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Signal events

Signal events are events which reference a signal. Broadcasting a signal will trigger all signal events matching the name of the broadcasted signal.

Signal start events​

Process with a top-level signal start event

Signal start event can be used to start process instances. Deploying processes with a signal start event enables creating multiple process instances by performing a single broadcast.

Broadcasting a signal will iterate over the available subscriptions. If the name of the broadcasted signal matches the name of the signal start event, the process instance is created.

Signal subscriptions only exist for the latest version of a process definition. Deploying a new version of the same process (based on the BPMN process id) will delete the old signal subscription. A new subscription is opened for the new deployed process definition.

Variable mappings​

When broadcasting a signal you can pass along variables. By default, all signal variables are merged into the process instance. This behavior can be customized by defining an output mapping at the signal catch event.

For more information about variable scopes, visit the documentation about variable scopes.

Additional resources​

XML representation​

A signal start event with signal definition:

<bpmn:startEvent id="startEventId">
    <bpmn:signalEventDefinition id="signalEventDefinitionId" signalRef="signalId" />
</bpmn:startEvent>

<bpmn:signal id="signalId" name="signal" />