Example usage for org.apache.zookeeper Watcher Watcher

Introduction

In this page you can find the example usage for org.apache.zookeeper Watcher Watcher.

Prototype

Watcher

Source Link

Usage

From source file:com.twitter.common.zookeeper.ZooKeeperMap.java

License:Apache License

private synchronized void watchChildren()
        throws InterruptedException, KeeperException, ZooKeeperConnectionException {

    /*//from   www  .  j  av  a2s  .c  o  m
     * Add a watch on the parent node itself, and attempt to rewatch if it
     * gets deleted
     */
    zkClient.get().exists(nodePath, new Watcher() {
        @Override
        public void process(WatchedEvent event) {
            if (event.getType() == Watcher.Event.EventType.NodeDeleted) {
                // If the parent node no longer exists
                localMap.clear();
                try {
                    tryWatchChildren();
                } catch (InterruptedException e) {
                    LOG.log(Level.WARNING, "Interrupted while trying to watch children.", e);
                    Thread.currentThread().interrupt();
                }
            }
        }
    });

    final Watcher childWatcher = new Watcher() {
        @Override
        public void process(WatchedEvent event) {
            if (event.getType() == Watcher.Event.EventType.NodeChildrenChanged) {
                try {
                    tryWatchChildren();
                } catch (InterruptedException e) {
                    LOG.log(Level.WARNING, "Interrupted while trying to watch children.", e);
                    Thread.currentThread().interrupt();
                }
            }
        }
    };

    List<String> children = zkClient.get().getChildren(nodePath, childWatcher);
    updateChildren(Sets.newHashSet(children));
}

From source file:com.twitter.common.zookeeper.ZooKeeperMap.java

License:Apache License

private void addChild(final String child)
        throws InterruptedException, KeeperException, ZooKeeperConnectionException {

    final Watcher nodeWatcher = new Watcher() {
        @Override//from w  w w  . j a v  a 2s  . co  m
        public void process(WatchedEvent event) {
            if (event.getType() == Watcher.Event.EventType.NodeDataChanged) {
                try {
                    tryAddChild(child);
                } catch (InterruptedException e) {
                    LOG.log(Level.WARNING, "Interrupted while trying to add a child.", e);
                    Thread.currentThread().interrupt();
                }
            } else if (event.getType() == Watcher.Event.EventType.NodeDeleted) {
                removeEntry(child);
            }
        }
    };

    try {
        V value = deserializer.apply(zkClient.get().getData(makePath(child), nodeWatcher, null));
        putEntry(child, value);
    } catch (KeeperException.NoNodeException e) {
        // This node doesn't exist anymore, remove it from the map and we're done.
        removeEntry(child);
    }
}

From source file:com.twitter.distributedlog.BKLogHandler.java

License:Apache License

Watcher registerExpirationHandler(final ZooKeeperClient.ZooKeeperSessionExpireNotifier onExpired) {
    if (conf.getZKNumRetries() > 0) {
        return new Watcher() {
            @Override//from w  ww .j a  v  a2 s  .co m
            public void process(WatchedEvent event) {
                // nop
            }
        };
    }
    return zooKeeperClient.registerExpirationHandler(onExpired);
}

From source file:com.twitter.distributedlog.LocalDLMEmulator.java

License:Apache License

public static ZooKeeper connectZooKeeper(String zkHost, int zkPort, int zkTimeoutSec)
        throws IOException, KeeperException, InterruptedException {
    final CountDownLatch latch = new CountDownLatch(1);
    final String zkHostPort = zkHost + ":" + zkPort;

    ZooKeeper zkc = new ZooKeeper(zkHostPort, zkTimeoutSec * 1000, new Watcher() {
        public void process(WatchedEvent event) {
            if (event.getState() == Event.KeeperState.SyncConnected) {
                latch.countDown();/*  www. j  a  va 2 s . c o  m*/
            }
        }
    });
    if (!latch.await(zkTimeoutSec, TimeUnit.SECONDS)) {
        throw new IOException("Zookeeper took too long to connect");
    }
    return zkc;
}

