Timer

Last modified: September 26, 2024

Introduction

Timer allows you to configure a certain duration or a specific date and time in a workflow.

It can be used in the following two ways:

  • Timer can be used as a standalone activity on a workflow path. It suspends the workflow path for a configurable duration or until a set date and time. For example, when a new salary legislation is about to take effect, a timer can be set until the date of effect to actually adjust the values in the system.

    Standalone Timer activity

  • Timer can also be attached to another workflow activity as a Boundary Event (in Studio Pro 10.15.0 and above):

    Timer boundary event

Properties

Timer properties consist of the following sections:

General Section

The Caption describes what happens in this element. It is displayed under the workflow element to make the Timer easier to read and understand without the need to add annotations.

Timer Section

The Timer property can be configured in two ways: you can set a certain duration or a date and time with an expression. When the workflow path reaches the timer, the configured duration or date and time will be scheduled to take effect.

The Timer properties are described in the table below:

Type Description
Duration You can set a certain duration for the timer. With the Continue after setting, you can indicate the number of seconds, minutes, hours, days, weeks or months the timer’s duration is. Possible values for the setting are:
  • Seconds
  • Minutes
  • Hours
  • Days
  • Weeks
  • Months
Expression You can set a certain date and time for the timer by writing an expression via the Continue at setting.

For example, you can write addDays([%CurrentDateTime%], 1) to set tomorrow as the due date and time. To set a static date and time, you can use the expression parseDateTimeUTC('2023-12-10T17:12:00.000', 'yyyy-MM-dd''T''HH:mm:ss.SSS').

You can also create a more complex timer. For example, you can set a timer based on a Boolean value (in this example, isVIPUser) from the provided workflow context entity: if $WorkflowContext/isVIPUser then addDays([%CurrentDateTime%], 2) else addWeeks([%CurrentDateTime%], 2]).

For more information on available expressions in Mendix, see Expressions.

Common Section

Name is the internal name of the Timer. When referring to the activity in an application, you will use this name. It must be unique within the workflow, but you can have two Timer activities with the same name in different workflows.

Timer Expiration

When a Timer expires, it behaves differently depending on the state of the workflow:

  • When a timer is set on an in-progress workflow, the workflow continues when the timer expires.

  • When a time is set on a paused workflow and when the timer expires, the workflow only continues after the workflow is in progress again.

Specific Workflow State Cases

The following cases do not trigger a continuation of the workflow path when timer expires.

  • Expiration in a workflow that is aborted.
  • Expiration in a workflow that is incompatible - After the workflow resumes, the workflow path continues normally.
  • Expiration in a workflow that is jumped from the timer to a different activity.
  • Expiration in a workflow that is completed - This can only occur when Timer is used as a Boundary Event.
  • A workflow is restarted and a previous timer was still scheduled.

Workflow Incompatibility

When a Timer activity is added to the workflow definition and the application is redeployed, a validation on already running workflow instances is performed. When the Timer activity has been added before the currently in-progress activity, the workflow becomes incompatible. The conflict/incompatibility validation is analogous to other activities added before an in-progress activity. For more information, see Workflow Versioning and Conflict Mitigation.

When a Timer activity is removed from the workflow definition and the application is redeployed, on initiation of the application, it validates if there are any running timers (that is, active timers that are initiated but have not reached their defined date and time). In this case, the workflow becomes incompatible and a warning log is created. For information on how to resolve a conflict when an activity is removed, see Workflow Versioning and Conflict Mitigation.

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