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:org.deeplearning4j.zookeeper.TestZookeeperRegister.java

License:Apache License

@Test
public void testZookeeper() throws Exception {
    String host = "localhost";

    register.register();/*from ww w.j  a  v  a 2s .c  om*/
    String path = new ZookeeperPathBuilder().setHost(host).setPort(2181).addPaths(Arrays.asList("tmp", "test"))
            .build();

    assumeNotNull(keeper.getData(path, new Watcher() {

        @Override
        public void process(WatchedEvent event) {
            log.info("Event " + event);

        }

    }, new Stat()));

    Configuration retrieve = retriever.retrieve();
    assumeNotNull(retrieve);

    keeper.delete(path, -1);

}

---

From source file:org.eclipse.gyrex.cloud.internal.admin.NodeConfigurer.java

License:Open Source License

@Override
public IStatus configureConnection(final String connectString) {
    ZooKeeper zk = null;/* w w  w . j  av  a2s .c o m*/
    try {
        if (connectString != null) {
            // try connect
            // TODO: not sure if this makes sense when configuring a remote system
            final CountDownLatch connected = new CountDownLatch(1);
            zk = new ZooKeeper(connectString, 5000, new Watcher() {

                @Override
                public void process(final WatchedEvent event) {
                    if ((event.getType() == EventType.None)
                            && (event.getState() == KeeperState.SyncConnected)) {
                        connected.countDown();
                    }
                }
            });

            // wait at most 5 seconds for a connection
            connected.await(5000, TimeUnit.MILLISECONDS);

            if (zk.getState() != States.CONNECTED) {
                throw new IllegalStateException(String.format(
                        "Timeout waiting for a connection to '%s'. Please verify the connect string.",
                        connectString));
            }

            // try reading some information from the cloud
            if (null == zk.exists(IZooKeeperLayout.PATH_GYREX_ROOT.toString(), false)) {
                // maybe a new cloud, try initialization
                final String path = IZooKeeperLayout.PATH_GYREX_ROOT.toString();
                final String createdPath = zk.create(path, null, ZooDefs.Ids.OPEN_ACL_UNSAFE,
                        CreateMode.PERSISTENT);
                if (!path.equals(createdPath)) {
                    throw new IllegalStateException(String
                            .format("created path does not match expected path (%s != %s)", path, createdPath));
                }
            }

            // at this point the connect string seems to be ok
            // TODO: store it in ZooKeeper and implement ZK to local sync
        }

        // store in instance preferences if local
        if (new NodeInfo().getNodeId().equals(nodeId)) {
            final Preferences preferences = InstanceScope.INSTANCE.getNode(CloudActivator.SYMBOLIC_NAME)
                    .node(ZooKeeperGateConfig.PREF_NODE_ZOOKEEPER);
            if (connectString != null) {
                preferences.put(ZooKeeperGateConfig.PREF_KEY_CLIENT_CONNECT_STRING, connectString);
            } else {
                preferences.remove(ZooKeeperGateConfig.PREF_KEY_CLIENT_CONNECT_STRING);
            }
            preferences.flush();

            // remove connection to cloud
            CloudState.unregisterNode();

            // bring down ZooKeeper Gate
            ZooKeeperGateApplication.reconnect();

            // register with new cloud
            CloudState.registerNode();
        }
    } catch (final Exception e) {
        LOG.debug("Exception connecting to cloud using connect string {}.", connectString, e);
        return new Status(IStatus.ERROR, CloudActivator.SYMBOLIC_NAME,
                "Unable to connect to ZooKeeper. " + ExceptionUtils.getRootCauseMessage(e), e);
    } finally {
        if (zk != null) {
            try {
                zk.close();
            } catch (final InterruptedException e) {
                Thread.currentThread().interrupt();
            }
        }
    }

    return Status.OK_STATUS;
}

---

From source file:org.fusesource.meshkeeper.distribution.registry.zk.ZooKeeperChildWatcher.java

License:Open Source License

public ZooKeeperChildWatcher(ZooKeeper zk, String path) {
    this.zk = zk;
    this.path = path;
    this.watcher = new Watcher() {

        public void process(WatchedEvent event) {
            switch (event.getType()) {
            case NodeChildrenChanged: {
                //System.out.println("NodeChildrenChangedEvent");
                watch();/*from w w  w .  ja  v a  2s .  c o m*/
                break;
            }
            default: {
                System.out.println("WARNING Got:" + event);
            }
            }
        }
    };

    this.callback = new ChildrenCallback() {

        public void processResult(int rc, String path, Object ctx, List<String> children) {
            handleChildUpdate(path, children);
        }
    };

}

---

From source file:org.fusesource.meshkeeper.distribution.registry.zk.ZooKeeperRegistry.java

License:Open Source License

public void start() throws Exception {
    synchronized (this) {
        if (zk == null) {
            //ZK doesn't like schemes, so just take host and port
            URI uri = new URI(connectUrl);

            zk = new ZooKeeper(uri.getHost() + ":" + uri.getPort(), sessionTimeout, new Watcher() {
                public void process(WatchedEvent event) {
                    switch (event.getState()) {
                    case SyncConnected:
                        connected.countDown();
                        break;

