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MessageCache (JBoss Messaging API) - JBoss 4.0.1 sp1 messaging API Documentation 英文版文档

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org.jboss.mq.server
Class MessageCache

java.lang.Object
  org.jboss.mx.util.JBossNotificationBroadcasterSupport
      org.jboss.system.ServiceMBeanSupport
          org.jboss.mq.server.MessageCache

All Implemented Interfaces:

javax.management.MBeanRegistration, MessageCacheMBean, javax.management.NotificationBroadcaster, javax.management.NotificationEmitter, Runnable, org.jboss.system.Service, org.jboss.system.ServiceMBean

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public class MessageCache

extends org.jboss.system.ServiceMBeanSupport

implements MessageCacheMBean, javax.management.MBeanRegistration, Runnable

This class implements a Message cache so that larger amounts of messages can be processed without running out of memory. When memory starts getting tight it starts moving messages out of memory and into a file so that they can be recovered later. The locks should be obtained in the following order:
mr, the relevent message we are working with
lruCache, when maintaining the usage order

Version:

$Revision: 1.31 $

Author:

Hiram Chirino, David Maplesden, Peter Antman, Adrian Brock

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Field Summary
static long	DEFAULT_HIGH_MEMORY_MARK
static long	DEFAULT_MAX_MEMORY_MARK
static long	ONE_MEGABYTE

 

Fields inherited from class org.jboss.system.ServiceMBeanSupport

log, server, SERVICE_CONTROLLER_SIG, serviceName

 

Fields inherited from interface org.jboss.mq.server.MessageCacheMBean

OBJECT_NAME

 

Fields inherited from interface org.jboss.system.ServiceMBean

CREATE_EVENT, CREATED, DESTROY_EVENT, DESTROYED, FAILED, REGISTERED, START_EVENT, STARTED, STARTING, states, STOP_EVENT, STOPPED, STOPPING, UNREGISTERED

 

Constructor Summary

MessageCache()

 

Method Summary
MessageReference	add(SpyMessage message)           Adds a message to the cache
MessageReference	add(SpyMessage message, BasicQueue queue, int stored)           Adds a message to the cache.
MessageReference	add(SpyMessage message, BasicQueue queue, int stored, DurableSubscriptionID id)           Adds a message to the cache.
MessageReference	addInternal(SpyMessage message, BasicQueue queue, int stored, DurableSubscriptionID id)           Adds a message to the cache.
long	getCacheHits()           Gets the cacheHits
long	getCacheMisses()           Gets the cacheMisses
javax.management.ObjectName	getCacheStore()           The getCacheStore method
long	getCurrentMemoryUsage()           Gets the CurrentMemoryUsage
int	getHardRefCacheSize()           Gets the hardRefCacheSize
long	getHighMemoryMark()           Gets the highMemoryMark
MessageCache	getInstance()           The getInstance method
boolean	getMakeSoftReferences()           Gets whether to make soft references
int	getMaximumHard()           Gets the maximum number of hard messages
long	getMaxMemoryMark()           Gets the maxMemoryMark
int	getMinimumHard()           Gets the minimum number of hard messages
String	getName()
long	getSoftenAtLeastEveryMillis()           Gets the maximum length between softening checks
long	getSoftenedSize()           The getSoftenedSize method
long	getSoftenNoMoreOftenThanMillis()           Gets the minimum length between softening checks
long	getSoftenWaitMillis()           Gets the length of time to wait before checking whether we should soften
int	getSoftRefCacheSize()           Gets the softRefCacheSize
int	getTotalCacheSize()           Gets the totalCacheSize
void	remove(MessageReference mr)           removes a message from the cache
void	removeDelayed(MessageReference mr)           removes a message from the cache without returning it to the pool used in two phase removes for joint cache/persistence
protected  void	removeInternal(MessageReference mr, boolean clear, boolean reset)           removes a message from the cache
void	run()           The strategy is that we keep the most recently used messages as Hard references.
void	setCacheStore(javax.management.ObjectName cacheStoreName)
void	setHighMemoryMark(long highMemoryMark)           Sets the highMemoryMark
void	setMakeSoftReferences(boolean makeSoftReferences)           Sets whether to make soft references
void	setMaximumHard(int maximumHard)           Sets the maximum number of hard messages
void	setMaxMemoryMark(long maxMemoryMark)           Sets the maxMemoryMark
void	setMinimumHard(int minimumHard)           Sets the minimum number of hard messages
void	setSoftenAtLeastEveryMillis(long millis)           Sets the minimum length between softening checks
void	setSoftenNoMoreOftenThanMillis(long millis)           Sets the minimum length between softening checks
void	setSoftenWaitMillis(long millis)           Sets the length of time to wait before checking whether we should soften
protected  void	startService()           This gets called to start the cache service.
protected  void	stopService()           This gets called to stop the cache service.

