org.eclipse.smila.zookeeper
Class ZkConnection

java.lang.Object
  org.eclipse.smila.zookeeper.ZkConnection

public class ZkConnection
extends java.lang.Object

wrapper of ZooKeeper client that executes a number of ZooKeeper operation with handling for ConnectionLoss errors.

Field Summary

static byte[]

NO_DATA use this constant for the data argument to create empty nodes.

Constructor Summary

ZkConnection(ZooKeeperService service)
create instance using the given service to get ZooKeeper clients when needed.

Method Summary

void	createNode(java.lang.String nodePath, byte[] data) create a persistent node with given data.
void	createNode(java.lang.String nodePath, byte[] data, CreateMode mode) create a node with given data.
void	createPath(java.lang.String nodePath, byte[] data) create a persistent node with given data.
void	deleteNode(java.lang.String nodePath) delete the given node.
void	deleteTree(java.lang.String nodePath) delete a complete node subtree, starting from the given path.
void	disconnectZkSession() Close current zookeeper client (session).
void	ensurePathExists(java.lang.String path)
Stat	exists(java.lang.String nodePath) Check if node exists.
Stat	exists(java.lang.String nodePath, Watcher watcher) Check if node exists and set a watcher.
java.util.List<java.lang.String>	getChildrenSorted(java.lang.String nodePath) get children from node, sorted by name.
byte[]	getData(java.lang.String nodePath) get data of node.
byte[]	getData(java.lang.String nodePath, Stat stat) get data and stat of node.
long	getSessionId()
Stat	setData(java.lang.String nodePath, byte[] nodeData) update data on existing node.
Stat	setData(java.lang.String nodePath, byte[] nodeData, int version) update data on existing node if version does match.

Methods inherited from class java.lang.Object

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

Field Detail

NO_DATA

public static final byte[] NO_DATA

use this constant for the data argument to create empty nodes.

Constructor Detail

ZkConnection

public ZkConnection(ZooKeeperService service)

create instance using the given service to get ZooKeeper clients when needed.

Parameters:

service - ZooKeeper service.

Method Detail

getSessionId

public long getSessionId()

Returns:

sessionId of underlying zookeeper client.

createNode

public void createNode(java.lang.String nodePath,
                       byte[] data)
                throws KeeperException

create a persistent node with given data. fails if the parent node of the given path does not exist.

Parameters:

nodePath - path for node to create

data - data of node to create

Throws:

KeeperException - error

createNode

public void createNode(java.lang.String nodePath,
                       byte[] data,
                       CreateMode mode)
                throws KeeperException

create a node with given data. fails if the parent node of the given path does not exist.

Parameters:

nodePath - path for node to create

data - data of node to create

mode - 'PERSISTENT' if we want a persistent node, 'EPHEMERAL' if we want an ephemeral node

Throws:

KeeperException - error

createPath

public void createPath(java.lang.String nodePath,
                       byte[] data)
                throws KeeperException

create a persistent node with given data. creates the complete hierarchy if necessary.

Parameters:

nodePath - path for node to create

data - data of node to create

Throws:

KeeperException - error

ensurePathExists

public void ensurePathExists(java.lang.String path)
                      throws KeeperException

Parameters:

path - the path whose elements should be created as zookeeper nodes if not existent

Throws:

KeeperException - error creating zookeeper nodes

deleteNode

public void deleteNode(java.lang.String nodePath)
                throws KeeperException

delete the given node.

Parameters:

nodePath - path for node to delete

Throws:

KeeperException - KeeperException.NoNodeException if node doesn't exist

deleteTree

public void deleteTree(java.lang.String nodePath)
                throws KeeperException

delete a complete node subtree, starting from the given path.

Parameters:

nodePath - root node of tree to delete

Throws:

KeeperException - error deleting tree. State of subtree is quite undefined afterwards.

exists

public Stat exists(java.lang.String nodePath)
            throws KeeperException

Check if node exists.

Parameters:

nodePath - path for node to check existence

Returns:

Stat of node to exist, 'null' if no such node exists.

Throws:

KeeperException - error

exists

public Stat exists(java.lang.String nodePath,
                   Watcher watcher)
            throws KeeperException

Check if node exists and set a watcher.

Parameters:

nodePath - path for node to check existence

Returns:

Stat of node to exist, 'null' if no such node exists.

Throws:

KeeperException - error

setData

public Stat setData(java.lang.String nodePath,
                    byte[] nodeData,
                    int version)
             throws KeeperException

update data on existing node if version does match.

Parameters:

nodePath - path for node to update data

nodeData - new data

version - the expected matching version

Throws:

KeeperException - KeeperException.NoNodeException if node doesn't exist

setData

public Stat setData(java.lang.String nodePath,
                    byte[] nodeData)
             throws KeeperException

update data on existing node.

Parameters:

nodePath - path for node to update data

nodeData - new data

Throws:

KeeperException - KeeperException.NoNodeException if node doesn't exist

getData

public byte[] getData(java.lang.String nodePath)
               throws KeeperException

get data of node.

Parameters:

nodePath - the node path to get the data

Returns:

node data

Throws:

KeeperException - KeeperException.NoNodeException if node doesn't exist

getData

public byte[] getData(java.lang.String nodePath,
                      Stat stat)
               throws KeeperException

get data and stat of node.

Parameters:

nodePath - the node path to get the data

stat - contains the stat of the node after the call

Returns:

node data

Throws:

KeeperException - KeeperException.NoNodeException if node doesn't exist

getChildrenSorted

public java.util.List<java.lang.String> getChildrenSorted(java.lang.String nodePath)
                                                   throws KeeperException

get children from node, sorted by name.

Parameters:

nodePath - path of node to get the children

Returns:

sorted list of children

Throws:

KeeperException - KeeperException.NoNodeException if node doesn't exist

disconnectZkSession

public void disconnectZkSession()
                         throws java.io.IOException,
                                ClusterConfigException

Close current zookeeper client (session).

Throws:

java.io.IOException

ClusterConfigException