org.apache.solr.cloud
Class DistributedQueue

java.lang.Object
  org.apache.solr.cloud.DistributedQueue

public class DistributedQueue
extends Object

A distributed queue from zk recipes.

Constructor Summary

DistributedQueue(org.apache.zookeeper.ZooKeeper zookeeper, String dir, List<org.apache.zookeeper.data.ACL> acl)

Method Summary

byte[]	element() Return the head of the queue without modifying the queue.
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[]	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

DistributedQueue

public DistributedQueue(org.apache.zookeeper.ZooKeeper zookeeper,
                        String dir,
                        List<org.apache.zookeeper.data.ACL> acl)

Method Detail

element

public byte[] element()
               throws NoSuchElementException,
                      org.apache.zookeeper.KeeperException,
                      InterruptedException

Return the head of the queue without modifying the queue.

Returns:

the data at the head of the queue.

Throws:

NoSuchElementException

org.apache.zookeeper.KeeperException

InterruptedException

remove

public byte[] remove()
              throws NoSuchElementException,
                     org.apache.zookeeper.KeeperException,
                     InterruptedException

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

Returns:

The former head of the queue

Throws:

NoSuchElementException

org.apache.zookeeper.KeeperException

InterruptedException

take

public byte[] take()
            throws org.apache.zookeeper.KeeperException,
                   InterruptedException

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

Returns:

The former head of the queue

Throws:

NoSuchElementException

org.apache.zookeeper.KeeperException

InterruptedException

offer

public boolean offer(byte[] data)
              throws org.apache.zookeeper.KeeperException,
                     InterruptedException

Inserts data into queue.

Parameters:

data -

Returns:

true if data was successfully added

Throws:

org.apache.zookeeper.KeeperException

InterruptedException

peek

public byte[] peek()
            throws org.apache.zookeeper.KeeperException,
                   InterruptedException

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:

org.apache.zookeeper.KeeperException

InterruptedException

poll

public byte[] poll()
            throws org.apache.zookeeper.KeeperException,
                   InterruptedException

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:

org.apache.zookeeper.KeeperException

InterruptedException