com.netflix.curator.framework.recipes.queue
Class DistributedQueue<T>

java.lang.Object
  com.netflix.curator.framework.recipes.queue.DistributedQueue<T>

All Implemented Interfaces:

Closeable

public class DistributedQueue<T>
extends Object
implements Closeable

An implementation of the Distributed Queue ZK recipe. Items put into the queue are guaranteed to be ordered (by means of ZK's PERSISTENT_SEQUENTIAL node).

Guarantees:

If a single consumer takes items out of the queue, they will be ordered FIFO. i.e. if ordering is important, use a LeaderSelector to nominate a single consumer.

Unless a QueueBuilder.lockPath(String) is used, there is only guaranteed processing of each message to the point of receipt by a given instance. If an instance receives an item from the queue but dies while processing it, the item will be lost. If you need message recoverability, use a QueueBuilder.lockPath(String)

Method Summary

void	close()
boolean	flushPuts(long waitTime, TimeUnit timeUnit) Wait until any pending puts are committed
void	put(T item) Add an item into the queue.
void	putMulti(MultiItem<T> items) Add a set of items into the queue.
void	setErrorMode(ErrorMode newErrorMode) Used when the queue is created with a QueueBuilder.lockPath(String).
void	start() Start the queue.

Methods inherited from class java.lang.Object

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

Method Detail

start

public void start()
           throws Exception

Start the queue. No other methods work until this is called

Throws:

Exception - startup errors

setErrorMode

public void setErrorMode(ErrorMode newErrorMode)

Used when the queue is created with a QueueBuilder.lockPath(String). Determines the behavior when the queue consumer throws an exception

Parameters:

newErrorMode - the new error mode (the default is ErrorMode.REQUEUE

flushPuts

public boolean flushPuts(long waitTime,
                         TimeUnit timeUnit)
                  throws InterruptedException

Wait until any pending puts are committed

Parameters:

waitTime - max wait time

timeUnit - time unit

Returns:

true if the flush was successful, false if it timed out first

Throws:

InterruptedException - if thread was interrupted

close

public void close()
           throws IOException

Specified by:

close in interface Closeable

Throws:

IOException

put

public void put(T item)
         throws Exception

Add an item into the queue. Adding is done in the background - thus, this method will return quickly.

Parameters:

item - item to add

Throws:

Exception - connection issues

putMulti

public void putMulti(MultiItem<T> items)
              throws Exception

Add a set of items into the queue. Adding is done in the background - thus, this method will return quickly.

Parameters:

items - items to add

Throws:

Exception - connection issues