org.exolab.jms.messagemgr
Class MessageQueue

java.lang.Object
  |
  +--org.exolab.jms.messagemgr.MessageQueue

public class MessageQueue

extends java.lang.Object

The message queue stored messages based on a comparator. The implementation is based on a synchronized linked list.

We can easily improve on this implementation and this implementation is not synchronized.

Version:

$Revision: 1.32.2.1 $ $Date: 2004/05/01 12:01:15 $

Author:

Jim Alateras, Tim Anderson

Constructor Summary

MessageQueue(java.util.Comparator comparator)
Instantiate an instance of this class with the specified comparator the comparator is used to order the elements in the queue.

Method Summary

void	add(java.lang.Object object) Add this element to the queue in the required order.
void	clear() Remove all the elements from the queue
boolean	contains(java.lang.Object object) Check if the specified object exists
java.lang.Object	first() Returns the first element in the queue.
boolean	isEmpty() Check if the queue is empty
java.util.Iterator	iterator() Return an iterator to the list
java.lang.Object	last() Returns the last element in the queue.
boolean	remove(java.lang.Object object) Remove the object from the queue
java.lang.Object	removeFirst() Removes and returns the first element on the queue.
java.lang.Object	removeLast() Removes and returns the last element in the queue
int	size() Return the number elements in the queue
java.lang.Object[]	toArray() Return all elements in the collection

Methods inherited from class java.lang.Object

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

Constructor Detail

MessageQueue

public MessageQueue(java.util.Comparator comparator)

Instantiate an instance of this class with the specified comparator the comparator is used to order the elements in the queue. Elements with the same order value are placed after each other.

Parameters:

comparator - used for ordering

Method Detail

add

public void add(java.lang.Object object)

Add this element to the queue in the required order. It uses a binary search to locate the correct position

Parameters:

object - object to add

contains

public boolean contains(java.lang.Object object)

Check if the specified object exists

Parameters:

object - - object to check

Returns:

boolean - true if it is contained

isEmpty

public boolean isEmpty()

Check if the queue is empty

Returns:

boolean - true if the queue is empty

toArray

public java.lang.Object[] toArray()

Return all elements in the collection

Returns:

Object[] array of elements to return

iterator

public java.util.Iterator iterator()

Return an iterator to the list

Returns:

Iterator

remove

public boolean remove(java.lang.Object object)

Remove the object from the queue

Parameters:

object - object to remove

clear

public void clear()

Remove all the elements from the queue

size

public int size()

Return the number elements in the queue

Returns:

int size of the queue

first

public java.lang.Object first()

Returns the first element in the queue.

Returns:

the first element in the queue, or null, if the queue is empty

last

public java.lang.Object last()

Returns the last element in the queue.

Returns:

the last element in the queue, or null, if the queue is empty

removeFirst

public java.lang.Object removeFirst()

Removes and returns the first element on the queue.

Returns:

the first element in the queue, or null, if the queue is empty

removeLast

public java.lang.Object removeLast()

Removes and returns the last element in the queue

Returns:

the last element in the queue, or null, if the queue is empty