jvx.util

Class PuQueue

java.lang.Object

jvx.util.PuQueue

public class PuQueue
extends java.lang.Object

This class provides the functionality of a queue or a stack of integers. Elements can be inserted into the queue, and its youngest and oldest elements can be extracted (Thus, this queue is acting as a "first in first out" queue, or a "last in first out" stack). Internally, the elements are organized within an array, which is automatically expanded if the size is too small. Running time of all operations is O(1); the only exception is the enqueue operation, which has only amortized running time of O(log(n)), due to resizing.

Author:

Felix Kaelberer

Version:

06.09.09, 1.20 revised (fk) Implemented copyNew().
13.12.06, 1.10 revised (mn) Implemented setSize() and changed the amount of dynamic resizing.
16.01.06, 1.00 created (fk)

Constructor Summary

Constructors

Constructor and Description
PuQueue() Construct an empty queue.
PuQueue(int size) Construct a queue with array of size size.
PuQueue(int[] entries) Construct a queue the entries of a given array.

Method Summary

Modifier and Type	Method and Description
void	copy(PuQueue queue) Copy all properties of the argument to this.
static PuQueue	copyNew(PuQueue queue) Create and return copy of this.
void	enqueue(int value) Insert an element into the queue.
int	extractFirst() Get the oldest element of the queue, i.e.the element which was inserted first.
int	extractLast() Get the youngest element of the queue, i.e.the element which was inserted last.
int	getNumEntries() Get number of elements in the queue.
int	getSize() Get maximum number of entries of the queue.
boolean	isEmpty() Whether the queue has no entries.
void	removeAll() Remove all elements from queue.
void	setSize(int size) Set the size of the queue.
PiVector	toPiVector() Create a PiVector with the entries of the queue.
java.lang.String	toString() Get a string containing all elements of the queue.

Methods inherited from class java.lang.Object

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

Constructor Detail

PuQueue

public PuQueue()

Construct an empty queue.

PuQueue

public PuQueue(int size)

Construct a queue with array of size size. Initial number of entries is 0.

Parameters:

size - Size of the queue.

Author:

Felix Kaelberer

Version:

16.01.06, 1.00 created (fk)

PuQueue

public PuQueue(int[] entries)

Construct a queue the entries of a given array.

Parameters:

entries - Initial entries of the queue.

Author:

Felix Kaelberer

Version:

01.02.2007, 1.00 created (fk)

Method Detail

copy

public void copy(PuQueue queue)

Copy all properties of the argument to this.

Parameters:

queue - The queue to copy.

Author:

Felix Kaelberer

Version:

16.01.06, 1.00 created (fk)

copyNew

public static PuQueue copyNew(PuQueue queue)

Create and return copy of this.

Parameters:

queue - The queue to copy.

Author:

Felix Kaelberer

Version:

30.06.09, 1.00 created (fk)

getNumEntries

public int getNumEntries()

Get number of elements in the queue.

Author:

Felix Kaelberer

Version:

16.01.06, 1.00 created (fk)

getSize

public int getSize()

Get maximum number of entries of the queue.

Version:

06.12.06, 1.00 created (mn)

enqueue

public void enqueue(int value)

Insert an element into the queue. The queue is automatically enlarged, if required.

Parameters:

value - Item to enqueue.

Author:

Felix Kaelberer

Version:

16.01.06, 1.00 created (fk)

setSize

public void setSize(int size)

Set the size of the queue. Existing elements will be copied to the new data structures. If the size is smaller then the number of elements, then then last elements will be removed.

Parameters:

size - New size of the queue.

Author:

Matthias Nieser

Version:

13.12.06, 1.00 created (mn)

extractFirst

public int extractFirst()

Get the oldest element of the queue, i.e.the element which was inserted first.

Author:

Felix Kaelberer

Version:

16.01.06, 1.00 created (fk)

extractLast

public int extractLast()

Get the youngest element of the queue, i.e.the element which was inserted last.

Author:

Felix Kaelberer

Version:

16.01.06, 1.00 created (fk)

toString

public java.lang.String toString()

Get a string containing all elements of the queue.

Overrides:

toString in class java.lang.Object

Author:

Felix Kaelberer

Version:

07.02.07, 1.00 revised (fk) Separate entries with comma, use brackets.
16.01.06, 1.00 created (fk)

toPiVector

public PiVector toPiVector()

Create a PiVector with the entries of the queue.

Returns:

PiVector of size getNumEntries() containing the entries of the queue.;

Author:

Felix Kaelberer

Version:

01.02.2007, 1.00 created (fk)

removeAll

public void removeAll()

Remove all elements from queue.

Version:

06.12.06, 1.00 created (mn)

isEmpty

public boolean isEmpty()

Whether the queue has no entries.

Version:

06.12.06, 1.00 created (mn)