Example usage for org.apache.hadoop.io.retry RetryPolicy RetryPolicy

Introduction

In this page you can find the example usage for org.apache.hadoop.io.retry RetryPolicy RetryPolicy.

Prototype

RetryPolicy

Source Link

Usage

From source file:com.proofpoint.zookeeper.TestZookeeperClient.java

License:Apache License

@Test
public void testRetries() throws Exception {
    ZookeeperTestServerInstance testServer = new ZookeeperTestServerInstance();

    final AtomicInteger retryCount = new AtomicInteger(0);
    Map<String, String> props = Maps.newHashMap();
    props.put("zookeeper.connection-string", testServer.getConnectString());
    ConfigurationFactory factory = new ConfigurationFactory(props);
    ZookeeperClientConfig zookeeperClientConfig = factory.build(ZookeeperClientConfig.class);
    zookeeperClientConfig.setConnectionTimeoutInMs(1000);

    ZookeeperClient client = new ZookeeperClient(zookeeperClientConfig).setRetryPolicy(new RetryPolicy() {
        @Override//from  ww w .ja  va2 s . c  o  m
        public boolean shouldRetry(Exception e, int retries) throws Exception {
            retryCount.incrementAndGet();
            return retries < 1;
        }
    });
    client.exists("/"); // blocks until connection is achieved

    final AtomicReference<CountDownLatch> latch = new AtomicReference<CountDownLatch>(new CountDownLatch(1));
    client.setErrorHandler(new ZookeeperClientErrorHandler() {
        @Override
        public void connectionLost(ZookeeperClient client) {
            latch.get().countDown();
        }
    });

    testServer.close(); // next client call causes a retry

    try {
        client.exists("/");
        fail();
    } catch (Exception e) {
        // correct
    }
    assertEquals(retryCount.get(), 2);
    Assert.assertTrue(latch.get().await(10, TimeUnit.SECONDS));

    latch.set(new CountDownLatch(1));
    retryCount.set(0);

    // now try with a background call that should succeed

    testServer = new ZookeeperTestServerInstance();
    zookeeperClientConfig.setConnectionString(testServer.getConnectString());

    client.inBackground("").exists("/");
    assertEquals(retryCount.get(), 0);
    assertEquals(latch.get().getCount(), 1);

    client.closeForShutdown();
}

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