Package org.apache.curator.framework.recipes.queue

Class SimpleDistributedQueue

java.lang.Object

org.apache.curator.framework.recipes.queue.SimpleDistributedQueue

public class SimpleDistributedQueue
extends java.lang.Object

Drop in replacement for: org.apache.zookeeper.recipes.queue.DistributedQueue that is part of the ZooKeeper distribution

This class is data compatible with the ZK version. i.e. it uses the same naming scheme so it can read from an existing queue

Constructor Summary

Constructors

Constructor	Description
SimpleDistributedQueue(org.apache.curator.framework.CuratorFramework client, java.lang.String path)

Method Summary

Modifier and Type	Method	Description
byte[]	element()	Return the head of the queue without modifying the queue.
protected void	ensurePath()
boolean	offer(byte[] data)	Inserts data into queue.
byte[]	peek()	Returns the data at the first element of the queue, or null if the queue is empty.
byte[]	poll()	Attempts to remove the head of the queue and return it.
byte[]	poll(long timeout, java.util.concurrent.TimeUnit unit)	Retrieves and removes the head of this queue, waiting up to the specified wait time if necessary for an element to become available.
byte[]	remove()	Attempts to remove the head of the queue and return it.
byte[]	take()	Removes the head of the queue and returns it, blocks until it succeeds.

Methods inherited from class java.lang.Object

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

Constructor Detail

SimpleDistributedQueue

public SimpleDistributedQueue(org.apache.curator.framework.CuratorFramework client,
                              java.lang.String path)

Parameters:

client - the client

path - path to store queue nodes

Method Detail

element

public byte[] element()
               throws java.lang.Exception

Return the head of the queue without modifying the queue.

Returns:

the data at the head of the queue.

Throws:

java.lang.Exception - errors

java.util.NoSuchElementException - if the queue is empty

remove

public byte[] remove()
              throws java.lang.Exception

Attempts to remove the head of the queue and return it.

Returns:

The former head of the queue

Throws:

java.lang.Exception - errors

java.util.NoSuchElementException - if the queue is empty

take

public byte[] take()
            throws java.lang.Exception

Removes the head of the queue and returns it, blocks until it succeeds.

Returns:

The former head of the queue

Throws:

java.lang.Exception - errors

offer

public boolean offer(byte[] data)
              throws java.lang.Exception

Inserts data into queue.

Parameters:

data - the data

Returns:

true if data was successfully added

Throws:

java.lang.Exception - errors

peek

public byte[] peek()
            throws java.lang.Exception

Returns the data at the first element of the queue, or null if the queue is empty.

Returns:

data at the first element of the queue, or null.

Throws:

java.lang.Exception - errors

poll

public byte[] poll(long timeout,
                   java.util.concurrent.TimeUnit unit)
            throws java.lang.Exception

Retrieves and removes the head of this queue, waiting up to the specified wait time if necessary for an element to become available.

Parameters:

timeout - how long to wait before giving up, in units of unit

unit - a TimeUnit determining how to interpret the timeout parameter

Returns:

the head of this queue, or null if the specified waiting time elapses before an element is available

Throws:

java.lang.Exception - errors

poll

public byte[] poll()
            throws java.lang.Exception

Attempts to remove the head of the queue and return it. Returns null if the queue is empty.

Returns:

Head of the queue or null.

Throws:

java.lang.Exception - errors

ensurePath

protected void ensurePath()
                   throws java.lang.Exception

Throws:

java.lang.Exception