Moduliths Moments

Moments is an implementation of the Passage of Time Event idea, originally presented by Mathias Verraes. It enables Spring Boot applications to consume the following events to attach business logic to them:

• DayHasPassed - signals the end of a day

• WeekHasPassed - signals the end of a week

• MonthHasPassed - signals the end of a month

• QuarterHasPassed - signals the end of a quarter

• YearHasPassed - signals the end of a year

This allows event listeners to be registered that react on the publication of such events. They allow to decouple from the actual triggering mechanism (e.g. Spring’s built-in scheduling) and can thus be tested more easily.

How to use Moments?

Moments will auto-activate in a Spring Boot application if you put it on the classpath of your application.

<dependency>
  <groupId>org.springframework.modulith</groupId>
  <artifactId>spring-modulith-moments</artifactId>
  <version>…</version>
</dependency>

What does Moments enable?

The Moments module enables scheduling for the application it is applied to. It registers a bean of type Moments that takes care of publishing the above mentioned events. By setting moduliths.moments.enable-time-machine you can also rather expose a bean of type TimeMachine (which extends Moments), which exposes a ….shift(Duration) method which allows to move what constitutes "now" by the given Duration. Moving time forward will cause all events published that would occur during the delta.

How to disable Moments?

If you don’t control the classpath of the application you run, you can still disable Moments by setting the moduliths.moments.enabled property to false.

Customization options

Moments works with Java’s standard Clock abstraction to determine the current time. By default, Clock.standardUTC() is used. To use a different clock, just register a Spring Bean of type Clock. Moments will pick it up automatically.

Moments configuration properties

Moments exposes configuration properties to tweak its behavior under the moduliths.moments namespace.

Property	Default value	Description
enabled	true	Whether to enable Moments in the first place.
enable-time-machine	false	Set to true to expose TimeMachine instead of Moments to publicly expose methods to shift time.
granularity	hours	At which granularity to publish events. Switch to days if you want to disable the distribution of HourHasPassed events.
locale	Locale.default()	The Locale to determine the start date of the week for WeekHasPassed events.
quarter-start-month	January	The month in which the first quarter starts. Customize via the month’s name you like to start the quarters at (e.g. February).
zone-id	UTC	The time zone to determine the dates and times attached to the events published. Use standardized region time zone descriptors (e.g. Europe/Berlin) to customize