org.jboss.messaging.core.impl
Class PagingChannelSupport

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

All Implemented Interfaces:

Channel, DeliveryObserver, Receiver

Direct Known Subclasses:

MessagingQueue

public abstract class PagingChannelSupport
extends ChannelSupport

This channel implementation automatically pages message references to and from storage to prevent more than a maximum number of references being stored in memory at once. This allows us to support logical channels holding many millions of messages without running out of memory.

Version:

$Revision: 3132 $ $Id: PagingChannelSupport.java 3132 2007-09-21 11:06:17Z timfox $

Author:

Tim Fox

Field Summary

protected java.util.List	downCache
protected int	downCacheSize The maximum number of references paged to storage in one operation
protected long	firstPagingOrder The page order value for the first reference paged in storage
protected int	fullSize The maximum number of references this channel will hold before going into paging mode
protected MessageStore	ms
protected long	nextPagingOrder The value of page order for the next reference to page
protected int	pageSize The maximum number of references to load from storage in one go when unpaging
protected boolean	paging Are we in paging mode?

Fields inherited from class org.jboss.messaging.core.impl.ChannelSupport

active, channelID, deliveringCount, distributor, lock, maxSize, messageRefs, messagesAdded, pm, receiversReady, recoverable, scheduledDeliveries

Constructor Summary

PagingChannelSupport(long channelID, MessageStore ms, PersistenceManager pm, boolean recoverable, int maxSize)
Constructor with default paging params.

PagingChannelSupport(long channelID, MessageStore ms, PersistenceManager pm, boolean recoverable, int maxSize, int fullSize, int pageSize, int downCacheSize)
Constructor specifying paging params.

Method Summary

protected MessageReference	addFromRefInfo(PersistenceManager.ReferenceInfo info, java.util.Map refMap)
protected void	addReferenceInMemory(MessageReference ref)
protected void	addToDownCache(MessageReference ref, boolean cancelling)
protected void	cancelInternal(MessageReference ref)
protected void	doLoad(PersistenceManager.InitialLoadInfo ili)
int	downCacheCount()
protected void	flushDownCache()
int	getMessageCount() Returns the count of messages stored AND being delivered AND scheduled
boolean	isPaging()
void	load() Load any references for this channel from storage
protected void	loadPagedReferences(int number)
protected java.util.Map	processReferences(java.util.List refInfos)
protected MessageReference	removeFirstInMemory()
void	setPagingParams(int fullSize, int pageSize, int downCacheSize)
void	unload() Unload any references for this channel

Methods inherited from class org.jboss.messaging.core.impl.ChannelSupport

acknowledge, acknowledgeInternal, activate, browse, cancel, checkAndSchedule, checkClosed, clearAllScheduledDeliveries, close, deactivate, deliver, deliverInternal, deliverScheduled, getCallback, getChannelID, getDeliveringCount, getMaxSize, getMessagesAdded, getReceiversReady, getScheduledCount, handle, handleInternal, isActive, isRecoverable, memoryRefCount, processMessageBeforeStorage, removeAllReferences, setMaxSize, setReceiversReady, undelivered

Methods inherited from class java.lang.Object

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

Field Detail

downCache

protected java.util.List downCache

fullSize

protected int fullSize

The maximum number of references this channel will hold before going into paging mode

pageSize

protected int pageSize

The maximum number of references to load from storage in one go when unpaging

downCacheSize

protected int downCacheSize

The maximum number of references paged to storage in one operation

paging

protected boolean paging

Are we in paging mode?

firstPagingOrder

protected long firstPagingOrder

The page order value for the first reference paged in storage

nextPagingOrder

protected long nextPagingOrder

The value of page order for the next reference to page

ms

protected MessageStore ms

Constructor Detail

PagingChannelSupport

public PagingChannelSupport(long channelID,
                            MessageStore ms,
                            PersistenceManager pm,
                            boolean recoverable,
                            int maxSize)

Constructor with default paging params.

PagingChannelSupport

public PagingChannelSupport(long channelID,
                            MessageStore ms,
                            PersistenceManager pm,
                            boolean recoverable,
                            int maxSize,
                            int fullSize,
                            int pageSize,
                            int downCacheSize)

Constructor specifying paging params.

Method Detail

getMessageCount

public int getMessageCount()

Description copied from class: ChannelSupport

Returns the count of messages stored AND being delivered AND scheduled

Specified by:

getMessageCount in interface Channel

Overrides:

getMessageCount in class ChannelSupport

Returns:

Total message count = undelivered + delivering + scheduled

downCacheCount

public int downCacheCount()

isPaging

public boolean isPaging()

setPagingParams

public void setPagingParams(int fullSize,
                            int pageSize,
                            int downCacheSize)

load

public void load()
          throws java.lang.Exception

Description copied from interface: Channel

Load any references for this channel from storage

Throws:

java.lang.Exception

unload

public void unload()
            throws java.lang.Exception

Description copied from interface: Channel

Unload any references for this channel

Throws:

java.lang.Exception

loadPagedReferences

protected void loadPagedReferences(int number)
                            throws java.lang.Exception

Throws:

java.lang.Exception

cancelInternal

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

Overrides:

cancelInternal in class ChannelSupport

Throws:

java.lang.Exception

removeFirstInMemory

protected MessageReference removeFirstInMemory()
                                        throws java.lang.Exception

Overrides:

removeFirstInMemory in class ChannelSupport

Throws:

java.lang.Exception

addReferenceInMemory

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

Overrides:

addReferenceInMemory in class ChannelSupport

Throws:

java.lang.Exception

addToDownCache

protected void addToDownCache(MessageReference ref,
                              boolean cancelling)
                       throws java.lang.Exception

Throws:

java.lang.Exception

flushDownCache

protected void flushDownCache()
                       throws java.lang.Exception

Throws:

java.lang.Exception

doLoad

protected void doLoad(PersistenceManager.InitialLoadInfo ili)
               throws java.lang.Exception

Throws:

java.lang.Exception

addFromRefInfo

protected MessageReference addFromRefInfo(PersistenceManager.ReferenceInfo info,
                                          java.util.Map refMap)

processReferences

protected java.util.Map processReferences(java.util.List refInfos)
                                   throws java.lang.Exception

Throws:

java.lang.Exception