anon.util

Class ObjectQueue

java.lang.Object

anon.util.ObjectQueue

public class ObjectQueue
extends java.lang.Object

This is a generic FIFO object queue.

Author:

Rolf Wendolsky

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private class	ObjectQueue.QueueItem Simple LinkedList-like list item used in the ObjectQueue class.

Field Summary

Fields

Modifier and Type	Field and Description
private boolean	m_bClosed Signals if the take() method should stop blocking.
private ObjectQueue.QueueItem	m_foot Least recently added object.
private ObjectQueue.QueueItem	m_head Most recently added object.
private int	m_size Number of objects currently in the queue.

Constructor Summary

Constructors

Constructor and Description
ObjectQueue()

Method Summary

Modifier and Type	Method and Description
void	close() Signals the closing of this queue, interrupting any running take() method calls.
int	getSize() Returns the number of objects currently in the queue.
boolean	isEmpty()
java.lang.Object	poll(int a_msTimeout) Tries returning an object using pop().
java.lang.Object	pop() Returns the least recent object in the queue.
void	push(java.lang.Object a_object) Pushes an object to the head of the queue.
java.lang.Object	take() If the queue is empty this method blocks until a new item is available or the queue has been closed using close().

Methods inherited from class java.lang.Object

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

Field Detail

m_head

private ObjectQueue.QueueItem m_head

Most recently added object. Last to go out.

m_foot

private ObjectQueue.QueueItem m_foot

Least recently added object. First to go out.

m_size

private int m_size

Number of objects currently in the queue. If the same object has been pushed multiple times it will be counted multiple times.

m_bClosed

private volatile boolean m_bClosed

Signals if the take() method should stop blocking.

Constructor Detail

ObjectQueue

public ObjectQueue()

Method Detail

getSize

public int getSize()

Returns the number of objects currently in the queue. If the same object has been pushed multiple times it will be counted multiple times.

Returns:

Size of the queue.

close

public void close()

Signals the closing of this queue, interrupting any running take() method calls.

Note: This doesn't affect any other method calls and gets undone, when pushing an object into the queue.

push

public void push(java.lang.Object a_object)

Pushes an object to the head of the queue.

Parameters:

a_object -

pop

public java.lang.Object pop()

Returns the least recent object in the queue. If the queue is empty returns null.

Returns:

The tail of the queue, null if queue is empty.

take

public java.lang.Object take()

If the queue is empty this method blocks until a new item is available or the queue has been closed using close().

Returns:

The tail of the queue, null if the queue is closed.

poll

public java.lang.Object poll(int a_msTimeout)
                      throws java.lang.InterruptedException

Tries returning an object using pop(). If no object was available it waits a_msTimeout milliseconds and calls pop(), returning the result.

Parameters:

a_msTimeout - Amount of milliseconds to wait, if queue is empty.

Returns:

Object received from pop(). null, if null was returned.

Throws:

java.lang.InterruptedException

isEmpty

public boolean isEmpty()