Class MessagePriorityQueue

java.lang.Object

MessagePriorityQueue

public class MessagePriorityQueue
extends java.lang.Object

This class creates a priority queue using MessageQueues for each priority level. The constructor initializes each MessageQueue. Otherwise, the queue has the needed methods: add(), remove(), peek(), and isEmpty(). All of these methods are O(1). Currently, this class has five priority levels, as set by the integer constant NUM_PRIORITIES.

Author:

AnneMarie Caballero (annemariecabs)

Field Summary

Fields

Modifier and Type	Field	Description
static int	NUM_PRIORITIES	The number of priorities available for this MessagePriorityQueue
private java.util.ArrayList<MessageQueue>	queues	An ArrayList of MessageQueues which will hold the values for the priority queue; each MessageQueue represents a priority level

Constructor Summary

Constructors

Constructor	Description
MessagePriorityQueue()	Constructs a MessagePriorityQueue object by initializing each queue in the queues field

Method Summary

Modifier and Type	Method	Description
void	add(Message msg)	Adds a Message to the MessageQueue at the index of its priority in queues
boolean	isEmpty()	Returns whether the queue is empty
Message	peek()	Returns the highest-priority Message (0 is the highest, 4 is the lowest)
Message	remove()	Returns and removes the highest-priority Message (0 is the highest, 4 is the lowest)

Methods inherited from class java.lang.Object

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

Field Detail

queues

private java.util.ArrayList<MessageQueue> queues

An ArrayList of MessageQueues which will hold the values for the priority queue; each MessageQueue represents a priority level

NUM_PRIORITIES

public static final int NUM_PRIORITIES

The number of priorities available for this MessagePriorityQueue

See Also:

Constant Field Values

Constructor Detail

MessagePriorityQueue

public MessagePriorityQueue()

Constructs a MessagePriorityQueue object by initializing each queue in the queues field

Method Detail

add

public void add(Message msg)

Adds a Message to the MessageQueue at the index of its priority in queues

Parameters:

msg - the Message to be added

remove

public Message remove()

Returns and removes the highest-priority Message (0 is the highest, 4 is the lowest)

Returns:

the highest priority Message, null otherwise

peek

public Message peek()

Returns the highest-priority Message (0 is the highest, 4 is the lowest)

Returns:

the highest priority Message, null otherwise

isEmpty

public boolean isEmpty()

Returns whether the queue is empty

Returns:

true if the queue is empty, null if there are any Messages in the queue