From source file:com.twitter.distributedlog.TestZooKeeperClient.java

License:Apache License

private void expireZooKeeperSession(ZooKeeper zk, int timeout)
        throws IOException, InterruptedException, KeeperException {
    final CountDownLatch latch = new CountDownLatch(1);

    ZooKeeper newZk = new ZooKeeper(zkServers, timeout, new Watcher() {
        @Override/* w w  w  . j a va2s.c  o m*/
        public void process(WatchedEvent event) {
            if (event.getType() == EventType.None && event.getState() == KeeperState.SyncConnected) {
                latch.countDown();
            }
        }
    }, zk.getSessionId(), zk.getSessionPasswd());

    if (!latch.await(timeout, TimeUnit.MILLISECONDS)) {
        throw KeeperException.create(KeeperException.Code.CONNECTIONLOSS);
    }

    newZk.close();
}

From source file:com.twitter.distributedlog.TestZooKeeperClient.java

License:Apache License

private CountDownLatch awaitConnectionEvent(final KeeperState state, final ZooKeeperClient zkc) {
    final CountDownLatch connected = new CountDownLatch(1);
    Watcher watcher = new Watcher() {
        @Override//w  w w .ja v a 2s. c  o m
        public void process(WatchedEvent event) {
            if (event.getType() == EventType.None && event.getState() == state) {
                connected.countDown();
            }
        }
    };
    zkc.register(watcher);
    return connected;
}

From source file:com.twitter.distributedlog.TestZooKeeperClient.java

License:Apache License

@Test(timeout = 60000)
public void testExceptionOnWatchers() throws Exception {
    TestWatcher w1 = new TestWatcher();
    TestWatcher w2 = new TestWatcher();

    final CountDownLatch latch = new CountDownLatch(2);
    w1.setLatch(latch);// w  w  w. j  a va2s .  co m
    w2.setLatch(latch);

    zkc.register(w1);
    zkc.register(w2);
    // register bad watcher
    zkc.register(new Watcher() {
        @Override
        public void process(WatchedEvent event) {
            throw new NullPointerException("bad watcher returning null");
        }
    });

    assertEquals(3, zkc.watchers.size());

    final String zkPath = "/test-exception-on-watchers";

    zkc.get().create(zkPath, new byte[0], ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
    zkc.get().getData(zkPath, true, new Stat());

    zkc.get().setData(zkPath, "first-set".getBytes(), -1);
    latch.await();
    assertEquals(1, w1.receivedEvents.size());
    assertEquals(zkPath, w1.receivedEvents.get(0).getPath());
    assertEquals(Watcher.Event.EventType.NodeDataChanged, w1.receivedEvents.get(0).getType());
    assertEquals(1, w2.receivedEvents.size());
    assertEquals(zkPath, w2.receivedEvents.get(0).getPath());
    assertEquals(Watcher.Event.EventType.NodeDataChanged, w2.receivedEvents.get(0).getType());
}

From source file:com.twitter.distributedlog.zk.TestZKWatcherManager.java

License:Apache License

@Test(timeout = 60000)
public void testRegisterUnregisterWatcher() throws Exception {
    ZKWatcherManager watcherManager = ZKWatcherManager.newBuilder().name("test-register-unregister-watcher")
            .statsLogger(NullStatsLogger.INSTANCE).build();
    String path = "/test-register-unregister-watcher";
    final List<WatchedEvent> events = new LinkedList<WatchedEvent>();
    final CountDownLatch latch = new CountDownLatch(2);
    Watcher watcher = new Watcher() {
        @Override//from   w w  w.j a  va 2  s .  c o  m
        public void process(WatchedEvent event) {
            events.add(event);
            latch.countDown();
        }
    };
    watcherManager.registerChildWatcher(path, watcher);

    // fire the event
    WatchedEvent event0 = new WatchedEvent(Watcher.Event.EventType.NodeCreated,
            Watcher.Event.KeeperState.SyncConnected, path);
    WatchedEvent event1 = new WatchedEvent(Watcher.Event.EventType.None,
            Watcher.Event.KeeperState.SyncConnected, path);
    WatchedEvent event2 = new WatchedEvent(Watcher.Event.EventType.NodeChildrenChanged,
            Watcher.Event.KeeperState.SyncConnected, path);
    watcher.process(event1);
    watcher.process(event2);

    latch.await();

    assertEquals(2, events.size());
    assertEquals(event1, events.get(0));
    assertEquals(event2, events.get(1));

