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.example.directorio.ZooKeeperMannager.java

public String getData(String path2) throws InterruptedException, KeeperException, UnsupportedEncodingException {
    final String path = path2;
    Stat stat = znode_exists(path);//from  ww w.  j av  a2  s. c o m

    byte[] b = null;
    if (stat != null) {
        b = zk.getData(path, new Watcher() {
            public void process(WatchedEvent we) {
                if (we.getType() == Event.EventType.None) {
                    switch (we.getState()) {
                    case Expired:
                        zkConnection.getConnectedSignal().countDown();
                        break;
                    }

                } else {
                    try {
                        byte[] bn = zk.getData(path, false, null);
                        String data = new String(bn, "UTF-8");
                        System.out.println(data);
                        zkConnection.getConnectedSignal().countDown();

                    } catch (Exception ex) {
                        ex.printStackTrace();
                    }
                }
            }
        }, null);

        String data = new String(b, "UTF-8");
        //System.out.println(data);
        zkConnection.getConnectedSignal().await();

    } else {
        System.out.println("Node does not exists");
    }
    return new String(b);
}

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From source file:com.facebook.infrastructure.service.StorageService.java

License:Apache License

private void reportToZookeeper() throws Throwable {
    try {/*from ww w .  ja  v a  2  s.c  o  m*/
        zk_ = new ZooKeeper(DatabaseDescriptor.getZkAddress(), DatabaseDescriptor.getZkSessionTimeout(),
                new Watcher() {
                    public void process(WatchedEvent we) {
                        String path = "/Cassandra/" + DatabaseDescriptor.getClusterName() + "/Leader";
                        String eventPath = we.getPath();
                        logger_.debug("PROCESS EVENT : " + eventPath);
                        if (eventPath != null && (eventPath.indexOf(path) != -1)) {
                            logger_.debug("Signalling the leader instance ...");
                            LeaderElector.instance().signal();
                        }
                    }
                });

        Stat stat = zk_.exists("/", false);
        if (stat != null) {
            stat = zk_.exists("/Cassandra", false);
            if (stat == null) {
                logger_.debug("Creating the Cassandra znode ...");
                zk_.create("/Cassandra", new byte[0], Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
            }

            String path = "/Cassandra/" + DatabaseDescriptor.getClusterName();
            stat = zk_.exists(path, false);
            if (stat == null) {
                logger_.debug("Creating the cluster znode " + path);
                zk_.create(path, new byte[0], Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
            }

            /* Create the Leader, Locks and Misc znode */
            stat = zk_.exists(path + "/Leader", false);
            if (stat == null) {
                logger_.debug("Creating the leader znode " + path);
                zk_.create(path + "/Leader", new byte[0], Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
            }

            stat = zk_.exists(path + "/Locks", false);
            if (stat == null) {
                logger_.debug("Creating the locks znode " + path);
                zk_.create(path + "/Locks", new byte[0], Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
            }

            stat = zk_.exists(path + "/Misc", false);
            if (stat == null) {
                logger_.debug("Creating the misc znode " + path);
                zk_.create(path + "/Misc", new byte[0], Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
            }
        }
    } catch (KeeperException ke) {
        LogUtil.throwableToString(ke);
        /* do the re-initialize again. */
        reportToZookeeper();
    }
}

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From source file:com.facebook.zookeeper.convenience.ZkQuickConnection.java

License:Apache License

private ZkQuickConnection(ZooKeeperFactory zooKeeperFactory, int connectionTimeoutMillis)
        throws IOException, InterruptedException, TimeoutException {
    final CountDownLatch latch = new CountDownLatch(1);
    zk = zooKeeperFactory.create(new Watcher() {
        @Override/*from  ww  w. j  ava 2 s.co m*/
        public void process(WatchedEvent event) {
            if (event.getState() == Watcher.Event.KeeperState.SyncConnected) {
                latch.countDown();
            }
        }
    });
    if (!latch.await(connectionTimeoutMillis, TimeUnit.MILLISECONDS)) {
        zk.close();
        throw new TimeoutException("Failed to connect to ZooKeeper");
    }
}

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From source file:com.facebook.zookeeper.mock.MockZkConnectionManager.java

License:Apache License

public void refreshClient() {
    try {//from  ww  w . j av a 2 s  . c o m
        if (zk != null) {
            zk.close();
        }
        zk = zooKeeperFactory.create(new Watcher() {
            @Override
            public void process(WatchedEvent event) {
                for (Watcher watcher : watchers) {
                    watcher.process(event);
                }
            }
        });
    } catch (Exception e) {
        throw new RuntimeException(e);
    }
}

---

From source file:com.github.mosuka.zookeeper.nicli.util.ZooKeeperConnection.java

License:Apache License

public void connect(String server, int timeout) throws IOException, InterruptedException {
    zookeeper = new ZooKeeper(server, timeout, new Watcher() {
        public void process(WatchedEvent event) {
            if (event.getState() == KeeperState.SyncConnected) {
                connSignal.countDown();//from   w  w w  .  j  a v  a  2s. c  o  m
            }
        }
    });
    connSignal.await();
}

