it.unimi.dsi.fastutil.bytes
Class ByteArrayFIFOQueue

java.lang.Object
  extended by it.unimi.dsi.fastutil.AbstractPriorityQueue<Byte>
      extended by it.unimi.dsi.fastutil.bytes.AbstractBytePriorityQueue
          extended by it.unimi.dsi.fastutil.bytes.ByteArrayFIFOQueue
All Implemented Interfaces:
BytePriorityQueue, PriorityQueue<Byte>

public class ByteArrayFIFOQueue
extends AbstractBytePriorityQueue

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 as needed, but it is never shrunk. Use the trim() method to reduce its size, if necessary.

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


Field Summary
protected  byte[] array
          The backing array.
protected  int end
          The end position in array.
static int INITIAL_CAPACITY
          The standard initial capacity of a queue.
protected  int length
          The current (cached) length of array.
protected  int start
          The start position in array.
 
Constructor Summary
ByteArrayFIFOQueue()
          Creates a new empty queue with standard initial capacity.
ByteArrayFIFOQueue(int capacity)
          Creates a new empty queue with given capacity.
 
Method Summary
 void clear()
          Removes all elements from this queue.
 ByteComparator comparator()
          Returns null (FIFO queues have no comparator).
 byte dequeueByte()
          Dequeues the first element from the queue.
 byte dequeueLastByte()
          Dequeues the last element from the queue.
 void enqueue(byte x)
          Enqueues a new element.
 void enqueueFirst(byte x)
          Enqueues a new element as the first element (in dequeuing order) of the queue.
 byte firstByte()
          Returns the first element of the queue.
 byte lastByte()
          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.bytes.AbstractBytePriorityQueue
dequeue, enqueue, first, last
 
Methods inherited from class it.unimi.dsi.fastutil.AbstractPriorityQueue
changed, isEmpty
 
Methods inherited from class java.lang.Object
clone, equals, finalize, 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

array

protected byte[] array
The backing array.


length

protected int length
The current (cached) length of array.


start

protected int start
The start position in array. It is always strictly smaller than length.


end

protected int end
The end position in array. It is always strictly smaller than length. Might be actually smaller than start because array is used cyclically.

Constructor Detail

ByteArrayFIFOQueue

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

Parameters:
capacity - the initial capacity of this queue.

ByteArrayFIFOQueue

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

Method Detail

comparator

public ByteComparator comparator()
Returns null (FIFO queues have no comparator).

Returns:
null.
See Also:
PriorityQueue.comparator()

dequeueByte

public byte dequeueByte()
Description copied from interface: BytePriorityQueue
Dequeues the first element from the queue.

Returns:
the dequeued element.

dequeueLastByte

public byte dequeueLastByte()
Dequeues the last element from the queue.

Returns:
the dequeued element.
Throws:
NoSuchElementException - if the queue is empty.

enqueue

public void enqueue(byte x)
Description copied from interface: BytePriorityQueue
Enqueues a new element.

Parameters:
x - the element to enqueue.

enqueueFirst

public void enqueueFirst(byte x)
Enqueues a new element as the first element (in dequeuing order) of the queue.


firstByte

public byte firstByte()
Returns the first element of the queue.

Returns:
the first element of the queue.

lastByte

public byte lastByte()
Returns the last element of the queue.

Specified by:
lastByte in interface BytePriorityQueue
Overrides:
lastByte in class AbstractBytePriorityQueue
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.


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