Submits a periodic action that becomes enabled first after the
given initial delay, and subsequently with the given delay
between the termination of one execution and the commencement of
the next.
<p>The sequence of task executions continues indefinitely until
one of the following exceptional completions occur:
<ul>
<li>The task is {@linkplain Future#cancel explicitly cancelled}
via the returned future.
<li>The executor terminates, also resulting in task cancellation.
<li>An execution of the task throws an exception. In this case
calling {@link Future#get() get} on the returned future will throw
{@link ExecutionException}, holding the exception as its cause.
</ul>
Subsequent executions are suppressed. Subsequent calls to
{@link Future#isDone isDone()} on the returned future will
return {@code true}.
@param command the task to execute
@param initialDelay the time to delay first execution
@param delay the delay between the termination of one
execution and the commencement of the next
@param unit the time unit of the initialDelay and delay parameters
@return a ScheduledFuture representing pending completion of
the series of repeated tasks. The future's {@link
Future#get() get()} method will never return normally,
and will throw an exception upon task cancellation or
abnormal termination of a task execution.
@throws RejectedExecutionException if the task cannot be
scheduled for execution
@throws NullPointerException if command or unit is null
@throws IllegalArgumentException if delay less than or equal to zero
Submits a periodic action that becomes enabled first after the given initial delay, and subsequently with the given delay between the termination of one execution and the commencement of the next.
<p>The sequence of task executions continues indefinitely until one of the following exceptional completions occur: <ul> <li>The task is {@linkplain Future#cancel explicitly cancelled} via the returned future. <li>The executor terminates, also resulting in task cancellation. <li>An execution of the task throws an exception. In this case calling {@link Future#get() get} on the returned future will throw {@link ExecutionException}, holding the exception as its cause. </ul> Subsequent executions are suppressed. Subsequent calls to {@link Future#isDone isDone()} on the returned future will return {@code true}.
@param command the task to execute @param initialDelay the time to delay first execution @param delay the delay between the termination of one execution and the commencement of the next @param unit the time unit of the initialDelay and delay parameters @return a ScheduledFuture representing pending completion of the series of repeated tasks. The future's {@link Future#get() get()} method will never return normally, and will throw an exception upon task cancellation or abnormal termination of a task execution. @throws RejectedExecutionException if the task cannot be scheduled for execution @throws NullPointerException if command or unit is null @throws IllegalArgumentException if delay less than or equal to zero