org.apache.zookeeper.util

Class CircularBlockingQueue<E>

java.lang.Object

org.apache.zookeeper.util.CircularBlockingQueue<E>

All Implemented Interfaces:

Iterable<E>, Collection<E>, BlockingQueue<E>, Queue<E>

public class CircularBlockingQueue<E>
extends Object
implements BlockingQueue<E>

A bounded blocking queue backed by an array. This queue orders elements FIFO (first-in-first-out). The head of the queue is that element that has been on the queue the longest time. The tail of the queue is that element that has been on the queue the shortest time. New elements are inserted at the tail of the queue, and the queue retrieval operations obtain elements at the head of the queue. If the queue is full, the head of the queue (the oldest element) will be removed to make room for the newest element.

Constructor Summary

Constructors

Constructor and Description
CircularBlockingQueue(int queueSize)

Method Summary

Modifier and Type	Method and Description
boolean	add(E e)
boolean	addAll(Collection<? extends E> arg0)
void	clear()
boolean	contains(Object o)
boolean	containsAll(Collection<?> arg0)
int	drainTo(Collection<? super E> c)
int	drainTo(Collection<? super E> c, int maxElements)
E	element()
long	getDroppedCount() Returns the number of elements that were dropped from the queue because the queue was full when a new element was offered.
boolean	isEmpty()
Iterator<E>	iterator()
boolean	offer(E e) This method differs from BlockingQueue.offer(Object) in that it will remove the oldest queued element (the element at the front of the queue) in order to make room for any new elements if the queue is full.
boolean	offer(E e, long timeout, TimeUnit unit)
E	peek()
E	poll()
E	poll(long timeout, TimeUnit unit)
void	put(E e)
int	remainingCapacity()
E	remove()
boolean	remove(Object o)
boolean	removeAll(Collection<?> arg0)
boolean	retainAll(Collection<?> arg0)
int	size()
E	take()
Object[]	toArray()
<T> T[]	toArray(T[] arg0)

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Collection

equals, hashCode, parallelStream, removeIf, spliterator, stream

Methods inherited from interface java.lang.Iterable

forEach

Constructor Detail

CircularBlockingQueue

public CircularBlockingQueue(int queueSize)

Method Detail

offer

public boolean offer(E e)

This method differs from BlockingQueue.offer(Object) in that it will remove the oldest queued element (the element at the front of the queue) in order to make room for any new elements if the queue is full.

Specified by:

offer in interface BlockingQueue<E>

Specified by:

offer in interface Queue<E>

Parameters:

e - the element to add

Returns:

true since it will make room for any new elements if required

poll

public E poll(long timeout,
              TimeUnit unit)
       throws InterruptedException

Specified by:

poll in interface BlockingQueue<E>

Throws:

InterruptedException

take

public E take()
       throws InterruptedException

Specified by:

take in interface BlockingQueue<E>

Throws:

InterruptedException

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in interface Collection<E>

size

public int size()

Specified by:

size in interface Collection<E>

getDroppedCount

public long getDroppedCount()

Returns the number of elements that were dropped from the queue because the queue was full when a new element was offered.

Returns:

The number of elements dropped (lost) from the queue

drainTo

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

Specified by:

drainTo in interface BlockingQueue<E>

poll

public E poll()

Specified by:

poll in interface Queue<E>

element

public E element()

Specified by:

element in interface Queue<E>

peek

public E peek()

Specified by:

peek in interface Queue<E>

remove

public E remove()

Specified by:

remove in interface Queue<E>

addAll

public boolean addAll(Collection<? extends E> arg0)

Specified by:

addAll in interface Collection<E>

clear

public void clear()

Specified by:

clear in interface Collection<E>

containsAll

public boolean containsAll(Collection<?> arg0)

Specified by:

containsAll in interface Collection<E>

iterator

public Iterator<E> iterator()

Specified by:

iterator in interface Iterable<E>

Specified by:

iterator in interface Collection<E>

removeAll

public boolean removeAll(Collection<?> arg0)

Specified by:

removeAll in interface Collection<E>

retainAll

public boolean retainAll(Collection<?> arg0)

Specified by:

retainAll in interface Collection<E>

toArray

public Object[] toArray()

Specified by:

toArray in interface Collection<E>

toArray

public <T> T[] toArray(T[] arg0)

Specified by:

toArray in interface Collection<E>

add

public boolean add(E e)

Specified by:

add in interface Collection<E>

Specified by:

add in interface BlockingQueue<E>

Specified by:

add in interface Queue<E>

contains

public boolean contains(Object o)

Specified by:

contains in interface Collection<E>

Specified by:

contains in interface BlockingQueue<E>

drainTo

public int drainTo(Collection<? super E> c,
                   int maxElements)

Specified by:

drainTo in interface BlockingQueue<E>

offer

public boolean offer(E e,
                     long timeout,
                     TimeUnit unit)
              throws InterruptedException

Specified by:

offer in interface BlockingQueue<E>

Throws:

InterruptedException

put

public void put(E e)
         throws InterruptedException

Specified by:

put in interface BlockingQueue<E>

Throws:

InterruptedException

remainingCapacity

public int remainingCapacity()

Specified by:

remainingCapacity in interface BlockingQueue<E>

remove

public boolean remove(Object o)

Specified by:

remove in interface Collection<E>

Specified by:

remove in interface BlockingQueue<E>