Work with Intermediate Events

Unlike start and stop events, intermediate events occur during the flow of your business process. You can use them to control the flow and behavior of your business process.

There are two types of intermediate events:

• Normal flow events: These events occur within the typical flow of your business process.

• Boundary events: These events trigger an interruption with your business process.

  Boundary events are associated with flow elements and can be configured to interrupt their usual behavior. They behave similar to sequence flows in that they’re used to determine the path a process takes between flow elements.

  Boundary events can be divided into two types: interrupting and non-interrupting.

About the Timer Catch Event

Timer catch events lets you control the flow of your business process using a time condition.

Possible uses of the time catch event include:

• Creating a delay before running an activity

• Configuring a deadline for an activity

• Configuring a deadline for a process

• Triggering additional activities after an elapsed time

You can use timer events as boundary events on an activity. Timer events can be defined as either interrupting or non-interrupting boundary events.

When an interrupting timer event fires, the token leaves the main process flow to follow the process flow the timer event defines. The process flow that an interrupting timer event defines can return directly to the main process flow.

When a non interrupting event fires, a copy of the token is created and passes through the process flow the timer event defines. The process flow that a non-interrupting event defines can’t return to the main process flow.

About the Error Boundary Event

Error boundary events are intermediate events used to handle an error that occurs within your process flow.

Error boundary events can be attached to the following flow elements:

• Service tasks

• Call activities

• Human tasks

• Send tasks

• Receive tasks

• Script tasks

• Decision tasks

• Subprocesses

Error boundary events are always interrupting, meaning that they interrupt the usual flow of a business process.

The following image shows the default notation for the error boundary event attached to a service task.

When a service or process fails with an error, the error boundary event is triggered. This causes the process flow to follow the path of the outgoing sequence flow of the error boundary event.

You can use this flow to define how to handle the error. This is handled in two ways:

• The process flow returns to the main process flow.

  Any work that must be performed is handled within the error process flow before returning to the main flow.

  Note:

  If the boundary event is non-interrupting, the boundary flow can’t return to the main process flow.

• The process flow continues to an end event.

  The process is stopped immediately. Process control is returned to the service or process that initiated the process.