Package org.apache.curator.framework.recipes.nodes

Class PersistentNode

java.lang.Object

org.apache.curator.framework.recipes.nodes.PersistentNode

All Implemented Interfaces:

Closeable, AutoCloseable

Direct Known Subclasses:

PersistentEphemeralNode

public class PersistentNode
extends Object
implements Closeable

A persistent node is a node that attempts to stay present in ZooKeeper, even through connection and session interruptions.

Thanks to bbeck (https://github.com/bbeck) for the initial coding and design

Constructor Summary

Constructors

Constructor	Description
PersistentNode(CuratorFramework givenClient, org.apache.zookeeper.CreateMode mode, boolean useProtection, String basePath, byte[] initData)
PersistentNode(CuratorFramework givenClient, org.apache.zookeeper.CreateMode mode, boolean useProtection, String basePath, byte[] initData, boolean useParentCreation)
PersistentNode(CuratorFramework givenClient, org.apache.zookeeper.CreateMode mode, boolean useProtection, String basePath, byte[] initData, long ttl, boolean useParentCreation)

Method Summary

Modifier and Type	Method	Description
void	close()
protected void	deleteNode()
String	getActualPath()	Returns the currently set path or null if the node does not exist
byte[]	getData()	Return the current value of our data
Listenable<PersistentNodeListener>	getListenable()	Returns the listenable
void	setData(byte[] data)	Set data that node should set in ZK also writes the data to the node.
void	start()	You must call start() to initiate the persistent node.
boolean	waitForInitialCreate(long timeout, TimeUnit unit)	Block until the either initial node creation initiated by start() succeeds or the timeout elapses.

Methods inherited from class java.lang.Object

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

Constructor Details

PersistentNode

public PersistentNode(CuratorFramework givenClient,
 org.apache.zookeeper.CreateMode mode,
 boolean useProtection,
 String basePath,
 byte[] initData)

Parameters:

givenClient - client instance

mode - creation mode

useProtection - if true, call CreateBuilderMain.withProtection()

basePath - the base path for the node

initData - data for the node

PersistentNode

public PersistentNode(CuratorFramework givenClient,
 org.apache.zookeeper.CreateMode mode,
 boolean useProtection,
 String basePath,
 byte[] initData,
 boolean useParentCreation)

Parameters:

givenClient - client instance

mode - creation mode

useProtection - if true, call CreateBuilderMain.withProtection()

basePath - the base path for the node

initData - data for the node

useParentCreation - if true, call CreateBuilderMain.creatingParentContainersIfNeeded()

PersistentNode

public PersistentNode(CuratorFramework givenClient,
 org.apache.zookeeper.CreateMode mode,
 boolean useProtection,
 String basePath,
 byte[] initData,
 long ttl,
 boolean useParentCreation)

Parameters:

givenClient - client instance

mode - creation mode

useProtection - if true, call CreateBuilderMain.withProtection()

basePath - the base path for the node

initData - data for the node

ttl - for ttl modes, the ttl to use

useParentCreation - if true, call CreateBuilderMain.creatingParentContainersIfNeeded()

Method Details

start

public void start()

You must call start() to initiate the persistent node. An attempt to create the node in the background will be started

waitForInitialCreate

public boolean waitForInitialCreate(long timeout,
 TimeUnit unit)
                             throws InterruptedException

Block until the either initial node creation initiated by start() succeeds or the timeout elapses.

Parameters:

timeout - the maximum time to wait

unit - time unit

Returns:

if the node was created before timeout

Throws:

InterruptedException - if the thread is interrupted

close

public void close()
           throws IOException

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Throws:

IOException

getListenable

public Listenable<PersistentNodeListener> getListenable()

Returns the listenable

Returns:

listenable

getActualPath

public String getActualPath()

Returns the currently set path or null if the node does not exist

Returns:

node path or null

setData

public void setData(byte[] data)
             throws Exception

Set data that node should set in ZK also writes the data to the node. NOTE: it is an error to call this method after start() but before the initial create has completed. Use waitForInitialCreate(long, TimeUnit) to ensure initial creation.

Parameters:

data - new data value

Throws:

Exception - errors

getData

public byte[] getData()

Return the current value of our data

Returns:

our data

deleteNode

protected void deleteNode()
                   throws Exception

Throws:

Exception