vertx-scheduler's Introduction

vertx-scheduler

A module to implement scheduling on top of Vertx timers.

Initially this includes a weekly schedule with configurable behavior on DST changes.

Installation

...
dependencies {
  ...
  compile "com.sendgrid.labs:vertx-scheduler:$schedulerVersion"
}

repositories {
  mavenCentral()
}
...

Use

Create a new scheduler

Scheduler scheduler = Scheduler.create(vertx);

Create a time of week

// Tuesday at 2:30 AM UTC
TimeOfWeek time1 = TimeOfWeek.create(Day.TUE, 2, 30, 0, 0);

// Tuesday at 2:30 AM localtime
TimeOfWeek time2 = TimeOfWeek.create(TimeZone.getTimeZone("America/New_York"), Day.TUE, 2, 30, 0, 0);

// Sunday at 01:01 AM UTC
TimeOfWeek time3 = TimeOfWeek.create(60*60*1000 + 60*1000);

// Sunday at 01:01 AM localtime
TimeOfWeek time4 = TimeOfWeek.create(TimeZone.getTimeZone("America/New_York"), 60*60*1000 + 60*1000);

Set a one shot timer on next occurrence of time

Timer timer1 = scheduler.setTimer(time1, new Handler<Timer>() {
    public void handle(Timer t) {
        // ...
    }
});

Set a periodic timer to fire on every occurrence of time

Timer timer2 = scheduler.setPeriodic(time2, new Handler<Timer>() {
    public void handle(Timer t) {
        // ...
    }
});

Cancel a timer

scheduler.cancelTimer(timer1);

Daylight Saving Time

Behavior on DST changes is configurable. Default is to skip when time changes ahead and to run both when time changes back.

TimeOfWeek time1 = TimeOfWeek.create(TimeZone.getTime("America/New_York", Day.TUE, 2, 30, 0, 0, DstAheadBehavior.DST_AHEAD_SKIP, DstBackBehavior.DST_BACK_BOTH_HOURS);

Time change ahead

The scheduler can either skip any events during the missing hour (DST_AHEAD_SKIP), or run them on the next hour (DST_AHEAD_NEXT_HOUR).

Time change back

The scheduler can callback on the first occurrence of the duplicated hour (DST_BACK_FIRST_HOUR), just the second (DST_BACK_SECOND_HOUR), or both (DST_BACK_BOTH_HOURS).