org.apache.zookeeper

Class ZKUtil

java.lang.Object

org.apache.zookeeper.ZKUtil

public class ZKUtil
extends Object

Constructor Summary

Constructors

Constructor and Description
ZKUtil()

Method Summary

Modifier and Type	Method and Description
static void	deleteRecursive(ZooKeeper zk, String pathRoot) Recursively delete the node with the given path.
static void	deleteRecursive(ZooKeeper zk, String pathRoot, AsyncCallback.VoidCallback cb, Object ctx) Recursively delete the node with the given path.
static List<String>	listSubTreeBFS(ZooKeeper zk, String pathRoot) BFS Traversal of the system under pathRoot, with the entries in the list, in the same order as that of the traversal.
static void	visitSubTreeDFS(ZooKeeper zk, String path, boolean watch, AsyncCallback.StringCallback cb) Visits the subtree with root as given path and calls the passed callback with each znode found during the search.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ZKUtil

public ZKUtil()

Method Detail

deleteRecursive

public static void deleteRecursive(ZooKeeper zk,
                                   String pathRoot)
                            throws InterruptedException,
                                   KeeperException

Recursively delete the node with the given path.

Important: All versions, of all nodes, under the given node are deleted.

If there is an error with deleting one of the sub-nodes in the tree, this operation would abort and would be the responsibility of the app to handle the same. See #delete(String, int) for more details.

Throws:

IllegalArgumentException - if an invalid path is specified

InterruptedException

KeeperException

deleteRecursive

public static void deleteRecursive(ZooKeeper zk,
                                   String pathRoot,
                                   AsyncCallback.VoidCallback cb,
                                   Object ctx)
                            throws InterruptedException,
                                   KeeperException

Recursively delete the node with the given path. (async version).

Important: All versions, of all nodes, under the given node are deleted.

If there is an error with deleting one of the sub-nodes in the tree, this operation would abort and would be the responsibility of the app to handle the same.

Parameters:

zk - the zookeeper handle

pathRoot - the path to be deleted

cb - call back method

ctx - the context the callback method is called with

Throws:

IllegalArgumentException - if an invalid path is specified

InterruptedException

KeeperException

listSubTreeBFS

public static List<String> listSubTreeBFS(ZooKeeper zk,
                                          String pathRoot)
                                   throws KeeperException,
                                          InterruptedException

BFS Traversal of the system under pathRoot, with the entries in the list, in the same order as that of the traversal.

Important: This is not an atomic snapshot of the tree ever, but the state as it exists across multiple RPCs from zkClient to the ensemble. For practical purposes, it is suggested to bring the clients to the ensemble down (i.e. prevent writes to pathRoot) to 'simulate' a snapshot behavior.

Parameters:

zk - the zookeeper handle

pathRoot - The znode path, for which the entire subtree needs to be listed.

Throws:

InterruptedException

KeeperException

visitSubTreeDFS

public static void visitSubTreeDFS(ZooKeeper zk,
                                   String path,
                                   boolean watch,
                                   AsyncCallback.StringCallback cb)
                            throws KeeperException,
                                   InterruptedException

Visits the subtree with root as given path and calls the passed callback with each znode found during the search. It performs a depth-first, pre-order traversal of the tree.

Important: This is not an atomic snapshot of the tree ever, but the state as it exists across multiple RPCs from zkClient to the ensemble. For practical purposes, it is suggested to bring the clients to the ensemble down (i.e. prevent writes to pathRoot) to 'simulate' a snapshot behavior.

Throws:

KeeperException

InterruptedException