script: workflow.broadcastEvent(eventName) |
Current thread, current mutex | Global variable workflow |