org.jboss.messaging.core
Class ChannelSupport

java.lang.Object
  org.jboss.messaging.core.ChannelSupport

All Implemented Interfaces:

Channel, DeliveryObserver, Distributor, Receiver

Direct Known Subclasses:

PagingChannelSupport

public abstract class ChannelSupport

extends java.lang.Object

implements Channel

This class provides much of the functionality needed to implement a channel. This partial implementation supports atomicity, isolation and recoverability of reliable messages.

Version:

$Revision: 2724 $ $Id: ChannelSupport.java,v 1.65 2006/06/27 19:44:39 timfox Exp $

Author:

Ovidiu Feodorov, Tim Fox

Field Summary

protected boolean	acceptReliableMessages
protected boolean	active
protected long	channelID
protected SynchronizedInt	deliveringCount
protected int	maxSize
protected PriorityLinkedList	messageRefs
protected SynchronizedInt	messagesAdded
protected MessageStore	ms
protected PersistenceManager	pm
protected boolean	receiversReady
protected boolean	recoverable
protected java.lang.Object	refLock
protected Router	router
protected java.util.Set	scheduledDeliveries

Constructor Summary

protected

ChannelSupport(long channelID, MessageStore ms, PersistenceManager pm, boolean acceptReliableMessages, boolean recoverable, int maxSize)

Method Summary

boolean	acceptReliableMessages() A non-recoverable channel cannot guarantee recoverability for reliable messages so by default it won't accept reliable messages.
void	acknowledge(Delivery d, Transaction tx)
protected void	acknowledgeInternal(Delivery d, Transaction tx, boolean persist)
void	activate()
boolean	add(Receiver r) Add a local receiver to this distributor.
protected void	addReferenceInMemory(MessageReference ref)
java.util.List	browse()
java.util.List	browse(Filter filter)
void	cancel(Delivery del)
protected void	cancelInternal(MessageReference ref)
protected boolean	checkAndSchedule(MessageReference ref)
protected void	checkClosed()
void	clear() Clears non-recoverable state but not persisted state, so a recovery of the channel is possible TODO really?
protected void	clearAllScheduledDeliveries()
void	close() Close the channel
boolean	contains(Receiver r)
void	deactivate()
void	deliver() Delivers as many references as possible to its router until no more deliveries are returned.
protected void	deliverInternal() This methods delivers as many messages as possible to the router until no more deliveries are returned.
protected boolean	deliverScheduled(MessageReference ref)
protected org.jboss.messaging.core.ChannelSupport.InMemoryCallback	getCallback(Transaction tx)
long	getChannelID()
int	getDeliveringCount()
int	getMaxSize()
int	getMessageCount() Returns the count of messages stored AND being delivered AND scheduled
int	getMessagesAdded()
int	getNumberOfReceivers()
int	getScheduledCount() Count scheduled for delivery
Delivery	handle(DeliveryObserver sender, MessageReference ref, Transaction tx) A receiver can return an active, "done" or null delivery.
protected Delivery	handleInternal(DeliveryObserver sender, MessageReference ref, Transaction tx, boolean persist)
boolean	isActive()
boolean	isRecoverable()
java.util.Iterator	iterator()
int	memoryRefCount()
protected void	processMessageBeforeStorage(MessageReference reference) Give subclass a chance to process the message before storing it internally.
java.util.List	recoverDeliveries(java.util.List messageIds)
boolean	remove(Receiver r) Remove a local receiver from this distributor.
void	removeAllReferences() Remove all the references in the channel
protected MessageReference	removeFirstInMemory()
void	setMaxSize(int newSize)
java.lang.String	toString()
java.util.List	undelivered(Filter filter)

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.jboss.messaging.core.Channel

load, unload

Field Detail

channelID

protected long channelID

router

protected Router router

ms

protected MessageStore ms

receiversReady

protected boolean receiversReady

messageRefs

protected PriorityLinkedList messageRefs

acceptReliableMessages

protected boolean acceptReliableMessages

recoverable

protected boolean recoverable

pm

protected PersistenceManager pm

refLock

protected java.lang.Object refLock

active

protected boolean active

deliveringCount

protected SynchronizedInt deliveringCount

scheduledDeliveries

protected java.util.Set scheduledDeliveries

maxSize

protected int maxSize

messagesAdded

protected SynchronizedInt messagesAdded

Constructor Detail

ChannelSupport

protected ChannelSupport(long channelID,
                         MessageStore ms,
                         PersistenceManager pm,
                         boolean acceptReliableMessages,
                         boolean recoverable,
                         int maxSize)

Method Detail

handle

public Delivery handle(DeliveryObserver sender,
                       MessageReference ref,
                       Transaction tx)

Description copied from interface: Receiver

A receiver can return an active, "done" or null delivery. The method returns null in case the receiver doesn't accept the message. The return value is unspecified when the message is submitted in the context of a transaction (tx not null).

Specified by:

handle in interface Receiver

Parameters:

sender - - the component the delivery should be acknowledged to.

See Also:

Delivery, DeliveryObserver

acknowledge

public void acknowledge(Delivery d,
                        Transaction tx)
                 throws java.lang.Throwable

Specified by:

acknowledge in interface DeliveryObserver

Throws:

java.lang.Throwable

cancel

public void cancel(Delivery del)
            throws java.lang.Throwable

Specified by:

cancel in interface DeliveryObserver

Throws:

java.lang.Throwable

add

public boolean add(Receiver r)

Description copied from interface: Distributor

Add a local receiver to this distributor.

