Package it.unimi.dsi.fastutil.ints

Class IntArrayFIFOQueue

java.lang.Object

it.unimi.dsi.fastutil.ints.IntArrayFIFOQueue

All Implemented Interfaces:

IntPriorityQueue, PriorityQueue<java.lang.Integer>, java.io.Serializable

public class IntArrayFIFOQueue
extends java.lang.Object
implements IntPriorityQueue, java.io.Serializable

A type-specific array-based FIFO queue, supporting also deque operations.

Instances of this class represent a FIFO queue using a backing array in a circular way. The array is enlarged and shrunk as needed. You can use the trim() method to reduce its memory usage, if necessary.

This class provides additional methods that implement a deque (double-ended queue).

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
static int	INITIAL_CAPACITY	The standard initial capacity of a queue.

Constructor Summary

Constructors

Constructor	Description
IntArrayFIFOQueue()	Creates a new empty queue with standard initial capacity.
IntArrayFIFOQueue(int capacity)	Creates a new empty queue with given capacity.

Method Summary

Modifier and Type	Method	Description
void	clear()	Removes all elements from this queue.
IntComparator	comparator()	Returns the comparator associated with this priority queue, or null if it uses its elements' natural ordering.
int	dequeueInt()	Dequeues the first element from the queue.
int	dequeueLastInt()	Dequeues the last element from the queue.
void	enqueue(int x)	Enqueues a new element.
void	enqueueFirst(int x)	Enqueues a new element as the first element (in dequeuing order) of the queue.
int	firstInt()	Returns the first element of the queue.
int	lastInt()	Returns the last element of the queue, that is, the element the would be dequeued last (optional operation).
int	size()	Returns the number of elements in this queue.
void	trim()	Trims the queue to the smallest possible size.

Methods inherited from interface it.unimi.dsi.fastutil.ints.IntPriorityQueue

dequeue, enqueue, first, last

Methods inherited from class java.lang.Object

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

Methods inherited from interface it.unimi.dsi.fastutil.PriorityQueue

changed, isEmpty

Field Detail

INITIAL_CAPACITY

public static final int INITIAL_CAPACITY

The standard initial capacity of a queue.

See Also:

Constant Field Values

Constructor Detail

IntArrayFIFOQueue

public IntArrayFIFOQueue(int capacity)

Creates a new empty queue with given capacity.

Parameters:

capacity - the initial capacity of this queue.

IntArrayFIFOQueue

public IntArrayFIFOQueue()

Creates a new empty queue with standard initial capacity.

Method Detail

comparator

public IntComparator comparator()

Returns the comparator associated with this priority queue, or null if it uses its elements' natural ordering.

Note that this specification strengthens the one given in PriorityQueue.comparator().

This implementation returns null (FIFO queues have no comparator).

Specified by:

comparator in interface IntPriorityQueue

Specified by:

comparator in interface PriorityQueue<java.lang.Integer>

Returns:

the comparator associated with this priority queue.

See Also:

PriorityQueue.comparator()

dequeueInt

public int dequeueInt()

Description copied from interface: IntPriorityQueue

Dequeues the first element from the queue.

Specified by:

dequeueInt in interface IntPriorityQueue

Returns:

the dequeued element.

See Also:

IntPriorityQueue.dequeue()

dequeueLastInt

public int dequeueLastInt()

Dequeues the last element from the queue.

Returns:

the dequeued element.

Throws:

java.util.NoSuchElementException - if the queue is empty.

enqueue

public void enqueue(int x)

Description copied from interface: IntPriorityQueue

Enqueues a new element.

Specified by:

enqueue in interface IntPriorityQueue

Parameters:

x - the element to enqueue.

See Also:

PriorityQueue.enqueue(Object)

enqueueFirst

public void enqueueFirst(int x)

Enqueues a new element as the first element (in dequeuing order) of the queue.

Parameters:

x - the element to enqueue.

firstInt

public int firstInt()

Description copied from interface: IntPriorityQueue

Returns the first element of the queue.

Specified by:

firstInt in interface IntPriorityQueue

Returns:

the first element.

See Also:

IntPriorityQueue.first()

lastInt

public int lastInt()

Description copied from interface: IntPriorityQueue

Returns the last element of the queue, that is, the element the would be dequeued last (optional operation).

This default implementation just throws an UnsupportedOperationException.

Specified by:

lastInt in interface IntPriorityQueue

Returns:

the last element.

See Also:

IntPriorityQueue.last()

clear

public void clear()

Description copied from interface: PriorityQueue

Removes all elements from this queue.

Specified by:

clear in interface PriorityQueue<java.lang.Integer>

trim

public void trim()

Trims the queue to the smallest possible size.

size

public int size()

Description copied from interface: PriorityQueue

Returns the number of elements in this queue.

Specified by:

size in interface PriorityQueue<java.lang.Integer>

Returns:

the number of elements in this queue.