 

Methods inherited from class org.jboss.system.ServiceMBeanSupport

create, createService, destroy, destroyService, getLog, getNextNotificationSequenceNumber, getObjectName, getServer, getServiceName, getState, getStateString, jbossInternalCreate, jbossInternalDescription, jbossInternalDestroy, jbossInternalLifecycle, jbossInternalStart, jbossInternalStop, postDeregister, postRegister, preDeregister, preRegister, start, stop

 

Methods inherited from class org.jboss.mx.util.JBossNotificationBroadcasterSupport

addNotificationListener, getNotificationInfo, handleNotification, removeNotificationListener, removeNotificationListener, sendNotification

 

Methods inherited from class java.lang.Object

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

 

Methods inherited from interface org.jboss.system.ServiceMBean

getState, getStateString, jbossInternalLifecycle

 

Methods inherited from interface org.jboss.system.Service

create, destroy, start, stop

 

Methods inherited from interface javax.management.MBeanRegistration

postDeregister, postRegister, preDeregister, preRegister

 

Field Detail

ONE_MEGABYTE

public static final long ONE_MEGABYTE

See Also:

Constant Field Values

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DEFAULT_HIGH_MEMORY_MARK

public static final long DEFAULT_HIGH_MEMORY_MARK

See Also:

Constant Field Values

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DEFAULT_MAX_MEMORY_MARK

public static final long DEFAULT_MAX_MEMORY_MARK

See Also:

Constant Field Values

Constructor Detail

MessageCache

public MessageCache()

Method Detail

getInstance

public MessageCache getInstance()

The getInstance method

Specified by:

getInstance in interface MessageCacheMBean

Returns:

a MessageCache value

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add

public MessageReference add(SpyMessage message)
                     throws javax.jms.JMSException

Adds a message to the cache

Throws:

javax.jms.JMSException

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add

public MessageReference add(SpyMessage message,
                            BasicQueue queue,
                            int stored)
                     throws javax.jms.JMSException

Adds a message to the cache.

Throws:

javax.jms.JMSException

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add

public MessageReference add(SpyMessage message,
                            BasicQueue queue,
                            int stored,
                            DurableSubscriptionID id)
                     throws javax.jms.JMSException

Adds a message to the cache.

Throws:

javax.jms.JMSException

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addInternal

public MessageReference addInternal(SpyMessage message,
                                    BasicQueue queue,
                                    int stored,
                                    DurableSubscriptionID id)
                             throws javax.jms.JMSException

Adds a message to the cache.

Throws:

javax.jms.JMSException

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remove

public void remove(MessageReference mr)
            throws javax.jms.JMSException

removes a message from the cache

Throws:

javax.jms.JMSException

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removeDelayed

public void removeDelayed(MessageReference mr)
                   throws javax.jms.JMSException

removes a message from the cache without returning it to the pool used in two phase removes for joint cache/persistence

Throws:

javax.jms.JMSException

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removeInternal

protected void removeInternal(MessageReference mr,
                              boolean clear,
                              boolean reset)
                       throws javax.jms.JMSException

removes a message from the cache

Throws:

javax.jms.JMSException

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run

public void run()

The strategy is that we keep the most recently used messages as Hard references. Then we make the older ones soft references. Making something a soft reference stores it to disk so we need to avoid making soft references if we can avoid it. But once it is made a soft reference does not mean that it is removed from memory. Depending on how agressive the JVM's GC is, it may stay around long enough for it to be used by a client doing a read, saving us read from the file system. If memory gets tight the GC will remove the soft references. What we want to do is make sure there are at least some soft references available so that the GC can reclaim memory.

Specified by:

run in interface Runnable

See Also:

Runnable.run()

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startService

protected void startService()
                     throws Exception

This gets called to start the cache service. Synch. by start

Throws:

Exception

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stopService

protected void stopService()

This gets called to stop the cache service.

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getHardRefCacheSize

public int getHardRefCacheSize()

Gets the hardRefCacheSize

Specified by:

getHardRefCacheSize in interface MessageCacheMBean

Returns:

Returns a int

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getSoftenedSize

public long getSoftenedSize()

The getSoftenedSize method

Specified by:

getSoftenedSize in interface MessageCacheMBean

Returns:

a long value

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getSoftRefCacheSize

public int getSoftRefCacheSize()

Gets the softRefCacheSize

Specified by:

getSoftRefCacheSize in interface MessageCacheMBean

Returns:

Returns a int

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getTotalCacheSize

public int getTotalCacheSize()

Gets the totalCacheSize

Specified by:

getTotalCacheSize in interface MessageCacheMBean

Returns:

Returns a int

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getCacheMisses

public long getCacheMisses()