Specified by:

add in interface Distributor

Returns:

true if the distributor did not already contain the specified receiver and the receiver was added to the distributor, false otherwise.

remove

public boolean remove(Receiver r)

Description copied from interface: Distributor

Remove a local receiver from this distributor.

Specified by:

remove in interface Distributor

Returns:

true if this distributor contained the specified receiver.

clear

public void clear()

Description copied from interface: Channel

Clears non-recoverable state but not persisted state, so a recovery of the channel is possible TODO really?

Specified by:

clear in interface Channel

contains

public boolean contains(Receiver r)

Specified by:

contains in interface Distributor

iterator

public java.util.Iterator iterator()

Specified by:

iterator in interface Distributor

Returns:

an iterator of local receivers

getNumberOfReceivers

public int getNumberOfReceivers()

Specified by:

getNumberOfReceivers in interface Distributor

Returns:

The number of receivers in the distributor

getChannelID

public long getChannelID()

Specified by:

getChannelID in interface Channel

Returns:

the unique ID of the channel

isRecoverable

public boolean isRecoverable()

Specified by:

isRecoverable in interface Channel

Returns:

true if the channel can guarantee recoverability for reliable messages. Recoverability is not guaranteed for non-reliable messages (and should not be provided by default, for performance reasons), even if the channel is recoverable.

acceptReliableMessages

public boolean acceptReliableMessages()

Description copied from interface: Channel

A non-recoverable channel cannot guarantee recoverability for reliable messages so by default it won't accept reliable messages. However, there are situations when discarding a reliable message is acceptable for a specific instance of a channel, so it should be a way to configure the channel to do so. A channel indicates unequivocally whether it accepts reliable messages or not returning true or false as result of this method. A recoverable channel must always accept reliable messages, so this method must always return true for a recoverable channel.

Specified by:

acceptReliableMessages in interface Channel

Returns:

false if the channel doesn't accept reliable messages.

browse

public java.util.List browse()

Specified by:

browse in interface Channel

Returns:

a List containing messages being held by the channel.

browse

public java.util.List browse(Filter filter)

Specified by:

browse in interface Channel

Parameters:

filter - - may be null, in which case no filter is applied.

Returns:

a List containing message references of messages whose state is maintained by this State instance.

deliver

public void deliver()

Description copied from interface: Channel

Delivers as many references as possible to its router until no more deliveries are returned.

Specified by:

deliver in interface Channel

close

public void close()

Description copied from interface: Channel

Close the channel

Specified by:

close in interface Channel

removeAllReferences

public void removeAllReferences()
                         throws java.lang.Throwable

Description copied from interface: Channel

Remove all the references in the channel

Specified by:

removeAllReferences in interface Channel

Throws:

java.lang.Throwable

undelivered

public java.util.List undelivered(Filter filter)

getMessageCount

public int getMessageCount()

Returns the count of messages stored AND being delivered AND scheduled

Specified by:

getMessageCount in interface Channel

Returns:

Total message count = undelivered + delivering + scheduled

getDeliveringCount

public int getDeliveringCount()

Specified by:

getDeliveringCount in interface Channel

Returns:

Count being delivered

getScheduledCount

public int getScheduledCount()

Description copied from interface: Channel

Count scheduled for delivery

Specified by:

getScheduledCount in interface Channel

activate

public void activate()

Specified by:

activate in interface Channel

deactivate

public void deactivate()

Specified by:

deactivate in interface Channel

isActive

public boolean isActive()

Specified by:

isActive in interface Channel

recoverDeliveries

public java.util.List recoverDeliveries(java.util.List messageIds)

Specified by:

recoverDeliveries in interface Channel

getMaxSize

public int getMaxSize()

Specified by:

getMaxSize in interface Channel

setMaxSize

public void setMaxSize(int newSize)

Specified by:

setMaxSize in interface Channel

getMessagesAdded

public int getMessagesAdded()

Specified by:

getMessagesAdded in interface Channel

memoryRefCount

public int memoryRefCount()

toString

public java.lang.String toString()

clearAllScheduledDeliveries

protected void clearAllScheduledDeliveries()

cancelInternal

protected void cancelInternal(MessageReference ref)
                       throws java.lang.Exception

Throws:

java.lang.Exception

deliverInternal

protected void deliverInternal()

This methods delivers as many messages as possible to the router until no more deliveries are returned. This method should never be called at the same time as handle.

See Also:

Channel.deliver()

deliverScheduled

protected boolean deliverScheduled(MessageReference ref)

handleInternal

protected Delivery handleInternal(DeliveryObserver sender,
                                  MessageReference ref,
                                  Transaction tx,
                                  boolean persist)

checkAndSchedule

protected boolean checkAndSchedule(MessageReference ref)

acknowledgeInternal

protected void acknowledgeInternal(Delivery d,
                                   Transaction tx,
                                   boolean persist)
                            throws java.lang.Exception

Throws:

java.lang.Exception

getCallback

protected org.jboss.messaging.core.ChannelSupport.InMemoryCallback getCallback(Transaction tx)

removeFirstInMemory

protected MessageReference removeFirstInMemory()
                                        throws java.lang.Exception

Throws:

java.lang.Exception

addReferenceInMemory

protected void addReferenceInMemory(MessageReference ref)
                             throws java.lang.Exception

Throws:

java.lang.Exception

processMessageBeforeStorage

protected void processMessageBeforeStorage(MessageReference reference)

Give subclass a chance to process the message before storing it internally. TODO - Do we really need this?

checkClosed

protected void checkClosed()