org.apache.curator.framework.recipes.queue
Class BlockingQueueConsumer<T>

java.lang.Object
  org.apache.curator.framework.recipes.queue.BlockingQueueConsumer<T>

All Implemented Interfaces:

QueueConsumer<T>, org.apache.curator.framework.state.ConnectionStateListener

public class BlockingQueueConsumer<T>
extends Object
implements QueueConsumer<T>

Utility - a queue consumer that provides behavior similar to a BlockingQueue

Constructor Summary

BlockingQueueConsumer(org.apache.curator.framework.state.ConnectionStateListener connectionStateListener)
Creates with capacity of Integer.MAX_VALUE

BlockingQueueConsumer(org.apache.curator.framework.state.ConnectionStateListener connectionStateListener, BlockingQueue<T> queue)
Wrap the given blocking queue

BlockingQueueConsumer(org.apache.curator.framework.state.ConnectionStateListener connectionStateListener, int capacity)

Method Summary

void	consumeMessage(T message) Process a message from the queue
int	drainTo(Collection<? super T> c) Removes all available elements from this queue and adds them to the given collection.
List<T>	getItems() Return any currently queued items without removing them from the queue
int	size() Returns the number of currently queue items
void	stateChanged(org.apache.curator.framework.CuratorFramework client, org.apache.curator.framework.state.ConnectionState newState)
T	take() Take the next item from the queue, blocking until there is an item available
T	take(int time, TimeUnit unit) Take the next item from the queue, waiting up to the specified time for an available item.

Methods inherited from class java.lang.Object

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

Constructor Detail

BlockingQueueConsumer

public BlockingQueueConsumer(org.apache.curator.framework.state.ConnectionStateListener connectionStateListener)

Creates with capacity of Integer.MAX_VALUE

Parameters:

connectionStateListener - listener for connection state changes

BlockingQueueConsumer

public BlockingQueueConsumer(org.apache.curator.framework.state.ConnectionStateListener connectionStateListener,
                             int capacity)

Parameters:

capacity - max capacity (i.e. puts block if full)

connectionStateListener - listener for connection state changes

BlockingQueueConsumer

public BlockingQueueConsumer(org.apache.curator.framework.state.ConnectionStateListener connectionStateListener,
                             BlockingQueue<T> queue)

Wrap the given blocking queue

Parameters:

queue - queue to use

connectionStateListener - listener for connection state changes

Method Detail

consumeMessage

public void consumeMessage(T message)
                    throws Exception

Description copied from interface: QueueConsumer

Process a message from the queue

Specified by:

consumeMessage in interface QueueConsumer<T>

Parameters:

message - message to process

Throws:

Exception - any errors

getItems

public List<T> getItems()

Return any currently queued items without removing them from the queue

Returns:

items (can be empty)

size

public int size()

Returns the number of currently queue items

Returns:

currently queue item count or 0

take

public T take()
       throws InterruptedException

Take the next item from the queue, blocking until there is an item available

Returns:

the item

Throws:

InterruptedException - thread interruption

take

public T take(int time,
              TimeUnit unit)
       throws InterruptedException

Take the next item from the queue, waiting up to the specified time for an available item. If the time elapses, null is returned.

Parameters:

time - amount of time to block

unit - time unit

Returns:

next item or null

Throws:

InterruptedException - thread interruption

drainTo

public int drainTo(Collection<? super T> c)

Removes all available elements from this queue and adds them to the given collection. This operation may be more efficient than repeatedly polling this queue. A failure encountered while attempting to add elements to collection c may result in elements being in neither, either or both collections when the associated exception is thrown. Attempts to drain a queue to itself result in IllegalArgumentException. Further, the behavior of this operation is undefined if the specified collection is modified while the operation is in progress.

Parameters:

c - the collection to transfer elements into

Returns:

the number of elements transferred

Throws:

UnsupportedOperationException - if addition of elements is not supported by the specified collection

ClassCastException - if the class of an element of this queue prevents it from being added to the specified collection

NullPointerException - if the specified collection is null

IllegalArgumentException - if the specified collection is this queue, or some property of an element of this queue prevents it from being added to the specified collection

stateChanged

public void stateChanged(org.apache.curator.framework.CuratorFramework client,
                         org.apache.curator.framework.state.ConnectionState newState)

Specified by:

stateChanged in interface org.apache.curator.framework.state.ConnectionStateListener