horstmann.ch02_mail

Class MessageQueue

java.lang.Object

horstmann.ch02_mail.MessageQueue

public class MessageQueue
extends java.lang.Object

A first-in, first-out collection of messages. This implementation is not very efficient. We will consider a more efficient implementation in chapter 3.

Field Summary

Fields

Modifier and Type	Field and Description
private java.util.ArrayList<Message>	queue

Constructor Summary

Constructors

Constructor and Description
MessageQueue() Constructs an empty message queue.

Method Summary

Modifier and Type	Method and Description
void	add(Message newMessage) Append message at tail.
Message	peek() Get message at head.
Message	remove() Remove message at head.
int	size() Get the total number of messages in the queue.

Methods inherited from class java.lang.Object

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

Field Detail

queue

private java.util.ArrayList<Message> queue

Constructor Detail

MessageQueue

public MessageQueue()

Constructs an empty message queue.

Method Detail

remove

public Message remove()

Remove message at head.

Returns:

message that has been removed from the queue

add

public void add(Message newMessage)

Append message at tail.

Parameters:

newMessage - the message to be appended

size

public int size()

Get the total number of messages in the queue.

Returns:

the total number of messages in the queue

peek

public Message peek()

Get message at head.

Returns:

message that is at the head of the queue, or null if the queue is empty