AbstractConcurrentArrayQueue (Agrona)

java.lang.Object
- org.agrona.concurrent.AbstractConcurrentArrayQueue<E>

All Implemented Interfaces:

Iterable<E>, Collection<E>, Queue<E>, Pipe<E>, QueuedPipe<E>

Direct Known Subclasses:

ManyToManyConcurrentArrayQueue, ManyToOneConcurrentArrayQueue, OneToOneConcurrentArrayQueue
```
public abstract class AbstractConcurrentArrayQueue<E>
extends Object
implements QueuedPipe<E>
```
Left over immutable queue fields.

Field Summary

Fields
Modifier and Type	Field and Description
`protected E[]`	`buffer` Backing array.
`protected static int`	`BUFFER_ARRAY_BASE` Array base.
`protected int`	`capacity` Queue capacity.
`protected long`	`head` Head index.
`protected static long`	`HEAD_OFFSET` Offset of the `head` field.
`protected long`	`headCache` Cached head index.
`protected static long`	`SHARED_HEAD_CACHE_OFFSET` Offset of the `sharedHeadCache` field.
`protected long`	`sharedHeadCache` Shared cached head index.
`protected static int`	`SHIFT_FOR_SCALE` Shift for scale.
`protected long`	`tail` Tail index.
`protected static long`	`TAIL_OFFSET` Offset of the `tail` field.

Constructor Summary

Constructors
Constructor and Description

AbstractConcurrentArrayQueue(int requestedCapacity)
Constructs a queue with the requested capacity.

Constructors
Constructor and Description
`AbstractConcurrentArrayQueue(int requestedCapacity)` Constructs a queue with the requested capacity.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`boolean`	`add(E e)`
`boolean`	`addAll(Collection<? extends E> c)`
`long`	`addedCount()` The number of items added to this container since creation.
`int`	`capacity()` The maximum capacity of this container to hold items.
`void`	`clear()`
`boolean`	`contains(Object o)`
`boolean`	`containsAll(Collection<?> c)`
`E`	`element()`
`boolean`	`isEmpty()`
`Iterator<E>`	`iterator()`
`E`	`peek()`
`int`	`remainingCapacity()` Get the remaining capacity for elements in the container given the current size.
`E`	`remove()`
`boolean`	`remove(Object o)`
`boolean`	`removeAll(Collection<?> c)`
`long`	`removedCount()` The number of items removed from this container since creation.
`boolean`	`retainAll(Collection<?> c)`
`static long`	`sequenceToBufferOffset(long sequence, long mask)` Compute buffer offset based on the given sequence and the mask.
`int`	`size()` The number of items currently in the container.
`Object[]`	`toArray()`
`<T> T[]`	`toArray(T[] a)`

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.util.Queue
offer, poll

Methods inherited from interface java.util.Collection
equals, hashCode, parallelStream, removeIf, spliterator, stream

Methods inherited from interface java.lang.Iterable
forEach

Methods inherited from interface org.agrona.concurrent.Pipe
drain, drain, drainTo

- Field Detail
  - TAIL_OFFSET
```
protected static final long TAIL_OFFSET
```
    Offset of the tail field.
  - SHARED_HEAD_CACHE_OFFSET
```
protected static final long SHARED_HEAD_CACHE_OFFSET
```
    Offset of the sharedHeadCache field.
  - HEAD_OFFSET
```
protected static final long HEAD_OFFSET
```
    Offset of the head field.
  - BUFFER_ARRAY_BASE
```
protected static final int BUFFER_ARRAY_BASE
```
    Array base.
  - SHIFT_FOR_SCALE
```
protected static final int SHIFT_FOR_SCALE
```
    Shift for scale.
  - capacity
```
protected final int capacity
```
    Queue capacity.
  - buffer
```
protected final E[] buffer
```
    Backing array.
  - head
```
protected volatile long head
```
    Head index.
  - tail
```
protected volatile long tail
```
    Tail index.
  - headCache
```
protected long headCache
```
    Cached head index.
  - sharedHeadCache
```
protected volatile long sharedHeadCache
```
    Shared cached head index.
- Constructor Detail
  - AbstractConcurrentArrayQueue
```
public AbstractConcurrentArrayQueue(int requestedCapacity)
```
    Constructs a queue with the requested capacity.
    
