Example usage for java.util.concurrent ArrayBlockingQueue peek

Introduction

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

Prototype

public E peek() 

Source Link

Usage

From source file:com.scvngr.levelup.core.test.SupportLoaderTestCase.java

/**
 * Runs a Loader synchronously and returns the result of the load. The loader will be started,
 * stopped, and destroyed by this method so it cannot be reused.
 *
 * @param loader The loader to run synchronously
 * @return The result from the loader//  w w  w .ja va2s  .co m
 */
public <T> T getLoaderResultSynchronously(final Loader<T> loader) {
    // The test thread blocks on this queue until the loader puts its result in
    final ArrayBlockingQueue<T> queue = new ArrayBlockingQueue<T>(1);
    final CountDownLatch latch = new CountDownLatch(1);

    // This callback runs on the "main" thread and unblocks the test thread
    // when it puts the result into the blocking queue
    final OnLoadCompleteListener<T> listener = new OnLoadCompleteListener<T>() {
        @Override
        public void onLoadComplete(final Loader<T> completedLoader, final T data) {
            // Shut the loader down
            completedLoader.unregisterListener(this);
            completedLoader.stopLoading();
            completedLoader.reset();

            // Store the result, unblocking the test thread
            if (null != data) {
                queue.add(data);
            }
            latch.countDown();
        }
    };

    // This handler runs on the "main" thread of the process since AsyncTask
    // is documented as needing to run on the main thread and many Loaders use
    // AsyncTask
    final Handler mainThreadHandler = new Handler(Looper.getMainLooper()) {
        @Override
        public void handleMessage(final Message msg) {
            loader.registerListener(0, listener);
            loader.startLoading();
        }
    };

    // Ask the main thread to start the loading process
    mainThreadHandler.sendEmptyMessage(0);

    // Block on the queue waiting for the result of the load to be inserted
    T result;
    while (true) {
        try {
            latch.await();
            result = queue.peek();
            break;
        } catch (final InterruptedException e) {
            throw new RuntimeException("waiting thread interrupted", e);
        }
    }

    return result;
}

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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. j a  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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