Event State

Parameter	Description	Type	Required
name	Unique State name	string	yes
type	State type	string	yes
exclusive	If true, consuming one of the defined events causes its associated actions to be performed. If false, all of the defined events must be consumed in order for actions to be performed. Default is true	boolean	no
onEvents	Define the events to be consumed and optional actions to be performed	array	yes
timeouts	State specific timeout settings	object	no
stateDataFilter	State data filter definition	object	no
transition	Next transition of the workflow after all the actions have been performed	string or object	yes (if end is not defined)
onErrors	States error handling definitions	array	no
end	Is this state an end state	boolean or object	yes (if transition is not defined)
compensatedBy	Unique name of a workflow state which is responsible for compensation of this state	string	no
metadata	Metadata information	object	no

Example:

JSON

YAML

{ "name": "monitor-vitals", "type": "event", "exclusive": true, "onEvents": [{ "eventRefs": ["high-body-temperature"], "actions": [{ "functionRef": { "refName": "send-tylenol-order", "arguments": { "patientid": "${ .patientId }" } } }] }, { "eventRefs": ["high-blood-pressure"], "actions": [{ "functionRef": { "refName": "call-nurse", "arguments": { "patientid": "${ .patientId }" } } }] }, { "eventRefs": ["high-respiration-rate"], "actions": [{ "functionRef": { "refName": "call-pulmonologist", "arguments": { "patientid": "${ .patientId }" } } }] } ], "end": { "terminate": true } }

name: monitor-vitals type: event exclusive: true onEvents: - eventRefs: - high-body-temperature actions: - functionRef: refName: send-tylenol-order arguments: patientid: "${ .patientId }" - eventRefs: - high-blood-pressure actions: - functionRef: refName: call-nurse arguments: patientid: "${ .patientId }" - eventRefs: - high-respiration-rate actions: - functionRef: refName: call-pulmonologist arguments: patientid: "${ .patientId }" end: terminate: true

Event states await one or more events and perform actions when they are received. If defined as the workflow starting state, the event state definition controls when the workflow instances should be created.

The exclusive property determines if the state should wait for any of the defined events in the onEvents array, or if all defined events must be present for their associated actions to be performed.

Following two figures illustrate the exclusive property:

If the Event state in this case is a workflow starting state, the occurrence of any of the defined events would start a new workflow instance.

If the Event state in this case is a workflow starting state, the occurrence of all defined events would start a new workflow instance.

In order to consider only events that are related to each other, we need to set the correlation property in the workflow events definitions. This allows us to set up event correlation rules against the events extension context attributes.

If the Event state is not a workflow starting state, the timeout property can be used to define the time duration from the invocation of the event state. If the defined event, or events have not been received during this time, the state should transition to the next state or can end the workflow execution (if it is an end state).

The timeouts property can be used to define state specific timeout settings. Event states can define the stateExecTimeout, actionExecTimeout, and eventTimeout properties. For more information about Event state specific event timeout settings reference this section. For more information about workflow timeouts reference the Workflow Timeouts section.

Note that transition and end properties are mutually exclusive, meaning that you cannot define both of them at the same time.