stockportfolio
Class ObjectDQueue

java.lang.Object
  stockportfolio.ObjectDQueue

All Implemented Interfaces:

IDQueue, IQueue

Direct Known Subclasses:

StockQueue

public class ObjectDQueue

extends java.lang.Object

implements IDQueue

An enhanced queue. Can addToFront, and get the elements by idenx.

Constructor Summary

ObjectDQueue()

Method Summary

boolean	addToFront(java.lang.Object newValue) Add (push) an element to the front of the queue; thus, the next dequeue operation would return this value, assuming there were no other intervening addToFront operations.
java.lang.Object	dequeue() Remove an object from the queue.
boolean	enqueue(java.lang.Object newValue) Push a new object on the queue.
java.lang.Object	front() Look at the front of the queue.
java.lang.Object	getObject(int index) Get an object from the queue.
boolean	isEmpty() Tell whether the queue is empty.
boolean	isFull() Tell whether the queue is full.
int	size() Tells how many objects are currently in the queue.

Methods inherited from class java.lang.Object

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

Constructor Detail

ObjectDQueue

public ObjectDQueue()

Method Detail

addToFront

public boolean addToFront(java.lang.Object newValue)

Description copied from interface: IDQueue

Add (push) an element to the front of the queue; thus, the next dequeue operation would return this value, assuming there were no other intervening addToFront operations.

Specified by:

addToFront in interface IDQueue

Parameters:

newValue - a non-null object

Returns:

true iff the object was successfully added to the queue.

getObject

public java.lang.Object getObject(int index)

Description copied from interface: IDQueue

Get an object from the queue. The object is not dequeued and the stack is unchanged.

Specified by:

getObject in interface IDQueue

Parameters:

index - an index number, with 0 being the oldest object (i.e., the one at the front of the queue), 1 being next oldest, etc.

Returns:

the object corresponding to blocknum

dequeue

public java.lang.Object dequeue()

Description copied from interface: IQueue

Remove an object from the queue.

Specified by:

dequeue in interface IQueue

Returns:

a reference to the front of the queue, or null if the queue is empty. The size of the queue has decreased by 1. Note that the reference is to the actual enqueued object, not to a clone.

enqueue

public boolean enqueue(java.lang.Object newValue)

Description copied from interface: IQueue

Push a new object on the queue.

Specified by:

enqueue in interface IQueue

Parameters:

newValue - a non-null object

Returns:

true iff the operation succeeded. In this case, the newValue is now the top of the queue and the previous top is just below it; the size of the queue has increased by 1.

front

public java.lang.Object front()

Description copied from interface: IQueue

Look at the front of the queue. The queue itself is unchanged.

Specified by:

front in interface IQueue

Returns:

the front of the queue, or null if the queue is empty. Note that the reference is to the actual enqueued object, not to a clone.

isEmpty

public boolean isEmpty()

Description copied from interface: IQueue

Tell whether the queue is empty.

Specified by:

isEmpty in interface IQueue

Returns:

true iff the queue is empty (has size 0).

isFull

public boolean isFull()

Description copied from interface: IQueue

Tell whether the queue is full.

Specified by:

isFull in interface IQueue

Returns:

true iff the queue is full, i.e., whether it is possible to another another object to it.

size

public int size()

Description copied from interface: IQueue

Tells how many objects are currently in the queue.

Specified by:

size in interface IQueue

Returns:

the number of objects in the queue, always >= 0