Class AQueue<E>

java.lang.Object

AQueue<E>

All Implemented Interfaces:

IQueue<E>

Direct Known Subclasses:

ArrayQueue, LinkedQueue

public abstract class AQueue<E>
extends java.lang.Object
implements IQueue<E>

AQueue provides default implementations for several no-brainer methods in the IQueue interface.

Some methods in IQueue are pairs that do the same job, but report failure differently. Implement the fail-by-throwing methods here, in this abstract class, by calling the paired method and checking the return value, then throwing as appropriate. Why is defining these methods here desirable? What are some alternatives?

created by cspfrederick and garethhalladay Fall17
inspired by Chris Wilcox

Constructor Summary

Constructors

Constructor and Description
AQueue()

Method Summary

Modifier and Type	Method and Description
void	add(E item) Inserts the specified element into this queue, returning true upon success.
E	element() Retrieves, but does not remove, the head of this queue.
boolean	isEmpty() Returns true if this queue contains no elements.
E	remove() Retrieves and removes the head of this queue.

Methods inherited from class java.lang.Object

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

Methods inherited from interface IQueue

clear, contains, offer, peek, poll, size, toString

Constructor Detail

AQueue

public AQueue()

Method Detail

add

public void add(E item)

Description copied from interface: IQueue

Inserts the specified element into this queue, returning true upon success.

This method throws an IllegalStateException if no space is available to hold the new item.

Specified by:

add in interface IQueue<E>

Parameters:

item - the item to add

remove

public E remove()

Description copied from interface: IQueue

Retrieves and removes the head of this queue. This method differs from poll only in that it throws an exception if this queue is empty.

Specified by:

remove in interface IQueue<E>

Returns:

the head of this queue

element

public E element()

Description copied from interface: IQueue

Retrieves, but does not remove, the head of this queue. This method differs from peek only in that it throws an exception if this queue is empty.

Specified by:

element in interface IQueue<E>

Returns:

the head of this queue

isEmpty

public boolean isEmpty()

Description copied from interface: IQueue

Returns true if this queue contains no elements.

Specified by:

isEmpty in interface IQueue<E>

Returns:

true if this queue is empty, false otherwise