horstmann.ch08_queue

Class BoundedQueue<E>

java.lang.Object

java.util.AbstractCollection<E>

horstmann.ch08_queue.BoundedQueue<E>

All Implemented Interfaces:

java.lang.Iterable<E>, java.util.Collection<E>

public class BoundedQueue<E>
extends java.util.AbstractCollection<E>

A first-in, first-out bounded collection of objects.

Field Summary

Fields

Modifier and Type	Field and Description
private int	count
private java.util.ArrayList<E>	elements
private int	head
private int	tail

Constructor Summary

Constructors

Constructor and Description
BoundedQueue(int capacity) Constructs an empty queue.

Method Summary

Modifier and Type	Method and Description
boolean	add(E anObject) Append an object at tail.
boolean	isFull() Checks whether this queue is full.
java.util.Iterator<E>	iterator()
E	peek() Gets object at head.
E	remove() Remove object at head.
int	size()

Methods inherited from class java.util.AbstractCollection

addAll, clear, contains, containsAll, isEmpty, remove, removeAll, retainAll, toArray, toArray, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Collection

equals, hashCode, parallelStream, removeIf, spliterator, stream

Methods inherited from interface java.lang.Iterable

forEach

Field Detail

elements

private java.util.ArrayList<E> elements

head

private int head

tail

private int tail

count

private int count

Constructor Detail

BoundedQueue

public BoundedQueue(int capacity)

Constructs an empty queue.

Parameters:

capacity - the maximum capacity of the queue

Precondition: capacity > 0

Method Detail

iterator

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

Specified by:

iterator in interface java.lang.Iterable<E>

Specified by:

iterator in interface java.util.Collection<E>

Specified by:

iterator in class java.util.AbstractCollection<E>

remove

public E remove()

Remove object at head.

Returns:

the object that has been removed from the queue

Precondition: size() > 0

add

public boolean add(E anObject)

Append an object at tail.

Specified by:

add in interface java.util.Collection<E>

Overrides:

add in class java.util.AbstractCollection<E>

Parameters:

anObject - the object to be appended

Returns:

true since this operation modifies the queue. (This is a requirement of the collections framework.)

Precondition: !isFull()

size

public int size()

Specified by:

size in interface java.util.Collection<E>

Specified by:

size in class java.util.AbstractCollection<E>

isFull

public boolean isFull()

Checks whether this queue is full.

Returns:

true if the queue is full

peek

public E peek()

Gets object at head.

Returns:

the object that is at the head of the queue

Precondition: size() > 0