    Parameters:
    
    requestedCapacity - of the queue.
- Method Detail
  - addedCount
```
public long addedCount()
```
    The number of items added to this container since creation.
    
    Specified by:
    
    addedCount in interface Pipe<E>
    
    Returns:
    
    the number of items added.
  - removedCount
```
public long removedCount()
```
    The number of items removed from this container since creation.
    
    Specified by:
    
    removedCount in interface Pipe<E>
    
    Returns:
    
    the number of items removed.
  - capacity
```
public int capacity()
```
    The maximum capacity of this container to hold items.
    
    Specified by:
    
    capacity in interface Pipe<E>
    
    Returns:
    
    the capacity of the container.
  - remainingCapacity
```
public int remainingCapacity()
```
    Get the remaining capacity for elements in the container given the current size.
    
    Specified by:
    
    remainingCapacity in interface Pipe<E>
    
    Returns:
    
    remaining capacity of the container.
  - peek
```
public E peek()
```
    Specified by:
    
    peek in interface Queue<E>
  - add
```
public boolean add(E e)
```
    Specified by:
    
    add in interface Collection<E>
    
    Specified by:
    
    add in interface Queue<E>
  - remove
```
public E remove()
```
    Specified by:
    
    remove in interface Queue<E>
  - element
```
public E element()
```
    Specified by:
    
    element in interface Queue<E>
  - contains
```
public boolean contains(Object o)
```
    Specified by:
    
    contains in interface Collection<E>
  - iterator
```
public Iterator<E> iterator()
```
    Specified by:
    
    iterator in interface Iterable<E>
    
    Specified by:
    
    iterator in interface Collection<E>
  - toArray
```
public Object[] toArray()
```
    Specified by:
    
    toArray in interface Collection<E>
  - toArray
```
public <T> T[] toArray(T[] a)
```
    Specified by:
    
    toArray in interface Collection<E>
  - remove
```
public boolean remove(Object o)
```
    Specified by:
    
    remove in interface Collection<E>
  - containsAll
```
public boolean containsAll(Collection<?> c)
```
    Specified by:
    
    containsAll in interface Collection<E>
  - addAll
```
public boolean addAll(Collection<? extends E> c)
```
    Specified by:
    
    addAll in interface Collection<E>
  - removeAll
```
public boolean removeAll(Collection<?> c)
```
    Specified by:
    
    removeAll in interface Collection<E>
  - retainAll
```
public boolean retainAll(Collection<?> c)
```
    Specified by:
    
    retainAll in interface Collection<E>
  - clear
```
public void clear()
```
    Specified by:
    
    clear in interface Collection<E>
  - isEmpty
```
public boolean isEmpty()
```
    Specified by:
    
    isEmpty in interface Collection<E>
  - size
```
public int size()
```
    The number of items currently in the container.
    
    Specified by:
    
    size in interface Collection<E>
    
    Specified by:
    
    size in interface Pipe<E>
    
    Returns:
    
    number of items currently in the container.
  - sequenceToBufferOffset
```
public static long sequenceToBufferOffset(long sequence,
                                          long mask)
```
    Compute buffer offset based on the given sequence and the mask.
    
    Parameters:
    
    sequence - to compute the offset from.
    
    mask - to apply.
    
    Returns:
    
    buffer offset.

Class AbstractConcurrentArrayQueue<E>

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface java.util.Queue

Methods inherited from interface java.util.Collection

Methods inherited from interface java.lang.Iterable

Methods inherited from interface org.agrona.concurrent.Pipe

Field Detail

TAIL_OFFSET

SHARED_HEAD_CACHE_OFFSET

HEAD_OFFSET

BUFFER_ARRAY_BASE

SHIFT_FOR_SCALE

capacity

buffer

head

tail

headCache

sharedHeadCache

Constructor Detail

AbstractConcurrentArrayQueue

Method Detail

addedCount

removedCount

capacity

remainingCapacity

peek

add

remove

element

contains

iterator

toArray

toArray

remove

containsAll

addAll

removeAll

retainAll

clear

isEmpty

size

sequenceToBufferOffset