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 and Description
PersistentNode(org.apache.curator.framework.CuratorFramework client, org.apache.zookeeper.CreateMode mode, boolean useProtection, String basePath, byte[] initData)

Method Summary

Modifier and Type	Method and Description
void	close()
String	getActualPath() Returns the currently set path or null if the node does not exist
byte[]	getData() Return the current value of our data
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 Detail

PersistentNode

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

Parameters:

client - client instance

mode - creation mode

useProtection - if true, call CreateBuilder.withProtection()

basePath - the base path for the node

initData - data for the node

Method Detail

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 Closeable

Specified by:

close in interface AutoCloseable

Throws:

IOException

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