                    }/*from ww  w  .  j a va2 s.  co  m*/
                }
            });
            zk.addAuthInfo("digest", (userid + ":" + password).getBytes());

        }
    }

    // Wait for the client to establish a connection.
    if (connectTimeout > 0) {
        if (!connected.await(connectTimeout, TimeUnit.MILLISECONDS)) {
            throw new IOException("Failed to connect to ZooKeeper at " + connectUrl + " within "
                    + connectTimeout + " milliseconds.");
        }
    } else {
        connected.await();
    }
}

---

From source file:org.glassfish.grizzly.memcached.zookeeper.ZKClient.java

License:Open Source License

/**
 * Connect this client to the zookeeper server
 * <p/>//from   ww  w  . j a  v a2s . c  o  m
 * this method will wait for {@link Watcher.Event.KeeperState#SyncConnected} from the zookeeper server.
 *
 * @throws IOException          the io exception of internal ZooKeeper
 * @throws InterruptedException the interrupted exception of internal ZooKeeper
 */
public boolean connect() throws IOException, InterruptedException {
    lock.lock();
    try {
        if (connected) {
            return true;
        }
        zooKeeper = new ZooKeeper(zooKeeperServerList, (int) sessionTimeoutInMillis,
                new InternalWatcher(new Watcher() {

                    @Override
                    public void process(WatchedEvent event) {
                    }
                }));
        if (!ensureConnected(connectTimeoutInMillis)) {
            zooKeeper.close();
            currentState = Watcher.Event.KeeperState.Disconnected;
            connected = false;
        } else {
            connected = true;
            if (logger.isLoggable(Level.FINE)) {
                logger.log(Level.FINE, "connected the zookeeper server successfully");
            }
        }
        return connected;
    } finally {
        lock.unlock();
    }
}

---

From source file:org.goldenorb.zookeeper.OrbSimpleZKTest.java

License:Apache License

/**
 * //ww w  . jav a 2  s  .co  m
 */
@Test
public void connectToZooKeeper() throws IOException, InterruptedException {
    ZooKeeper zk = new ZooKeeper("localhost:21810", 5000, new Watcher() {
        @Override
        public void process(WatchedEvent event) {
            System.out.println(event);
        }
    });

    zk.close();
}

---

From source file:org.lable.oss.uniqueid.zookeeper.connection.ZooKeeperConnection.java

License:Apache License

/**
 * Connect to the ZooKeeper quorum, or timeout if it is unreachable.
 *
 * @throws IOException Thrown when connecting to the ZooKeeper quorum fails.
 *//*  ww  w  . j av a 2s. c  om*/
private static void connect() throws IOException {
    final CountDownLatch latch = new CountDownLatch(1);
    ZooKeeper zookeeper;

    // Connect to the quorum and wait for the successful connection callback.;
    zookeeper = new ZooKeeper(quorumAddresses, (int) SECONDS.toMillis(10), new Watcher() {
        @Override
        public void process(WatchedEvent watchedEvent) {
            if (watchedEvent.getState() == Event.KeeperState.SyncConnected) {
                // Signal that the Zookeeper connection is established.
                latch.countDown();
            }
        }
    });

    boolean successfullyConnected = false;
    try {
        successfullyConnected = latch.await(11, SECONDS);
    } catch (InterruptedException e) {
        Thread.currentThread().interrupt();
    }
    if (!successfullyConnected) {
        throw new IOException(String.format("Connection to ZooKeeper quorum timed out after %d seconds.",
                CONNECTION_TIMEOUT));
    }

    zookeeper.register(new ConnectionWatcher());

    INSTANCE.zookeeper = zookeeper;
}

---

From source file:org.lable.oss.uniqueid.zookeeper.ResourceClaim.java

License:Apache License

/**
 * Wait in the queue until the znode in front of us changes.
 *
 * @param zookeeper ZooKeeper connection to use.
 * @param lockNode Path to the znode representing the locking queue.
 * @param placeInLine Name of our current position in the queue.
 * @return Name of the first node in the queue, when we are it.
 * @throws KeeperException/* w  ww  . ja  v a 2  s.  c o  m*/
 * @throws InterruptedException
 */
static String waitInLine(ZooKeeper zookeeper, String lockNode, String placeInLine)
        throws KeeperException, InterruptedException {

    // Get the list of nodes in the queue, and find out what our position is.
    List<String> children = zookeeper.getChildren(lockNode, false);

    // The list returned is unsorted.
    Collections.sort(children);

    if (children.size() == 0) {
        // Only possible if some other process cancelled our ticket.
        logger.warn("getChildren() returned empty list, but we created a ticket.");
        return acquireLock(zookeeper, lockNode);
    }

    boolean lockingTicketExists = children.get(0).equals(LOCKING_TICKET);
    if (lockingTicketExists) {
        children.remove(0);
    }

