Package org.eclipse.jetty.util

Class ConcurrentArrayQueue<T>

java.lang.Object

java.util.AbstractCollection<E>

java.util.AbstractQueue<T>

org.eclipse.jetty.util.ConcurrentArrayQueue<T>

Type Parameters:

T - the Array entry type

All Implemented Interfaces:

Iterable<T>, Collection<T>, Queue<T>

public class ConcurrentArrayQueue<T>
extends AbstractQueue<T>

A concurrent, unbounded implementation of Queue that uses singly-linked array blocks to store elements.

This class is a drop-in replacement for ConcurrentLinkedQueue, with similar performance but producing less garbage because arrays are used to store elements rather than nodes.

The algorithm used is a variation of the algorithm from Gidenstam, Sundell and Tsigas (http://www.adm.hb.se/~AGD/Presentations/CacheAwareQueue_OPODIS.pdf).

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected static final class	ConcurrentArrayQueue.Block<E>

Field Summary

Fields

Modifier and Type	Field	Description
static final int	DEFAULT_BLOCK_SIZE
static final Object	REMOVED_ELEMENT

Constructor Summary

Constructors

Constructor	Description
ConcurrentArrayQueue()
ConcurrentArrayQueue(int blockSize)

Method Summary

Modifier and Type	Method	Description
protected boolean	casHeadBlock(ConcurrentArrayQueue.Block<T> current, ConcurrentArrayQueue.Block<T> update)
protected boolean	casTailBlock(ConcurrentArrayQueue.Block<T> current, ConcurrentArrayQueue.Block<T> update)
protected int	getBlockCount()
int	getBlockSize()
int	getExactSize()
protected ConcurrentArrayQueue.Block<T>	getHeadBlock()
protected ConcurrentArrayQueue.Block<T>	getTailBlock()
boolean	isEmpty()
Iterator<T>	iterator()
protected ConcurrentArrayQueue.Block<T>	newBlock()
boolean	offer(T item)
int	originalSize()	this method has been modified from original jetty version, it only returns a size rounded to 'blockSize'
T	peek()
T	poll()
boolean	remove(Object o)
boolean	removeAll(Collection<?> c)
boolean	retainAll(Collection<?> c)
int	size()

Methods inherited from class java.util.AbstractQueue

add, addAll, clear, element, remove

Methods inherited from class java.util.AbstractCollection

contains, containsAll, toArray, toArray, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Collection

contains, containsAll, equals, hashCode, parallelStream, removeIf, spliterator, stream, toArray, toArray, toArray

Methods inherited from interface java.lang.Iterable

forEach

Field Details

DEFAULT_BLOCK_SIZE

public static final int DEFAULT_BLOCK_SIZE

See Also:

• Constant Field Values

REMOVED_ELEMENT

public static final Object REMOVED_ELEMENT

Constructor Details

ConcurrentArrayQueue

public ConcurrentArrayQueue()

ConcurrentArrayQueue

public ConcurrentArrayQueue(int blockSize)

Method Details

getBlockSize

public int getBlockSize()

getHeadBlock

protected ConcurrentArrayQueue.Block<T> getHeadBlock()

getTailBlock

protected ConcurrentArrayQueue.Block<T> getTailBlock()

offer

public boolean offer(T item)

casTailBlock

protected boolean casTailBlock(ConcurrentArrayQueue.Block<T> current,
 ConcurrentArrayQueue.Block<T> update)

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in interface Collection<T>

Overrides:

isEmpty in class AbstractCollection<T>

poll

public T poll()

casHeadBlock

protected boolean casHeadBlock(ConcurrentArrayQueue.Block<T> current,
 ConcurrentArrayQueue.Block<T> update)

peek

public T peek()

remove

public boolean remove(Object o)

Specified by:

remove in interface Collection<T>

Overrides:

remove in class AbstractCollection<T>

removeAll

public boolean removeAll(Collection<?> c)

Specified by:

removeAll in interface Collection<T>

Overrides:

removeAll in class AbstractCollection<T>

retainAll

public boolean retainAll(Collection<?> c)

Specified by:

retainAll in interface Collection<T>

Overrides:

retainAll in class AbstractCollection<T>

iterator

public Iterator<T> iterator()

Specified by:

iterator in interface Collection<T>

Specified by:

iterator in interface Iterable<T>

Specified by:

iterator in class AbstractCollection<T>

size

public int size()

Specified by:

size in interface Collection<T>

Specified by:

size in class AbstractCollection<T>

originalSize

public int originalSize()

this method has been modified from original jetty version, it only returns a size rounded to 'blockSize'

Returns:

getExactSize

public int getExactSize()

newBlock

protected ConcurrentArrayQueue.Block<T> newBlock()

getBlockCount

protected int getBlockCount()