---

From source file:com.glaf.cluster.catalina.session.ZooKeeperClientImpl.java

License:Apache License

protected void doStart() {
    try {//  w ww .j  a  v  a  2s .  c o  m
        final Watcher watcher = new Watcher() {
            @Override
            public void process(WatchedEvent event) {
                switch (event.getState()) {
                case Expired:
                    resetSession();
                    break;
                case SyncConnected:
                    notifySessionConnected();
                    break;
                case Disconnected:
                    notifySessionDisconnected();
                    break;
                default:
                    break;
                }
            }
        };
        zooKeeper = zooKeeperFactory.newZooKeeper(watcher);
        createPersistentNode(GROUP_NAME);
    } catch (InterruptedException e) {
        throw new RuntimeException("Cannot start ZooKeeper client", e);
    }
}

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From source file:com.glaf.cluster.catalina.session.ZooKeeperClientImpl.java

License:Apache License

public Set<String> listNodes(final String path, final NodeListChangedListener nodeListChangedListener)
        throws InterruptedException {
    Set<String> res = new HashSet<String>();
    final Watcher watcher = (nodeListChangedListener != null) ? new Watcher() {
        @Override/*www. java  2  s. c  om*/
        public void process(WatchedEvent event) {
            if (event.getType() == Watcher.Event.EventType.NodeChildrenChanged) {
                nodeListChangedListener.onNodeListChanged();
            }
        }
    } : null;
    try {
        List<String> children = zooKeeperCall("Cannot list nodes", new Callable<List<String>>() {
            @Override
            public List<String> call() throws Exception {
                return zooKeeper.getChildren(path, watcher);
            }
        });

        if (children == null) {
            return null;
        }
        for (String childPath : children) {
            res.add(extractLastPart(childPath));
        }
        return res;
    } catch (KeeperException e) {
        throw new RuntimeException("Cannot list nodes", e);
    }
}

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From source file:com.glaf.cluster.catalina.session.ZooKeeperClientImpl.java

License:Apache License

private Watcher wrapNodeListener(final NodeListener nodeListener) {
    if (nodeListener != null) {
        return new Watcher() {
            @Override/*from   w  ww . jav a  2  s  .c o m*/
            public void process(WatchedEvent event) {
                switch (event.getType()) {
                case NodeCreated:
                    nodeListener.onNodeCreated(event.getPath());
                    break;
                case NodeDeleted:
                    nodeListener.onNodeDeleted(event.getPath());
                    break;
                case NodeDataChanged:
                    nodeListener.onNodeDataChanged(event.getPath());
                    break;
                default:
                    break;
                }
            }
        };
    } else {
        return null;
    }
}

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From source file:com.glaf.cluster.catalina.session.ZooKeeperFactory.java

License:Apache License

public ZooKeeper newZooKeeper() {
    return newZooKeeper(new Watcher() {
        @Override/*from ww w .  j a  va  2  s  .  c o  m*/
        public void process(WatchedEvent event) {
        }
    });
}

---

From source file:com.greplin.zookeeper.RobustZooKeeper.java

License:Apache License

private void lockRecipeStepTwo(final String fullPath, final String relativePath, final String lockName,
        final Runnable action) throws IOException, InterruptedException, KeeperException {

    log.info("Client " + clientNumber + " at start of lockRecipeStepTwo with relativePath = " + relativePath);
    if (shutdown.get()) {
        log.warn("Client " + clientNumber + " is shutdown - so I'm going to give up my attempt to lock");
        return;/*from w w  w. j  av  a 2s . c o m*/
    }

    // step 2
    final List<String> children = getClient().getChildren(getLockParent(lockName), false);
    assert children.size() > 0; // at the ver least, my node should be there.
    Collections.sort(children);

    // step 3
    if (relativePath.equals(children.get(0))) {
        log.info("Client " + clientNumber + " has the lowest number lock attempt (" + relativePath
                + "), so it holds the lock");
        try {
            action.run();
        } finally {
            log.info("Client " + clientNumber + " finished doing my work with " + relativePath
                    + ", so I'm giving up the lock.");
            try {
                getClient().delete(fullPath, -1);
            } catch (KeeperException.NoNodeException e) {
                log.warn("After I finished running an action with lock " + lockName + " the actions lock node ("
                        + fullPath + ") no longer exists. This should only happen if you manually deleted "
                        + fullPath + " or there was an underlying network failure, and we had to reconnect");
            }
        }
        return;
    }

    // step 4
    final int indexOfNodeBefore = children.indexOf(relativePath) - 1;
    if (indexOfNodeBefore < 0) {
        throw new IllegalStateException(
                "indexOfNodeBefore is " + indexOfNodeBefore + ", and children are: " + children);
    }

    final String nodeBeforeMine = children.get(indexOfNodeBefore);
    log.info("Client " + clientNumber + "  (at " + relativePath + ") is setting a watch on the node before me ("
            + nodeBeforeMine + ")");
    final Stat exists = getClient().exists(getLockParent(lockName) + "/" + nodeBeforeMine, new Watcher() {
        @Override
        public void process(WatchedEvent event) {
            try {
                log.info("Client " + clientNumber + ", when watching " + nodeBeforeMine + ", got notified: "
                        + event);
                lockRecipeStepTwo(fullPath, relativePath, lockName, action);
            } catch (Exception e) {
                log.warn("Unable to execute action with lock " + lockName, e);
            }
        }
    });

    // step 5
    if (exists == null) {
        log.info("Client " + clientNumber + " expected " + nodeBeforeMine
                + " to exist - but it doesn't so re-running step 2");
        lockRecipeStepTwo(fullPath, relativePath, lockName, action);
    }
}

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