Scheduler

Returns the clock drift tolerance in nanoseconds.

Related system property: rx2.scheduler.drift-tolerance in minutes

Retrieves or creates a new Scheduler.Worker that represents serial execution of actions.

When work is completed it should be unsubscribed using dispose().

Work on a Scheduler.Worker is guaranteed to be sequential.

Returns the 'current time' of the Scheduler in the specified time unit.

Schedules the given task on this scheduler non-delayed execution.

This method is safe to be called from multiple threads but there are no ordering guarantees between tasks.

Schedules the execution of the given task with the given delay amount.

This method is safe to be called from multiple threads but there are no ordering guarantees between tasks.

Schedules a periodic execution of the given task with the given initial delay and period.

This method is safe to be called from multiple threads but there are no ordering guarantees between tasks.

The periodic execution is at a fixed rate, that is, the first execution will be after the initial delay, the second after initialDelay + period, the third after initialDelay + 2 * period, and so on.

Instructs the Scheduler instance to stop threads and stop accepting tasks on any outstanding Workers.

Implementations should make sure the call is idempotent and thread-safe.

Allows the Scheduler instance to start threads and accept tasks on them.

Implementations should make sure the call is idempotent and thread-safe.

Allows the use of operators for controlling the timing around when actions scheduled on workers are actually done. This makes it possible to layer additional behavior on this Scheduler. The only parameter is a function that flattens an Flowable of Flowable of Completables into just one Completable. There must be a chain of operators connecting the returned value to the source Flowable otherwise any work scheduled on the returned Scheduler will not be executed.

When createWorker() is invoked a Flowable of Completables is onNext'd to the combinator to be flattened. If the inner Flowable is not immediately subscribed to an calls to schedule(Runnable) are buffered. Once the Flowable is subscribed to actions are then onNext'd as Completables.

Finally the actions scheduled on the parent Scheduler when the inner most Completables are subscribed to.

When the Scheduler.Worker is unsubscribed the Completable emits an onComplete and triggers any behavior in the flattening operator. The Flowable and all Completables give to the flattening function never onError.

Limit the amount concurrency two at a time without creating a new fix size thread pool:

 Scheduler limitScheduler = Schedulers.computation().when(workers -> {
  // use merge max concurrent to limit the number of concurrent
  // callbacks two at a time
  return Completable.merge(Flowable.merge(workers), 2);
 });
 

This is a slightly different way to limit the concurrency but it has some interesting benefits and drawbacks to the method above. It works by limited the number of concurrent Scheduler.Workers rather than individual actions. Generally each Flowable uses its own Scheduler.Worker. This means that this will essentially limit the number of concurrent subscribes. The danger comes from using operators like zip(org.reactivestreams.Publisher, org.reactivestreams.Publisher, io.reactivex.functions.BiFunction) where subscribing to the first Flowable could deadlock the subscription to the second.

 Scheduler limitScheduler = Schedulers.computation().when(workers -> {
  // use merge max concurrent to limit the number of concurrent
  // Flowables two at a time
  return Completable.merge(Flowable.merge(workers, 2));
 });
 

 Scheduler slowScheduler = Schedulers.computation().when(workers -> {
  // use concatenate to make each worker happen one at a time.
  return Completable.concat(workers.map(actions -> {
      // delay the starting of the next worker by 1 second.
      return Completable.merge(actions.delaySubscription(1, TimeUnit.SECONDS));
  }));
 });
 

History: 2.0.1 - experimental