Gets the cacheMisses

Specified by:

getCacheMisses in interface MessageCacheMBean

Returns:

Returns a int

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getCacheHits

public long getCacheHits()

Gets the cacheHits

Specified by:

getCacheHits in interface MessageCacheMBean

Returns:

Returns a long

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getMakeSoftReferences

public boolean getMakeSoftReferences()

Gets whether to make soft references

Specified by:

getMakeSoftReferences in interface MessageCacheMBean

Returns:

true when making soft references

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setMakeSoftReferences

public void setMakeSoftReferences(boolean makeSoftReferences)

Sets whether to make soft references

Specified by:

setMakeSoftReferences in interface MessageCacheMBean

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getMinimumHard

public int getMinimumHard()

Gets the minimum number of hard messages

Specified by:

getMinimumHard in interface MessageCacheMBean

Returns:

the minimum number of hard messages

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setMinimumHard

public void setMinimumHard(int minimumHard)

Sets the minimum number of hard messages

Specified by:

setMinimumHard in interface MessageCacheMBean

Parameters:

minimumHard - the minimum number of hard messages

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getMaximumHard

public int getMaximumHard()

Gets the maximum number of hard messages

Specified by:

getMaximumHard in interface MessageCacheMBean

Returns:

the minimum number of hard messages

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setMaximumHard

public void setMaximumHard(int maximumHard)

Sets the maximum number of hard messages

Specified by:

setMaximumHard in interface MessageCacheMBean

Parameters:

maximumHard - the maximum number of hard messages

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getSoftenWaitMillis

public long getSoftenWaitMillis()

Gets the length of time to wait before checking whether we should soften

Specified by:

getSoftenWaitMillis in interface MessageCacheMBean

Returns:

the time to wait

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setSoftenWaitMillis

public void setSoftenWaitMillis(long millis)

Sets the length of time to wait before checking whether we should soften

Specified by:

setSoftenWaitMillis in interface MessageCacheMBean

Parameters:

millis - the time to wait in millis

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getSoftenNoMoreOftenThanMillis

public long getSoftenNoMoreOftenThanMillis()

Gets the minimum length between softening checks

Specified by:

getSoftenNoMoreOftenThanMillis in interface MessageCacheMBean

Returns:

the time to wait

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setSoftenNoMoreOftenThanMillis

public void setSoftenNoMoreOftenThanMillis(long millis)

Sets the minimum length between softening checks

Specified by:

setSoftenNoMoreOftenThanMillis in interface MessageCacheMBean

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getSoftenAtLeastEveryMillis

public long getSoftenAtLeastEveryMillis()

Gets the maximum length between softening checks

Specified by:

getSoftenAtLeastEveryMillis in interface MessageCacheMBean

Returns:

the time

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setSoftenAtLeastEveryMillis

public void setSoftenAtLeastEveryMillis(long millis)

Sets the minimum length between softening checks

Specified by:

setSoftenAtLeastEveryMillis in interface MessageCacheMBean

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getHighMemoryMark

public long getHighMemoryMark()

Gets the highMemoryMark

Specified by:

getHighMemoryMark in interface MessageCacheMBean

Returns:

Returns a long

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setHighMemoryMark

public void setHighMemoryMark(long highMemoryMark)

Sets the highMemoryMark

Specified by:

setHighMemoryMark in interface MessageCacheMBean

Parameters:

highMemoryMark - The highMemoryMark to set

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getMaxMemoryMark

public long getMaxMemoryMark()

Gets the maxMemoryMark

Specified by:

getMaxMemoryMark in interface MessageCacheMBean

Returns:

Returns a long

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setMaxMemoryMark

public void setMaxMemoryMark(long maxMemoryMark)

Sets the maxMemoryMark

Specified by:

setMaxMemoryMark in interface MessageCacheMBean

Parameters:

maxMemoryMark - The maxMemoryMark to set

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getCurrentMemoryUsage

public long getCurrentMemoryUsage()

Gets the CurrentMemoryUsage

Specified by:

getCurrentMemoryUsage in interface MessageCacheMBean

Returns:

Returns a long

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getName

public String getName()

Specified by:

getName in interface org.jboss.system.ServiceMBean

See Also:

ServiceMBeanSupport.getName()

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setCacheStore

public void setCacheStore(javax.management.ObjectName cacheStoreName)

Specified by:

setCacheStore in interface MessageCacheMBean

See Also:

MessageCacheMBean.setCacheStore(ObjectName)

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getCacheStore

public javax.management.ObjectName getCacheStore()

The getCacheStore method

Specified by:

getCacheStore in interface MessageCacheMBean

Returns:

an ObjectName value

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SUMMARY: NESTED | FIELD | CONSTR | METHOD	DETAIL: FIELD | CONSTR | METHOD

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