Example usage for java.util.concurrent LinkedBlockingQueue peek

Introduction

In this page you can find the example usage for java.util.concurrent LinkedBlockingQueue peek.

Prototype

public E peek() 

Source Link

Usage

From source file:com.ibm.crail.tools.CrailBenchmark.java

void collectionTest(int size, int loop) throws Exception {
    System.out.println("collectionTest, size " + size + ", loop " + loop);

    RingBuffer<Object> ringBuffer = new RingBuffer<Object>(10);
    ArrayBlockingQueue<Object> arrayQueue = new ArrayBlockingQueue<Object>(10);
    LinkedBlockingQueue<Object> listQueue = new LinkedBlockingQueue<Object>();

    Object obj = new Object();
    long start = System.currentTimeMillis();
    for (int i = 0; i < loop; i++) {
        for (int j = 0; j < size; j++) {
            ringBuffer.add(obj);/*from w w w .  ja v  a 2s.  c  o  m*/
            Object tmp = ringBuffer.peek();
            tmp = ringBuffer.poll();
        }
    }
    long end = System.currentTimeMillis();
    double executionTime = ((double) (end - start));
    System.out.println("ringbuffer, execution time [ms] " + executionTime);

    start = System.currentTimeMillis();
    for (int i = 0; i < loop; i++) {
        for (int j = 0; j < size; j++) {
            arrayQueue.add(obj);
            Object tmp = arrayQueue.peek();
            tmp = arrayQueue.poll();
        }
    }
    end = System.currentTimeMillis();
    executionTime = ((double) (end - start));
    System.out.println("arrayQueue, execution time [ms] " + executionTime);

    start = System.currentTimeMillis();
    for (int i = 0; i < loop; i++) {
        for (int j = 0; j < size; j++) {
            listQueue.add(obj);
            Object tmp = listQueue.peek();
            tmp = listQueue.poll();
        }
    }
    end = System.currentTimeMillis();
    executionTime = ((double) (end - start));
    System.out.println("arrayQueue, execution time [ms] " + executionTime);
}

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From source file:org.apache.bookkeeper.bookie.LedgerCacheTest.java

/**
 * Race where a flush would fail because a garbage collection occurred at
 * the wrong time./*from   ww w. j  a v  a2  s.  c o  m*/
 * {@link https://issues.apache.org/jira/browse/BOOKKEEPER-604}
 */
@Test(timeout = 60000)
public void testFlushDeleteRace() throws Exception {
    newLedgerCache();
    final AtomicInteger rc = new AtomicInteger(0);
    final LinkedBlockingQueue<Long> ledgerQ = new LinkedBlockingQueue<Long>(1);
    final byte[] masterKey = "masterKey".getBytes();
    Thread newLedgerThread = new Thread() {
        public void run() {
            try {
                for (int i = 0; i < 1000 && rc.get() == 0; i++) {
                    ledgerCache.setMasterKey(i, masterKey);
                    ledgerQ.put((long) i);
                }
            } catch (Exception e) {
                rc.set(-1);
                LOG.error("Exception in new ledger thread", e);
            }
        }
    };
    newLedgerThread.start();

    Thread flushThread = new Thread() {
        public void run() {
            try {
                while (true) {
                    Long id = ledgerQ.peek();
                    if (id == null) {
                        continue;
                    }
                    LOG.info("Put entry for {}", id);
                    try {
                        ledgerCache.putEntryOffset((long) id, 1, 0);
                    } catch (Bookie.NoLedgerException nle) {
                        //ignore
                    }
                    ledgerCache.flushLedger(true);
                }
            } catch (Exception e) {
                rc.set(-1);
                LOG.error("Exception in flush thread", e);
            }
        }
    };
    flushThread.start();

    Thread deleteThread = new Thread() {
        public void run() {
            try {
                while (true) {
                    long id = ledgerQ.take();
                    LOG.info("Deleting {}", id);
                    ledgerCache.deleteLedger(id);
                }
            } catch (Exception e) {
                rc.set(-1);
                LOG.error("Exception in delete thread", e);
            }
        }
    };
    deleteThread.start();

    newLedgerThread.join();
    assertEquals("Should have been no errors", rc.get(), 0);

    deleteThread.interrupt();
    flushThread.interrupt();
}

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