Spring scheduling task - run only once

Dead man's solution:

@Scheduled(initialDelay = 1000 * 30, fixedDelay=Long.MAX_VALUE)

You will be dead before it fires again.

You can use one of Spring's TaskScheduler's implementations. I provided an example below with one which does not require too much configuration (ConcurrentTaskScheduler that wraps a single-threaded scheduled executor).

The simplest method is the one named schedule that takes a Runnable and Date only. That will cause the task to run once after thespecified time. All of the other methods are capable of scheduling tasks to run repeatedly.

Read more on task execution & scheduling

Simple working example:

private TaskScheduler scheduler;Runnable exampleRunnable = new Runnable(){    @Override    public void run() {        System.out.println("Works");    }};@Asyncpublic void executeTaskT() {    ScheduledExecutorService localExecutor = Executors.newSingleThreadScheduledExecutor();    scheduler = new ConcurrentTaskScheduler(localExecutor);    scheduler.schedule(exampleRunnable,            new Date(1432152000000L));//today at 8 pm UTC - replace it with any timestamp in miliseconds to text}...executeTaskT() //call it somewhere after the spring application has been configured

Note:

To enable support for @Scheduled and @Async annotations add @EnableScheduling and @EnableAsync to one of your @Configuration classes

Update - cancelling the scheduled task

TaskScheduler's schedule method returns a ScheduledFuture which is a delayed result-bearing action that can be cancelled.

So in order to cancel it, you need to keep a handle to the scheduled task (i.e. keep the ScheduledFuture return object).

Changes to the code above for cancelling the task :

1. Declare the ScheduledFuture outside your executeTaskT method.

    private ScheduledFuture scheduledFuture;

2. Modify your call to schedule to keep the return object as such:

    scheduledFuture = scheduler.schedule(exampleRunnable,                    new Date(1432152000000L));

3. Call cancel on the scheduledFuture object somewhere in your code

    boolean mayInterruptIfRunning = true;    scheduledFuture.cancel(mayInterruptIfRunning);

You can extend PeriodicTrigger as follows - it checks the lastCompletionTime: it will be null if the task has never run before. You can try variation of this if you want to run the task just once at some given time.

class RunOnceTrigger extends PeriodicTrigger {    public RunOnceTrigger(long period) {        super(period);        setInitialDelay(period);    }    @Override    public Date nextExecutionTime(TriggerContext triggerContext) {        if(triggerContext.lastCompletionTime() == null) {   // hasn't executed yet            return super.nextExecutionTime(triggerContext);        }        return null;    }}