scranton.queue
Class QueueViaLinear1Circ

java.lang.Object
  scranton.queue.QueueViaLinear1Circ

All Implemented Interfaces:

Queue

public class QueueViaLinear1Circ

extends java.lang.Object

implements Queue

Implements the Queue interface via composition of the Linear1 class, which is used to represent the array as a circularly linked structure.

Field Summary

protected Linear1

actual Reference (possibly null) to the circularly recursively referenced structure that holds the queue's objects.

Constructor Summary

QueueViaLinear1Circ()
Constructs and empty queue

Method Summary

java.lang.Object	dequeue() Decrease the size of the queue by one by removing and returning reference to the object that was at the front of the queue.
void	enqueue(java.lang.Object item) Increase the size of the queue by one by placing item as the rear of the queue.
Queue	factory()
java.lang.Object	frontOf() Queue does not change, returns the reference to the front object in the queue.
boolean	isEmpty() Queue does not change, returns true iff the queue is empty.
java.lang.String	toString() Returns a string representation of the queue.

Methods inherited from class java.lang.Object

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

Field Detail

actual

protected Linear1 actual

Reference (possibly null) to the circularly recursively referenced structure that holds the queue's objects.

Constructor Detail

QueueViaLinear1Circ

public QueueViaLinear1Circ()

Constructs and empty queue

Method Detail

isEmpty

public boolean isEmpty()

Description copied from interface: Queue

Queue does not change, returns true iff the queue is empty.

Specifications:

Q'=Q
Return Q==()

Specified by:

isEmpty in interface Queue

Returns:

boolean Q==().

See Also:

Queue.isEmpty()

frontOf

public java.lang.Object frontOf()

Description copied from interface: Queue

Queue does not change, returns the reference to the front object in the queue.

Specifications:

Q!=()Q'=Q
Return a₀

Specified by:

frontOf in interface Queue

Returns:

Object Front of Queue.

See Also:

Queue.frontOf()

enqueue

public void enqueue(java.lang.Object item)

Description copied from interface: Queue

Increase the size of the queue by one by placing item as the rear of the queue.

Specifications:

Q'=(Q, obj)

Specified by:

enqueue in interface Queue

Parameters:

item - The new rear of the queue

See Also:

Queue.enqueue(java.lang.Object)

dequeue

public java.lang.Object dequeue()

Description copied from interface: Queue

Decrease the size of the queue by one by removing and returning reference to the object that was at the front of the queue. Note: The queue cannot be empty.

Specifications:

Q!=()Q = (a₀, Q')
Return: a₀

Specified by:

dequeue in interface Queue

Returns:

Object Front of queue.

See Also:

Queue.dequeue()

factory

public Queue factory()

toString

public java.lang.String toString()

Description copied from interface: Queue

Returns a string representation of the queue. The format of the representation is "FRONT[O_front\t...\tO_rear]REAR"

Specified by:

toString in interface Queue