Example usage for org.apache.zookeeper ZooKeeper transaction

Introduction

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

Prototype

public Transaction transaction() 

Source Link

Document

A Transaction is a thin wrapper on the #multi method which provides a builder object that can be used to construct and commit an atomic set of operations.

Usage

From source file:org.apache.bookkeeper.zookeeper.BkZooKeeperClient.java

License:Apache License

@Override
@Deprecated//  w  w  w. ja v a  2  s  .c  o m
public Transaction transaction() {
    // since there is no reference about which client that the transaction could use
    // so just use ZooKeeper instance directly.
    // you'd better to use {@link #multi}.
    ZooKeeper zkHandle = zk.get();
    if (null == zkHandle) {
        return super.transaction();
    }
    return zkHandle.transaction();
}

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From source file:org.apache.distributedlog.service.placement.ZKPlacementStateManager.java

License:Apache License

@Override
public void saveOwnership(TreeSet<ServerLoad> serverLoads) throws StateManagerSaveException {
    logger.info("saving ownership");
    try {//  w  w w.ja v a2  s . c  o  m
        ZooKeeper zk = zkClient.get();
        // use timestamp as data so watchers will see any changes
        byte[] timestamp = ByteBuffer.allocate(8).putLong(System.currentTimeMillis()).array();

        if (zk.exists(serverLoadPath, false) == null) { //create path to rootnode if it does not yet exist
            createServerLoadPathIfNoExists(timestamp);
        }

        Transaction tx = zk.transaction();
        List<String> children = zk.getChildren(serverLoadPath, false);
        HashSet<String> servers = new HashSet<String>(children);
        tx.setData(serverLoadPath, timestamp, -1); // trigger the watcher that data has been updated
        for (ServerLoad serverLoad : serverLoads) {
            String server = serverToZkFormat(serverLoad.getServer());
            String serverPath = serverPath(server);
            if (servers.contains(server)) {
                servers.remove(server);
                tx.setData(serverPath, serverLoad.serialize(), -1);
            } else {
                tx.create(serverPath, serverLoad.serialize(), zkClient.getDefaultACL(), CreateMode.PERSISTENT);
            }
        }
        for (String server : servers) {
            tx.delete(serverPath(server), -1);
        }
        tx.commit();
    } catch (InterruptedException | IOException | KeeperException e) {
        throw new StateManagerSaveException(e);
    }
}

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