Examples of com.hazelcast.core.ISemaphore

com.hazelcast.core.ISemaphore
ISemaphore is a backed-up distributed alternative to the {@link java.util.concurrent.Semaphore}.
ISemaphore is a cluster-wide counting semaphore. Conceptually, it maintains a set of permits. Each {@link #acquire()} blocks if necessary untila permit is available, and then takes it. Each {@link #release()} adds a permit,potentially releasing a blocking acquirer. However, no actual permit objects are used; the semaphore just keeps a count of the number available and acts accordingly.
The Hazelcast distributed semaphore implementation guarantees that threads invoking any of the {@link #acquire() acquire} methods are selectedto obtain permits in the order in which their invocation of those methods was processed(first-in-first-out; FIFO). Note that FIFO ordering necessarily applies to specific internal points of execution within the cluster. So, it is possible for one member to invoke {@code acquire} before another, but reachthe ordering point after the other, and similarly upon return from the method.
This class also provides convenience methods to {@link #acquire(int) acquire} and {@link #release(int) release} multiplepermits at a time. Beware of the increased risk of indefinite postponement when using the multiple acquire. If a single permit is released to a semaphore that is currently blocking, a thread waiting for one permit will acquire it before a thread waiting for multiple permits regardless of the call order.
- Correct usage of a semaphore is established by programming convention in the application.

        assertEquals(semaphore.availablePermits(), 0);
    }


    @Test(timeout = 30000)
    public void testTryAcquireMultiple_whenArgumentNegative() {
        final ISemaphore semaphore = hz.getSemaphore(randomString());
        int negativePermits = -5;
        semaphore.init(0);
        try {
            semaphore.tryAcquire(negativePermits);
            fail();
        } catch (IllegalArgumentException e) {
            e.printStackTrace();
        }
        assertEquals(0, semaphore.availablePermits());
    }

View Full Code Here

        assertEquals(0, semaphore.availablePermits());
    }


    @Test(timeout = 30000)
    public void testTryAcquire_whenNotEnoughPermits() throws InterruptedException {
        final ISemaphore semaphore = hz.getSemaphore(randomString());
        int numberOfPermits = 10;
        semaphore.init(numberOfPermits);
        semaphore.acquire(10);
        boolean result = semaphore.tryAcquire(1);


        assertFalse(result);
        assertEquals(0, semaphore.availablePermits());
    }

View Full Code Here

        assertEquals(0, semaphore.availablePermits());
    }


    @Test(timeout = 30000)
    public void testInit_whenNotIntialized() {
        ISemaphore semaphore = hz.getSemaphore(randomString());


        boolean result = semaphore.init(2);


        assertTrue(result);
        assertEquals(2, semaphore.availablePermits());
    }

View Full Code Here

        assertEquals(2, semaphore.availablePermits());
    }


    @Test(timeout = 30000)
    public void testInit_whenAlreadyIntialized() {
        ISemaphore semaphore = hz.getSemaphore(randomString());
        semaphore.init(2);


        boolean result = semaphore.init(4);


        assertFalse(result);
        assertEquals(2, semaphore.availablePermits());
    }

View Full Code Here

    @Test
    public void testSemaphore() throws Exception {
        String partitionKey = "hazelcast";
        HazelcastInstance hz = getHazelcastInstance(partitionKey);


        ISemaphore semaphore = hz.getSemaphore("semaphore@" + partitionKey);
        semaphore.release();
        assertEquals("semaphore@" + partitionKey, semaphore.getName());
        assertEquals(partitionKey, semaphore.getPartitionKey());


        SemaphoreService service = getNodeEngine(hz).getService(SemaphoreService.SERVICE_NAME);
        assertTrue(service.containsSemaphore(semaphore.getName()));
    }

View Full Code Here

    @Test
    public void testObjectWithPartitionKeyAndTask() throws Exception {
        HazelcastInstance instance = instances[0];
        IExecutorService executorServices = instance.getExecutorService("executor");
        String partitionKey = "hazelcast";
        ISemaphore semaphore = instance.getSemaphore("foobar@" + partitionKey);
        semaphore.release();
        ContainsSemaphoreTask task = new ContainsSemaphoreTask(semaphore.getName());
        Future<Boolean> f = executorServices.submitToKeyOwner(task, semaphore.getPartitionKey());
        assertTrue(f.get());
    }

View Full Code Here

        String mapKey = "key@" + partitionKey;
        IMap map = instance.getMap("map");


        map.put(mapKey, "foobar");


        ISemaphore semaphore = instance.getSemaphore("s@" + partitionKey);
        semaphore.release();


        ContainsSemaphoreAndMapEntryTask task = new ContainsSemaphoreAndMapEntryTask(semaphore.getName(), mapKey);
        Map<Member, Future<Boolean>> futures = executorServices.submitToAllMembers(task);


        int count = 0;
        for (Future<Boolean> f : futures.values()) {
            count += f.get() ? 1 : 0;

View Full Code Here

        assertEquals(0, semaphore.availablePermits());
    }


    @Test
    public void testTryAcquire_whenAvailable() throws Exception {
        final ISemaphore semaphore = client.getSemaphore(randomString());
        semaphore.init(1);
        assertTrue(semaphore.tryAcquire());
    }

View Full Code Here

        assertTrue(semaphore.tryAcquire());
    }


    @Test
    public void testTryAcquire_whenUnAvailable() throws Exception {
        final ISemaphore semaphore = client.getSemaphore(randomString());
        semaphore.init(0);
        assertFalse(semaphore.tryAcquire());
    }

View Full Code Here

        assertFalse(semaphore.tryAcquire());
    }


    @Test
    public void testTryAcquire_whenAvailableWithTimeOut() throws Exception {
        final ISemaphore semaphore = client.getSemaphore(randomString());
        semaphore.init(1);
        assertTrue(semaphore.tryAcquire(1, TimeUnit.MILLISECONDS));
    }

View Full Code Here

0 1 2 3 4 5

TOP

Related Classes of com.hazelcast.core.ISemaphore

com.hazelcast.client.semaphore.ClientSemaphoreTest

com.hazelcast.client.semaphore.ClientSemaphoreThreadedTest

com.hazelcast.concurrent.semaphore.AdvancedSemaphoreTest

com.hazelcast.concurrent.semaphore.SemaphoreClientRequestTest

com.hazelcast.concurrent.semaphore.SemaphoreTest

com.hazelcast.partition.PartitionControlledIdTest

All source code are property of their respective owners. Java is a trademark of Sun Microsystems, Inc and owned by ORACLE Inc. Contact coftware#gmail.com.