structure
Class QueueArray

java.lang.Object
  |
  +--structure.AbstractStructure
        |
        +--structure.AbstractLinear
              |
              +--structure.AbstractQueue
                    |
                    +--structure.QueueArray

All Implemented Interfaces:

Linear, Queue, Structure

public class QueueArray

extends AbstractQueue

implements Queue

An implementation of queues based on arrays. The head of the queue starts out at the head of the array, allowing the queue to grow and shrink in constant time. This queue implementation is ideal for applications that require a queue with a known maximum size that expands in constant time.

Example usage:

To compute the sum of the unicode value of every character in the standard input we could use the following:

 public static void main(String[] arguments)
 {
     int charsInInput = QueueExample.countChars(argument);
     QueueArray q = new QueueArray(charsInInput);
     int unicodeSum = 0;

     if(arguments.length > 0){
         for(int i=0; i < arguments.length; i++){
	       for(int j=0; j < arguments[i].length(); j++){
		   q.enqueue(new Character(arguments[i].charAt(j)));
	       }
	   }
     }

     while(!q.AbstractLinear.empty()){
	  char c = ((Character)q.AbstractQueue.dequeue()).charValue();
	  unicodeSum+=Character.getNumericValue(c);
     }

     System.out.println("Total Value: " + unicodeSum);
 }
 

See Also:

QueueList, QueueVector

Field Summary

protected int	count current size of queue
protected Object[]	data The references to values stored within the queue.
protected int	head index of the head of queue.

Constructor Summary

QueueArray(int size)
Construct a queue holding at most size elements.

Method Summary

void	add(Object value) Add a value to the tail of the queue.
void	clear() Remove all the values from the queue.
Object	get() Fetch the value at the head of the queue.
boolean	isEmpty() Determine if the queue is empty.
boolean	isFull() Determines if the queue is not able to accept any new values.
Iterator	iterator() Returns an iterator for traversing the structure.
Object	remove() Remove a value from the head of the queue.
int	size() Determine the number of elements within the queue
String	toString() Construct a string representation of the queue.

Methods inherited from class structure.AbstractQueue

dequeue, enqueue, getFirst, peek

Methods inherited from class structure.AbstractLinear

empty, remove

Methods inherited from class structure.AbstractStructure

contains, elements, hashCode, values

Methods inherited from class java.lang.Object

, clone, equals, finalize, getClass, notify, notifyAll, registerNatives, wait, wait, wait

Methods inherited from interface structure.Queue

dequeue, empty, enqueue, getFirst, peek

Methods inherited from interface structure.Structure

contains, elements, remove, values

Field Detail

data

protected Object[] data

The references to values stored within the queue.

head

protected int head

index of the head of queue.

count

protected int count

current size of queue

Constructor Detail

QueueArray

public QueueArray(int size)

Construct a queue holding at most size elements.

Parameters:

size - The maximum size of the queue.

Method Detail

add

public void add(Object value)

Add a value to the tail of the queue.

Specified by:

add in interface Queue

Parameters:

value - The value added.

Precondition:

the queue is not full

Postcondition:

the value is added to the tail of the structure

See Also:

AbstractQueue.enqueue(java.lang.Object)

remove

public Object remove()

Remove a value from the head of the queue.

Specified by:

remove in interface Queue

Precondition:

the queue is not empty

Postcondition:

the head of the queue is removed and returned

Returns:

The value actually removed.

See Also:

AbstractQueue.dequeue()

get

public Object get()

Fetch the value at the head of the queue.

Specified by:

get in interface Queue

Precondition:

the queue is not empty

Postcondition:

the element at the head of the queue is returned

Returns:

Reference to the first value of the queue.

size

public int size()

Determine the number of elements within the queue

Specified by:

size in interface Queue

Postcondition:

returns the number of elements in the queue

Returns:

The number of elements within the queue.

clear

public void clear()

Remove all the values from the queue.

Specified by:

clear in interface Structure

Postcondition:

removes all elements from the queue

isFull

public boolean isFull()

Determines if the queue is not able to accept any new values.

Postcondition:

returns true if the queue is at its capacity

Returns:

True iff the queue is full.

isEmpty

public boolean isEmpty()

Determine if the queue is empty.

Specified by:

isEmpty in interface Structure

Overrides:

isEmpty in class AbstractStructure

Postcondition:

returns true iff the queue is empty

Returns:

True iff the queue is empty.

iterator

public Iterator iterator()

Description copied from interface: Structure

Returns an iterator for traversing the structure.

Specified by:

iterator in interface Structure

Following copied from interface: structure.Structure

Returns:

an iterator for traversing the structure

See Also:

AbstractIterator, Iterator, Enumeration, Structure.elements()

toString

public String toString()

Construct a string representation of the queue.

Overrides:

toString in class Object

Postcondition:

returns string representation of queue

Returns:

String representing the queue.