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