structure5
Class QueueArray<E>

java.lang.Object
  structure5.AbstractStructure<E>
      structure5.AbstractLinear<E>
          structure5.AbstractQueue<E>
              structure5.QueueArray<E>

All Implemented Interfaces:

java.lang.Iterable<E>, Linear<E>, Queue<E>, Structure<E>

public class QueueArray<E>
extends AbstractQueue<E>
implements Queue<E>

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 java.lang.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(E value) Add a value to the tail of the queue.
void	clear() Remove all the values from the queue.
E	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.
java.util.Iterator<E>	iterator() Returns an iterator for traversing the structure.
E	remove() Remove a value from the head of the queue.
int	size() Determine the number of elements within the queue
java.lang.String	toString() Construct a string representation of the queue.

Methods inherited from class structure5.AbstractQueue

dequeue, enqueue, getFirst, peek

Methods inherited from class structure5.AbstractLinear

empty, remove

Methods inherited from class structure5.AbstractStructure

contains, elements, hashCode, values

Methods inherited from class java.lang.Object

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

Methods inherited from interface structure5.Queue

dequeue, empty, enqueue, getFirst, peek

Methods inherited from interface structure5.Structure

contains, elements, remove, values

Field Detail

data

protected java.lang.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.

Postcondition:

create a queue capable of holding at most size values

Method Detail

add

public void add(E value)

Add a value to the tail of the queue.

Specified by:

add in interface Linear<E>

Specified by:

add in interface Queue<E>

Specified by:

add in interface Structure<E>

Parameters:

value - The value added.

See Also:

AbstractQueue.enqueue(E)

Precondition:

the queue is not full

Postcondition:

the value is added to the tail of the structure

remove

public E remove()

Remove a value from the head of the queue.

Specified by:

remove in interface Linear<E>

Specified by:

remove in interface Queue<E>

Returns:

The value actually removed.

See Also:

AbstractQueue.dequeue()

Precondition:

the queue is not empty

Postcondition:

the head of the queue is removed and returned

get

public E get()

Fetch the value at the head of the queue.

Specified by:

get in interface Linear<E>

Specified by:

get in interface Queue<E>

Returns:

Reference to the first value of the queue.

Precondition:

the queue is not empty

Postcondition:

the element at the head of the queue is returned

size

public int size()

Determine the number of elements within the queue

Specified by:

size in interface Linear<E>

Specified by:

size in interface Queue<E>

Specified by:

size in interface Structure<E>

Returns:

The number of elements within the queue.

Postcondition:

returns the number of elements in the queue

clear

public void clear()

Remove all the values from the queue.

Specified by:

clear in interface Structure<E>

Postcondition:

removes all elements from the queue

isFull

public boolean isFull()

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

Returns:

True iff the queue is full.

Postcondition:

returns true if the queue is at its capacity

isEmpty

public boolean isEmpty()

Determine if the queue is empty.

Specified by:

isEmpty in interface Structure<E>

Overrides:

isEmpty in class AbstractStructure<E>

Returns:

True iff the queue is empty.

Postcondition:

returns true iff the queue is empty

iterator

public java.util.Iterator<E> iterator()

Description copied from interface: Structure

Returns an iterator for traversing the structure.

Specified by:

iterator in interface java.lang.Iterable<E>

Specified by:

iterator in interface Structure<E>

Returns:

an iterator for traversing the structure

See Also:

AbstractIterator, Iterator, Enumeration, Structure.elements()

toString

public java.lang.String toString()

Construct a string representation of the queue.

Overrides:

toString in class java.lang.Object

Returns:

String representing the queue.

Postcondition:

returns string representation of queue