it.unimi.dsi.fastutil.doubles
Class DoubleArrayFIFOQueue

java.lang.Object
  it.unimi.dsi.fastutil.AbstractPriorityQueue<java.lang.Double>
      it.unimi.dsi.fastutil.doubles.AbstractDoublePriorityQueue
          it.unimi.dsi.fastutil.doubles.DoubleArrayFIFOQueue

All Implemented Interfaces:

DoublePriorityQueue, PriorityQueue<java.lang.Double>

public class DoubleArrayFIFOQueue
extends AbstractDoublePriorityQueue

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).

Field Summary

static int

INITIAL_CAPACITY The standard initial capacity of a queue.

Constructor Summary

DoubleArrayFIFOQueue()
Creates a new empty queue with standard initial capacity.

DoubleArrayFIFOQueue(int capacity)
Creates a new empty queue with given capacity.

Method Summary

void	clear() Removes all elements from this queue.
DoubleComparator	comparator() Returns null (FIFO queues have no comparator).
double	dequeueDouble() Dequeues the first element from the queue.
double	dequeueLastDouble() Dequeues the last element from the queue.
void	enqueue(double x) Enqueues a new element.
void	enqueueFirst(double x) Enqueues a new element as the first element (in dequeuing order) of the queue.
double	firstDouble() Returns the first element of the queue.
double	lastDouble() Returns the last element of the queue.
int	size() Returns the number of elements in this queue.
void	trim() Trims the queue to the smallest possible size.

Methods inherited from class it.unimi.dsi.fastutil.doubles.AbstractDoublePriorityQueue

dequeue, enqueue, first, last

Methods inherited from class it.unimi.dsi.fastutil.AbstractPriorityQueue

changed, isEmpty

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

DoubleArrayFIFOQueue

public DoubleArrayFIFOQueue(int capacity)

Creates a new empty queue with given capacity.

Parameters:

capacity - the initial capacity of this queue.

DoubleArrayFIFOQueue

public DoubleArrayFIFOQueue()

Creates a new empty queue with standard initial capacity.

Method Detail

comparator

public DoubleComparator comparator()

Returns null (FIFO queues have no comparator).

Returns:

null.

See Also:

PriorityQueue.comparator()

dequeueDouble

public double dequeueDouble()

Description copied from interface: DoublePriorityQueue

Dequeues the first element from the queue.

Returns:

the dequeued element.

dequeueLastDouble

public double dequeueLastDouble()

Dequeues the last element from the queue.

Returns:

the dequeued element.

Throws:

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

enqueue

public void enqueue(double x)

Description copied from interface: DoublePriorityQueue

Enqueues a new element.

Parameters:

x - the element to enqueue.

enqueueFirst

public void enqueueFirst(double x)

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

firstDouble

public double firstDouble()

Returns the first element of the queue.

Returns:

the first element of the queue.

lastDouble

public double lastDouble()

Returns the last element of the queue.

Specified by:

lastDouble in interface DoublePriorityQueue

Overrides:

lastDouble in class AbstractDoublePriorityQueue

Returns:

the last element of the queue.

clear

public void clear()

Description copied from interface: PriorityQueue

Removes all elements from this queue.

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.

Returns:

the number of elements in this queue.