Example usage for java.util.concurrent ConcurrentSkipListSet pollFirst

Introduction

In this page you can find the example usage for java.util.concurrent ConcurrentSkipListSet pollFirst.

Prototype

public E pollFirst() 

Source Link

Usage

From source file:org.apache.hadoop.hbase.procedure2.TestProcedureSchedulerConcurrency.java

private void testConcurrentWaitWake(final boolean useWakeBatch) throws Exception {
    final int WAIT_THRESHOLD = 2500;
    final int NPROCS = 20;
    final int NRUNS = 500;

    final ProcedureScheduler sched = procSched;
    for (long i = 0; i < NPROCS; ++i) {
        sched.addBack(new TestProcedureWithEvent(i));
    }//from  w w  w  . j  av  a2s  . co m

    final Thread[] threads = new Thread[4];
    final AtomicInteger waitCount = new AtomicInteger(0);
    final AtomicInteger wakeCount = new AtomicInteger(0);

    final ConcurrentSkipListSet<TestProcedureWithEvent> waitQueue = new ConcurrentSkipListSet<TestProcedureWithEvent>();
    threads[0] = new Thread() {
        @Override
        public void run() {
            long lastUpdate = 0;
            while (true) {
                final int oldWakeCount = wakeCount.get();
                if (useWakeBatch) {
                    ProcedureEvent[] ev = new ProcedureEvent[waitQueue.size()];
                    for (int i = 0; i < ev.length; ++i) {
                        ev[i] = waitQueue.pollFirst().getEvent();
                        LOG.debug("WAKE BATCH " + ev[i] + " total=" + wakeCount.get());
                    }
                    sched.wakeEvents(ev.length, ev);
                    wakeCount.addAndGet(ev.length);
                } else {
                    int size = waitQueue.size();
                    while (size-- > 0) {
                        ProcedureEvent ev = waitQueue.pollFirst().getEvent();
                        sched.wakeEvent(ev);
                        LOG.debug("WAKE " + ev + " total=" + wakeCount.get());
                        wakeCount.incrementAndGet();
                    }
                }
                if (wakeCount.get() != oldWakeCount) {
                    lastUpdate = System.currentTimeMillis();
                } else if (wakeCount.get() >= NRUNS
                        && (System.currentTimeMillis() - lastUpdate) > WAIT_THRESHOLD) {
                    break;
                }
                Threads.sleepWithoutInterrupt(25);
            }
        }
    };

    for (int i = 1; i < threads.length; ++i) {
        threads[i] = new Thread() {
            @Override
            public void run() {
                while (true) {
                    TestProcedureWithEvent proc = (TestProcedureWithEvent) sched.poll();
                    if (proc == null)
                        continue;

                    sched.suspendEvent(proc.getEvent());
                    waitQueue.add(proc);
                    sched.waitEvent(proc.getEvent(), proc);
                    LOG.debug("WAIT " + proc.getEvent());
                    if (waitCount.incrementAndGet() >= NRUNS) {
                        break;
                    }
                }
            }
        };
    }

    for (int i = 0; i < threads.length; ++i) {
        threads[i].start();
    }
    for (int i = 0; i < threads.length; ++i) {
        threads[i].join();
    }

    sched.clear();
}

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