    // Where are we in the queue?
    int positionInQueue = -1;
    int i = 0;
    for (String child : children) {
        if (child.equals(placeInLine)) {
            positionInQueue = i;
            break;
        }
        i++;
    }

    if (positionInQueue < 0) {
        // Theoretically not possible.
        throw new RuntimeException("Created node (" + placeInLine + ") not found in getChildren().");
    }

    String placeBeforeUs;
    if (positionInQueue == 0) {
        // Lowest number in the queue, go for the lock.
        if (grabTicket(zookeeper, lockNode, LOCKING_TICKET)) {
            releaseTicket(zookeeper, lockNode, placeInLine);
            return LOCKING_TICKET;
        } else {
            placeBeforeUs = LOCKING_TICKET;
        }
    } else {
        // We are not in front of the queue, so we keep an eye on the znode right in front of us. When it is
        // deleted, that means it has reached the front of the queue, acquired the lock, did its business,
        // and released the lock.
        placeBeforeUs = children.get(positionInQueue - 1);
    }

    final CountDownLatch latch = new CountDownLatch(1);
    Stat stat = zookeeper.exists(lockNode + "/" + placeBeforeUs, new Watcher() {
        @Override
        public void process(WatchedEvent event) {
            // If *anything* changes, reevaluate out position in the queue.
            latch.countDown();
        }
    });

    // If stat is null, the znode in front of use got deleted during our inspection of the queue. If that happens,
    // simply reevaluate our position in the queue again. If there *is* a znode in front of us,
    // watch it for changes:
    if (stat != null) {
        logger.debug("Watching place in queue before us ({})", placeBeforeUs);
        latch.await();
    }

    return waitInLine(zookeeper, lockNode, placeInLine);
}

---

From source file:org.lable.oss.uniqueid.zookeeper.ResourceClaim.java

License:Apache License

/**
 * Try to claim an available resource from the resource pool.
 *
 * @param zookeeper ZooKeeper connection to use.
 * @param poolNode Path to the znode representing the resource pool.
 * @param poolSize Size of the resource pool.
 * @return The claimed resource.//from ww  w.j av  a 2 s. c o  m
 * @throws KeeperException
 * @throws InterruptedException
 */
static int claimResource(ZooKeeper zookeeper, String poolNode, int poolSize)
        throws KeeperException, InterruptedException {

    logger.debug("Trying to claim a resource.");
    List<String> claimedResources = zookeeper.getChildren(poolNode, false);
    if (claimedResources.size() >= poolSize) {
        logger.debug("No resources available at the moment (poolsize: {}), waiting.", poolSize);
        // No resources available. Wait for a resource to become available.
        final CountDownLatch latch = new CountDownLatch(1);
        zookeeper.getChildren(poolNode, new Watcher() {
            @Override
            public void process(WatchedEvent event) {
                latch.countDown();
            }
        });
        latch.await();
        return claimResource(zookeeper, poolNode, poolSize);
    }

    // Try to claim an available resource.
    for (int i = 0; i < poolSize; i++) {
        String resourcePath = Integer.toString(i);
        if (!claimedResources.contains(resourcePath)) {
            try {
                logger.debug("Trying to claim seemingly available resource {}.", resourcePath);
                zookeeper.create(poolNode + "/" + resourcePath, new byte[0], ZooDefs.Ids.OPEN_ACL_UNSAFE,
                        CreateMode.EPHEMERAL);
            } catch (KeeperException e) {
                if (e.code() == KeeperException.Code.NODEEXISTS) {
                    // Failed to claim this resource for some reason.
                    continue;
                } else {
                    // Unexpected failure.
                    throw e;
                }
            }
            logger.debug("Successfully claimed resource {}.", resourcePath);
            return i;
        }
    }

    return claimResource(zookeeper, poolNode, poolSize);
}

---

From source file:org.lable.oss.uniqueid.zookeeper.ZooKeeperInstance.java

License:Apache License

@Override
protected void before() throws Throwable {
    tempFolder = createTempDir();/*  w  ww  .  ja  v a2s .co m*/
    String zookeeperHost = "localhost:" + serverPort;
    ServerConfig config = new ServerConfig();
    config.parse(new String[] { serverPort, tempFolder.getAbsolutePath() });

    zkThread = new ZooKeeperThread(config);
    new Thread(zkThread).start();

    final CountDownLatch latch = new CountDownLatch(1);

    // Connect to the quorum and wait for the successful connection callback.
    zookeeper = new ZooKeeper(zookeeperHost, (int) TimeUnit.SECONDS.toMillis(10), new Watcher() {
        @Override
        public void process(WatchedEvent watchedEvent) {
            if (watchedEvent.getState() == Event.KeeperState.SyncConnected) {
                // Signal that the Zookeeper connection is established.
                latch.countDown();
            }
        }
    });

    // Wait for the connection to be established.
    boolean successfullyConnected = latch.await(12, TimeUnit.SECONDS);
    if (!successfullyConnected) {
        tempFolder.delete();
        throw new Exception("Could not start a local ZooKeeper quorum for testing.");
    }
}

---

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