- /*
- * @(#)ScheduledExecutorService.java 1.2 04/04/14
- *
- * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
- * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
- */
-
- package java.util.concurrent;
- import java.util.concurrent.atomic.*;
- import java.util.*;
-
- /**
- * An {@link ExecutorService} that can schedule commands to run after a given
- * delay, or to execute periodically.
- *
- * <p> The <tt>schedule</tt> methods create tasks with various delays
- * and return a task object that can be used to cancel or check
- * execution. The <tt>scheduleAtFixedRate</tt> and
- * <tt>scheduleWithFixedDelay</tt> methods create and execute tasks
- * that run periodically until cancelled.
- *
- * <p> Commands submitted using the {@link Executor#execute} and
- * {@link ExecutorService} <tt>submit</tt> methods are scheduled with
- * a requested delay of zero. Zero and negative delays (but not
- * periods) are also allowed in <tt>schedule</tt> methods, and are
- * treated as requests for immediate execution.
- *
- * <p>All <tt>schedule</tt> 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 <tt>date</tt>, you can use: <tt>schedule(task,
- * date.getTime() - System.currentTimeMillis(),
- * TimeUnit.MILLISECONDS)</tt>. Beware however that expiration of a
- * relative delay need not coincide with the current <tt>Date</tt> at
- * which the task is enabled due to network time synchronization
- * protocols, clock drift, or other factors.
- *
- * The {@link 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>
- * 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
- */
- public interface ScheduledExecutorService extends ExecutorService {
-
- /**
- * Creates and executes a one-shot action that becomes enabled
- * after the given delay.
- * @param command the task to execute.
- * @param delay the time from now to delay execution.
- * @param unit the time unit of the delay parameter.
- * @return a Future representing pending completion of the task,
- * and whose <tt>get()</tt> method will return <tt>null</tt>
- * upon completion.
- * @throws RejectedExecutionException if task cannot be scheduled
- * for execution.
- * @throws NullPointerException if command is null
- */
- public ScheduledFuture<?> schedule(Runnable command, long delay, TimeUnit unit);
-
- /**
- * Creates and executes a ScheduledFuture that becomes enabled after the
- * given delay.
- * @param callable the function to execute.
- * @param delay the time from now to delay execution.
- * @param unit the time unit of the delay parameter.
- * @return a ScheduledFuture that can be used to extract result or cancel.
- * @throws RejectedExecutionException if task cannot be scheduled
- * for execution.
- * @throws NullPointerException if callable is null
- */
- public <V> ScheduledFuture<V> schedule(Callable<V> callable, long delay, TimeUnit unit);
-
- /**
- * 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
- * <tt>initialDelay</tt> then <tt>initialDelay+period</tt>, then
- * <tt>initialDelay + 2 * period</tt>, and so on.
- * If any execution of the task
- * encounters an exception, subsequent executions are suppressed.
- * Otherwise, the task will only terminate via cancellation or
- * termination of the executor.
- * @param command the task to execute.
- * @param initialDelay the time to delay first execution.
- * @param period the period between successive executions.
- * @param unit the time unit of the initialDelay and period parameters
- * @return a Future representing pending completion of the task,
- * and whose <tt>get()</tt> method will throw an exception upon
- * cancellation.
- * @throws RejectedExecutionException if task cannot be scheduled
- * for execution.
- * @throws NullPointerException if command is null
- * @throws IllegalArgumentException if period less than or equal to zero.
- */
- public ScheduledFuture<?> scheduleAtFixedRate(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 delay between the termination of one execution and the
- * commencement of the next. If any execution of the task
- * encounters an exception, subsequent executions are suppressed.
- * Otherwise, the task will only terminate via cancellation or
- * termination of the executor.
- * @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 Future representing pending completion of the task,
- * and whose <tt>get()</tt> method will throw an exception upon
- * cancellation.
- * @throws RejectedExecutionException if task cannot be scheduled
- * for execution.
- * @throws NullPointerException if command is null
- * @throws IllegalArgumentException if delay less than or equal to zero.
- */
- public ScheduledFuture<?> scheduleWithFixedDelay(Runnable command, long initialDelay, long delay, TimeUnit unit);
-
- }