    // unregister watcher
    watcherManager.unregisterChildWatcher(path, watcher);

    assertEquals(0, watcherManager.childWatches.size());
}

From source file:com.twitter.distributedlog.ZooKeeperClient.java

License:Apache License

private ZooKeeper buildZooKeeper() throws ZooKeeperConnectionException, InterruptedException {
    Watcher watcher = new Watcher() {
        @Override/*from  w  ww.  j  av  a2  s. co  m*/
        public void process(WatchedEvent event) {
            switch (event.getType()) {
            case None:
                switch (event.getState()) {
                case Expired:
                    if (null == retryPolicy) {
                        LOG.info("ZooKeeper {}' session expired. Event: {}", name, event);
                        closeInternal();
                    }
                    authenticated = false;
                    break;
                case Disconnected:
                    if (null == retryPolicy) {
                        LOG.info("ZooKeeper {} is disconnected from zookeeper now,"
                                + " but it is OK unless we received EXPIRED event.", name);
                    }
                    // Mark as not authenticated if expired or disconnected. In both cases
                    // we lose any attached auth info. Relying on Expired/Disconnected is
                    // sufficient since all Expired/Disconnected events are processed before
                    // all SyncConnected events, and the underlying member is not updated until
                    // SyncConnected is received.
                    authenticated = false;
                    break;
                default:
                    break;
                }
            }

            try {
                for (Watcher watcher : watchers) {
                    try {
                        watcher.process(event);
                    } catch (Throwable t) {
                        LOG.warn("Encountered unexpected exception from watcher {} : ", watcher, t);
                    }
                }
            } catch (Throwable t) {
                LOG.warn("Encountered unexpected exception when firing watched event {} : ", event, t);
            }
        }
    };

    Set<Watcher> watchers = new HashSet<Watcher>();
    watchers.add(watcher);

    ZooKeeper zk;
    try {
        RetryPolicy opRetryPolicy = null == retryPolicy
                ? new BoundExponentialBackoffRetryPolicy(sessionTimeoutMs, sessionTimeoutMs, 0)
                : retryPolicy;
        RetryPolicy connectRetryPolicy = null == retryPolicy
                ? new BoundExponentialBackoffRetryPolicy(sessionTimeoutMs, sessionTimeoutMs, 0)
                : new BoundExponentialBackoffRetryPolicy(sessionTimeoutMs, sessionTimeoutMs, Integer.MAX_VALUE);
        zk = org.apache.bookkeeper.zookeeper.ZooKeeperClient.newBuilder().connectString(zooKeeperServers)
                .sessionTimeoutMs(sessionTimeoutMs).watchers(watchers).operationRetryPolicy(opRetryPolicy)
                .connectRetryPolicy(connectRetryPolicy).statsLogger(statsLogger)
                .retryThreadCount(retryThreadCount).requestRateLimit(requestRateLimit).build();
    } catch (KeeperException e) {
        throw new ZooKeeperConnectionException("Problem connecting to servers: " + zooKeeperServers, e);
    } catch (IOException e) {
        throw new ZooKeeperConnectionException("Problem connecting to servers: " + zooKeeperServers, e);
    }
    return zk;
}

From source file:com.twitter.distributedlog.ZooKeeperClient.java

License:Apache License

/**
 * Clients that need to re-establish state after session expiration can register an
 * {@code onExpired} command to execute.
 *
 * @param onExpired the {@code Command} to register
 * @return the new {@link Watcher} which can later be passed to {@link #unregister} for
 *         removal./*from  w  w  w. j  av a  2 s. co m*/
 */
public Watcher registerExpirationHandler(final ZooKeeperSessionExpireNotifier onExpired) {
    Watcher watcher = new Watcher() {
        @Override
        public void process(WatchedEvent event) {
            if (event.getType() == EventType.None && event.getState() == KeeperState.Expired) {
                try {
                    onExpired.notifySessionExpired();
                } catch (Exception exc) {
                    // do nothing
                }
            }
        }
    };
    register(watcher);
    return watcher;
}