/**@class java.util.concurrent.ScheduledExecutorService implements java.util.concurrent.ExecutorService An {@link java.util.concurrent.ExecutorService} that can schedule commands to run after a given delay, or to execute periodically. <p>The {@code schedule} methods create tasks with various delays and return a task object that can be used to cancel or check execution. The {@code scheduleAtFixedRate} and {@code scheduleWithFixedDelay} methods create and execute tasks that run periodically until cancelled. <p>Commands submitted using the {@link java.util.concurrent.Executor#execute(Runnable)} and {@link java.util.concurrent.ExecutorService} {@code submit} methods are scheduled with a requested delay of zero. Zero and negative delays (but not periods) are also allowed in {@code schedule} methods, and are treated as requests for immediate execution. <p>All {@code schedule} methods accept <em>relative</em> delays and periods as arguments, not absolute times or dates. It is a simple matter to transform an absolute time represented as a {@link java.util.Date} to the required form. For example, to schedule at a certain future {@code date}, you can use: {@code schedule(task, date.getTime() - System.currentTimeMillis(), TimeUnit.MILLISECONDS)}. Beware however that expiration of a relative delay need not coincide with the current {@code Date} at which the task is enabled due to network time synchronization protocols, clock drift, or other factors. <p>The {@link java.util.concurrent.Executors} class provides convenient factory methods for the ScheduledExecutorService implementations provided in this package. <h3>Usage Example</h3> Here is a class with a method that sets up a ScheduledExecutorService to beep every ten seconds for an hour: <pre> {@code import static java.util.concurrent.TimeUnit.*; class BeeperControl { private final ScheduledExecutorService scheduler = Executors.newScheduledThreadPool(1); public void beepForAnHour() { final Runnable beeper = new Runnable() { public void run() { System.out.println("beep"); } }; final ScheduledFuture<?> beeperHandle = scheduler.scheduleAtFixedRate(beeper, 10, 10, SECONDS); scheduler.schedule(new Runnable() { public void run() { beeperHandle.cancel(true); } }, 60 * 60, SECONDS); } }}</pre> @since 1.5 @author Doug Lea */ var ScheduledExecutorService = { /**Creates and executes a one-shot action that becomes enabled after the given delay. @param {Object {Runnable}} command the task to execute @param {Number} delay the time from now to delay execution @param {Object {TimeUnit}} unit the time unit of the delay parameter @return {Object {java.util.concurrent.ScheduledFuture}} a ScheduledFuture representing pending completion of the task and whose {@code get()} method will return {@code null} upon completion @throws RejectedExecutionException if the task cannot be scheduled for execution @throws NullPointerException if command is null */ schedule : function( ) {}, /**Creates and executes a ScheduledFuture that becomes enabled after the given delay. @param {Object {java.util.concurrent.Callable}} callable the function to execute @param {Number} delay the time from now to delay execution @param {Object {TimeUnit}} unit the time unit of the delay parameter @param <V> the type of the callable's result @return {Object {java.util.concurrent.ScheduledFuture}} a ScheduledFuture that can be used to extract result or cancel @throws RejectedExecutionException if the task cannot be scheduled for execution @throws NullPointerException if callable is null */ schedule : function( ) {}, /**Creates and executes a periodic action that becomes enabled first after the given initial delay, and subsequently with the given period; that is, executions will commence after {@code initialDelay}, then {@code initialDelay + period}, then {@code initialDelay + 2 * period}, and so on. <p>The sequence of task executions continues indefinitely until one of the following exceptional completions occur: <ul> <li>The task is {@linkplain java.util.concurrent.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 java.util.concurrent.Future#get() get} on the returned future will throw {@link java.util.concurrent.ExecutionException}. </ul> Subsequent executions are suppressed. Subsequent calls to {@link java.util.concurrent.Future#isDone isDone()} on the returned future will return {@code true}. <p>If any execution of this task takes longer than its period, then subsequent executions may start late, but will not concurrently execute. @param {Object {Runnable}} command the task to execute @param {Number} initialDelay the time to delay first execution @param {Number} period the period between successive executions @param {Object {TimeUnit}} unit the time unit of the initialDelay and period parameters @return {Object {java.util.concurrent.ScheduledFuture}} 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 is null @throws IllegalArgumentException if period less than or equal to zero */ scheduleAtFixedRate : function( ) {}, /**Creates and executes 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 java.util.concurrent.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 java.util.concurrent.Future#get() get} on the returned future will throw {@link java.util.concurrent.ExecutionException}. </ul> Subsequent executions are suppressed. Subsequent calls to {@link java.util.concurrent.Future#isDone isDone()} on the returned future will return {@code true}. @param {Object {Runnable}} command the task to execute @param {Number} initialDelay the time to delay first execution @param {Number} delay the delay between the termination of one execution and the commencement of the next @param {Object {TimeUnit}} unit the time unit of the initialDelay and delay parameters @return {Object {java.util.concurrent.ScheduledFuture}} 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 is null @throws IllegalArgumentException if delay less than or equal to zero */ scheduleWithFixedDelay : function( ) {}, };