Examples of org.jgroups.util.TimeScheduler

org.jgroups.util.TimeScheduler
Fixed-delay & fixed-rate single thread scheduler
The scheduler supports varying scheduling intervals by asking the task every time for its next preferred scheduling interval. Scheduling can either be fixed-delay or fixed-rate. The notions are borrowed from java.util.Timer and retain the same meaning. I.e. in fixed-delay scheduling, the task's new schedule is calculated as:
new_schedule = time_task_starts + scheduling_interval
In fixed-rate scheduling, the next schedule is calculated as:
new_schedule = time_task_was_supposed_to_start + scheduling_interval
The scheduler internally holds a queue of tasks sorted in ascending order according to their next execution time. A task is removed from the queue if it is cancelled, i.e. if TimeScheduler.Task.isCancelled() returns true.
The scheduler internally uses a java.util.SortedSet to keep tasks sorted. java.util.Timer uses an array arranged as a binary heap that doesn't shrink. It is likely that the latter arrangement is faster.
Initially, the scheduler is in SUSPENDed mode, start() need not be called: if a task is added, the scheduler gets started automatically. Calling start() starts the scheduler if it's suspended or stopped else has no effect. Once stop() is called, added tasks will not restart it: start() has to be called to restart the scheduler.

    static final double       PERCENTAGE_OFF=1.3; // how much can expected xmit_timeout and real timeout differ to still be okay ?
    final Map<Long,Entry>     msgs=new ConcurrentHashMap<Long,Entry>(); // keys=seqnos (Long), values=Entries


    @DataProvider(name="provider")
    Object[][] provider() {
        final TimeScheduler timer=new DefaultTimeScheduler(10);
        return new Object[][] {
                {timer,
                 new AckSenderWindow(new MyRetransmitCommand(), new StaticInterval(xmit_timeouts), timer)}
        };
    }

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    public void testShutdownOfTimer() throws Exception {
        a=createSharedChannel(SINGLETON_1);
        b=createSharedChannel(SINGLETON_1);
        a.connect("x");
        b.connect("y");
        TimeScheduler timer1=a.getProtocolStack().getTransport().getTimer();
        TimeScheduler timer2=b.getProtocolStack().getTransport().getTimer();


        assert timer1 == timer2;


        assert !timer1.isShutdown();
        assert !timer2.isShutdown();


        Util.sleep(500);
        b.close();


        assert !timer2.isShutdown();
        assert !timer1.isShutdown();


        a.close(); // now, reference counting reaches 0, so the timer thread pool is stopped
        assert timer2.isShutdown();
        assert timer1.isShutdown();
    }

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    }




    public void setUp() throws Exception {
        super.setUp();
        timer=new TimeScheduler();
    }

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     * retransmission attempts
     *
     * @throws IllegalArgumentException if <code>cmd</code> is null
     */
    public AckMcastSenderWindow(RetransmitCommand cmd, long[] retransmit_intervals) {
  init(cmd, retransmit_intervals, new TimeScheduler(SUSPEND_TIMEOUT), true);
    }

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     * Create a new Retransmitter associated with the given sender address
     * @param sender the address from which retransmissions are expected or to which retransmissions are sent
     * @param cmd the retransmission callback reference
     */
    public Retransmitter(Address sender, RetransmitCommand cmd) {
        init(sender, cmd, new TimeScheduler(SUSPEND_TIMEOUT), true);
    }

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     * i. Set the gossip task scheduler
     * ii. Reset the layer's state.
     * iii. Start the gossiping task
     */
    public void start() throws Exception {
        TimeScheduler timer;


        super.start();
        timer=stack != null ? stack.timer : null;
        if(timer == null)
            throw new Exception("STABLE.start(): timer is null");

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     * @deprecated Use {@link org.jgroups.protocols.TP#getTimer()} to fetch the timer and call getCorePoolSize() directly
     * @return
     */
    public int getTimerThreads() {
        TP transport=getTransport();
        TimeScheduler timer;
        if(transport != null) {
            timer=transport.getTimer();
            if(timer != null)
                return timer.getCorePoolSize();
        }
        return -1;
    }

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     * transport and then invoke the method on it
     * @return
     */
    public String dumpTimerQueue() {
        TP transport=getTransport();
        TimeScheduler timer;
        if(transport != null) {
            timer=transport.getTimer();
            if(timer != null)
                return timer.dumpTaskQueue();
        }
        return "";
    }

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     * @param retransmit_intervals the interval between two consecutive
     *                             retransmission attempts
     * @throws IllegalArgumentException if <code>cmd</code> is null
     */
    public AckMcastSenderWindow(RetransmitCommand cmd, Interval retransmit_intervals) {
        init(cmd, retransmit_intervals, new TimeScheduler(), true);
    }

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            catch(InterruptedException e) {
            }
        }
        this.timer=timer;
        if(this.timer == null)
            this.timer=new TimeScheduler();
    }

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Related Classes of org.jgroups.util.TimeScheduler

org.jgroups.debug.Simulator$ProtocolAdapter

org.jgroups.protocols.STABLE

org.jgroups.protocols.TOTAL

org.jgroups.stack.AckMcastSenderWindow

org.jgroups.stack.GossipClient

org.jgroups.stack.ProtocolStack

org.jgroups.stack.Retransmitter

org.jgroups.tests.AckSenderWindowStressTest

org.jgroups.tests.AckSenderWindowTest

org.jgroups.tests.NAKACK_SET_DIGEST_Test

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