org.agrona.collections

Class IntArrayQueue

java.lang.Object

java.util.AbstractCollection<E>

java.util.AbstractQueue<Integer>

org.agrona.collections.IntArrayQueue

All Implemented Interfaces:

Iterable<Integer>, Collection<Integer>, Queue<Integer>

public class IntArrayQueue
extends AbstractQueue<Integer>

Queue of ints which stores the elements without boxing. Null is represented by a special nullValue().

The IntArrayQueue.IntIterator is cached by default to avoid allocation unless directed to do so in the constructor.

Note: This class is not threadsafe.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	IntArrayQueue.IntIterator Specialised Iterator from which the value can be retrieved without boxing via IntArrayQueue.IntIterator.nextValue().

Field Summary

Fields

Modifier and Type	Field and Description
static int	DEFAULT_NULL_VALUE Default representation of null for an element.
static int	MIN_CAPACITY Minimum capacity for the queue which must also be a power of 2.

Constructor Summary

Constructors

Constructor and Description
IntArrayQueue() Construct a new queue defaulting to MIN_CAPACITY capacity, DEFAULT_NULL_VALUE and cached iterators.
IntArrayQueue(int nullValue) Construct a new queue defaulting to MIN_CAPACITY capacity and cached iterators.
IntArrayQueue(int initialCapacity, int nullValue) Construct a new queue default to cached iterators.
IntArrayQueue(int initialCapacity, int nullValue, boolean shouldAvoidAllocation) Construct a new queue providing all the config options.

Method Summary

Modifier and Type	Method and Description
boolean	add(Integer element)
boolean	addInt(int element) Offer an element to the tail of the queue without boxing.
int	capacity() The current capacity for the collection.
void	clear()
Integer	element()
int	elementInt() Peek at the element on the head of the queue without boxing.
void	forEach(Consumer<? super Integer> action)
void	forEachInt(IntConsumer action) Iterate over the collection without boxing.
boolean	isEmpty()
IntArrayQueue.IntIterator	iterator()
int	nullValue() The value representing a null element.
boolean	offer(Integer element)
boolean	offerInt(int element) Offer an element to the tail of the queue without boxing.
Integer	peek()
int	peekInt() Peek at the element on the head of the queue without boxing.
Integer	poll()
int	pollInt() Poll the element from the head of the queue without boxing.
Integer	remove()
int	removeInt() Remove the element at the head of the queue without boxing.
int	size()
String	toString()

Methods inherited from class java.util.AbstractQueue

addAll

Methods inherited from class java.util.AbstractCollection

contains, containsAll, remove, removeAll, retainAll, toArray, toArray

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, remove, removeAll, removeIf, retainAll, spliterator, stream, toArray, toArray

Field Detail

DEFAULT_NULL_VALUE

public static final int DEFAULT_NULL_VALUE

Default representation of null for an element.

See Also:

Constant Field Values

MIN_CAPACITY

public static final int MIN_CAPACITY

Minimum capacity for the queue which must also be a power of 2.

See Also:

Constant Field Values

Constructor Detail

IntArrayQueue

public IntArrayQueue()

Construct a new queue defaulting to MIN_CAPACITY capacity, DEFAULT_NULL_VALUE and cached iterators.

IntArrayQueue

public IntArrayQueue(int nullValue)

Construct a new queue defaulting to MIN_CAPACITY capacity and cached iterators.

Parameters:

nullValue - cannot be stored in the queue and used as a sentinel.

IntArrayQueue

public IntArrayQueue(int initialCapacity,
                     int nullValue)

Construct a new queue default to cached iterators.

Parameters:

initialCapacity - for the queue which will be rounded up to the nearest power of 2.

nullValue - which cannot be stored in the queue and used as a sentinel.

IntArrayQueue

public IntArrayQueue(int initialCapacity,
                     int nullValue,
                     boolean shouldAvoidAllocation)

Construct a new queue providing all the config options.

Parameters:

initialCapacity - for the queue which will be rounded up to the nearest power of 2.

nullValue - which cannot be stored in the queue and used as a sentinel.

shouldAvoidAllocation - true to cache the iterator otherwise false to allocate a new iterator each time.

Method Detail

nullValue

public int nullValue()

The value representing a null element.

Returns:

value representing a null element.

capacity

public int capacity()

The current capacity for the collection.

Returns:

the current capacity for the collection.

size

public int size()

Specified by:

size in interface Collection<Integer>

Specified by:

size in class AbstractCollection<Integer>

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in interface Collection<Integer>

Overrides:

isEmpty in class AbstractCollection<Integer>

clear

public void clear()

Specified by:

clear in interface Collection<Integer>

Overrides:

clear in class AbstractQueue<Integer>

offer

public boolean offer(Integer element)

offerInt

public boolean offerInt(int element)

Offer an element to the tail of the queue without boxing.

Parameters:

element - to be offered to the queue.

Returns:

will always be true as long as the underlying array can be expanded.

add

public boolean add(Integer element)

Specified by:

add in interface Collection<Integer>

Specified by:

add in interface Queue<Integer>

Overrides:

add in class AbstractQueue<Integer>

addInt

public boolean addInt(int element)

Offer an element to the tail of the queue without boxing.

Parameters:

element - to be offered to the queue.

Returns:

will always be true as long as the underlying array can be expanded.

peek

public Integer peek()

peekInt

public int peekInt()

Peek at the element on the head of the queue without boxing.

Returns:

the element at the head of the queue without removing it.

poll

public Integer poll()

pollInt

public int pollInt()

Poll the element from the head of the queue without boxing.

Returns:

the element at the head of the queue removing it. If empty then nullValue.

remove

public Integer remove()

Specified by:

remove in interface Queue<Integer>

Overrides:

remove in class AbstractQueue<Integer>

element

public Integer element()

Specified by:

element in interface Queue<Integer>

Overrides:

element in class AbstractQueue<Integer>

elementInt

public int elementInt()

Peek at the element on the head of the queue without boxing.

Returns:

the element at the head of the queue without removing it.

Throws:

NoSuchElementException - if the queue is empty.

removeInt

public int removeInt()

Remove the element at the head of the queue without boxing.

Returns:

the element at the head of the queue.

Throws:

NoSuchElementException - if the queue is empty.

toString

public String toString()

Overrides:

toString in class AbstractCollection<Integer>

forEach

public void forEach(Consumer<? super Integer> action)

forEachInt

public void forEachInt(IntConsumer action)

Iterate over the collection without boxing.

Parameters:

action - to be taken for each element.

iterator

public IntArrayQueue.IntIterator iterator()

Specified by:

iterator in interface Iterable<Integer>

Specified by:

iterator in interface Collection<Integer>

Specified by:

iterator in class AbstractCollection<Integer>