Examples with Combiner com.hazelcast.mapreduce.Combiner used on opensource projects

Example 1 with Combiner

use of com.hazelcast.mapreduce.Combiner in project hazelcast by hazelcast.

the class ThreadsafeCombinerTest method github_issue_3625.

/**
     * Combiner creation is not threadsafe
     *
     * @throws Exception
     */
@Test
public void github_issue_3625() throws Exception {
    class TestCombinerFactory implements CombinerFactory {

        @Override
        public Combiner newCombiner(Object key) {
            return new Combiner() {

                @Override
                public void combine(Object value) {
                }

                @Override
                public Object finalizeChunk() {
                    return null;
                }
            };
        }
    }
    class CreationTask implements Runnable {

        private final CountDownLatch latchStart;

        private final CountDownLatch latchEnd;

        private final AtomicReferenceArray<Combiner> array;

        private final DefaultContext<Integer, Integer> defaultContext;

        private final int index;

        CreationTask(CountDownLatch latchStart, CountDownLatch latchEnd, AtomicReferenceArray<Combiner> array, DefaultContext<Integer, Integer> defaultContext, int index) {
            this.latchStart = latchStart;
            this.latchEnd = latchEnd;
            this.array = array;
            this.defaultContext = defaultContext;
            this.index = index;
        }

        @Override
        public void run() {
            try {
                latchStart.await();
                Combiner combiner = defaultContext.getOrCreateCombiner(1);
                array.set(index, combiner);
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                latchEnd.countDown();
            }
        }
    }
    int threadCount = 20;
    AtomicReferenceArray<Combiner> combiners = new AtomicReferenceArray<Combiner>(threadCount);
    DefaultContext<Integer, Integer> context = new DefaultContext<Integer, Integer>(new TestCombinerFactory(), null);
    CountDownLatch latchStart = new CountDownLatch(1);
    CountDownLatch latchEnd = new CountDownLatch(threadCount);
    for (int i = 0; i < threadCount; i++) {
        Thread t = new Thread(new CreationTask(latchStart, latchEnd, combiners, context, i));
        t.start();
    }
    latchStart.countDown();
    latchEnd.await(1, TimeUnit.MINUTES);
    for (int i = 0; i < threadCount - 1; i++) {
        Combiner c1 = combiners.get(i);
        Combiner c2 = combiners.get(i + 1);
        assertTrue("Returned combiners are not identical: " + c1 + " -> " + c2, c1 == c2);
    }
}