com.hazelcast.spi

Interface TaskScheduler

All Superinterfaces:

Executor

All Known Subinterfaces:

ClientExecutionService

All Known Implementing Classes:

ClientExecutionServiceImpl, DelegatingTaskScheduler

public interface TaskScheduler
extends Executor

ExecutorService can schedule a command to run after a given delay or execute periodically. The scheduleWithRepetition(Runnable, long, long, TimeUnit) has similar semantic to ScheduledExecutorService.scheduleAtFixedRate(Runnable, long, long, TimeUnit). It guarantees a task won't be executed by multiple threads concurrently. The difference is that this service will skip a scheduled execution if another thread is still running the same task, instead of postponing its execution. To emphasize this difference the method is called scheduleWithRepetition instead of scheduleAtFixedRate The other difference is this service does not offer an equivalent of ScheduledExecutorService.scheduleWithFixedDelay(Runnable, long, long, TimeUnit)

Method Summary

Modifier and Type	Method and Description
<V> ScheduledFuture<Future<V>>	schedule(Callable<V> command, long delay, TimeUnit unit) Creates and executes a one-shot action that becomes enabled after the given delay.
ScheduledFuture<?>	schedule(Runnable command, long delay, TimeUnit unit) Creates and executes a one-shot action that becomes enabled after the given delay.
ScheduledFuture<?>	scheduleWithRepetition(Runnable command, long initialDelay, long period, TimeUnit unit) Creates and executes a periodic action that becomes enabled first after the given initial delay, and subsequently with the given period.

Methods inherited from interface java.util.concurrent.Executor

execute

Method Detail

schedule

ScheduledFuture<?> schedule(Runnable command,
                            long delay,
                            TimeUnit unit)

Creates and executes a one-shot action that becomes enabled after the given delay.

Parameters:

command - the task to execute

delay - the time from now to delay execution

unit - the time unit of the delay parameter

Returns:

a ScheduledFuture representing pending completion of the task and whose get() method will return null upon completion

Throws:

RejectedExecutionException - if the task cannot be scheduled for execution

NullPointerException - if command is null

schedule

<V> ScheduledFuture<Future<V>> schedule(Callable<V> command,
                                        long delay,
                                        TimeUnit unit)

Creates and executes a one-shot action that becomes enabled after the given delay.

Parameters:

command - the task to execute

delay - the time from now to delay execution

unit - the time unit of the delay parameter

Returns:

a ScheduledFuture representing pending completion of the task and whose get() method will return <V> upon completion

Throws:

RejectedExecutionException - if the task cannot be scheduled for execution

NullPointerException - if command is null

scheduleWithRepetition

ScheduledFuture<?> scheduleWithRepetition(Runnable command,
                                          long initialDelay,
                                          long period,
                                          TimeUnit unit)

Creates and executes a periodic action that becomes enabled first after the given initial delay, and subsequently with the given period. Executions will commence after initialDelay then initialDelay+period, then initialDelay + 2 * period, and so on. If any execution of this task takes longer than its period, then subsequent execution will be skipped.

Parameters:

command - the task to execute

initialDelay - the time to delay first execution

period - the period between successive executions

unit - the time unit of the initialDelay and period parameters

Returns:

a ScheduledFuture representing pending completion of the task, and whose get() method will throw an exception upon cancellation

Throws:

RejectedExecutionException - if the task cannot be scheduled for execution

NullPointerException - if command is null

IllegalArgumentException - if period is less than or equal to zero