Package org.apache.activemq.broker.region

Class PrefetchSubscription

java.lang.Object

org.apache.activemq.broker.region.AbstractSubscription

org.apache.activemq.broker.region.PrefetchSubscription

All Implemented Interfaces:

Subscription, SubscriptionRecovery

Direct Known Subclasses:

DurableTopicSubscription, QueueSubscription

public abstract class PrefetchSubscription
extends AbstractSubscription

A subscription that honors the pre-fetch option of the ConsumerInfo.

Field Summary

Fields

Modifier and Type	Field	Description
protected final List<org.apache.activemq.broker.region.MessageReference>	dispatched
protected final Object	dispatchLock
protected PendingMessageCursor	pending
protected final Object	pendingLock
protected final org.apache.activemq.thread.Scheduler	scheduler
protected final SystemUsage	usageManager

Fields inherited from class org.apache.activemq.broker.region.AbstractSubscription

broker, context, destinationFilter, destinations, info, prefetchExtension

Constructor Summary

Constructors

Constructor	Description
PrefetchSubscription(Broker broker, SystemUsage usageManager, ConnectionContext context, org.apache.activemq.command.ConsumerInfo info)
PrefetchSubscription(Broker broker, SystemUsage usageManager, ConnectionContext context, org.apache.activemq.command.ConsumerInfo info, PendingMessageCursor cursor)

Method Summary

Modifier and Type	Method	Description
final void	acknowledge(ConnectionContext context, org.apache.activemq.command.MessageAck ack)	Used when client acknowledge receipt of dispatched message.
protected abstract void	acknowledge(ConnectionContext context, org.apache.activemq.command.MessageAck ack, org.apache.activemq.broker.region.MessageReference node)	Used during acknowledgment to remove the message.
void	add(ConnectionContext context, Destination destination)	The subscription will be receiving messages from the destination.
void	add(org.apache.activemq.broker.region.MessageReference node)	Used to add messages that match the subscription.
protected void	assertAckMatchesDispatched(org.apache.activemq.command.MessageAck ack)	Checks an ack versus the contents of the dispatched list.
protected abstract boolean	canDispatch(org.apache.activemq.broker.region.MessageReference node)	Use when a matched message is about to be dispatched to the client.
int	countBeforeFull()
protected org.apache.activemq.command.MessageDispatch	createMessageDispatch(org.apache.activemq.broker.region.MessageReference node, org.apache.activemq.command.Message message)
protected boolean	dispatch(org.apache.activemq.broker.region.MessageReference node)
void	dispatchPending()
long	getDequeueCounter()
long	getDispatchedCounter()
int	getDispatchedQueueSize()
long	getEnqueueCounter()
int	getInFlightSize()
int	getMaxAuditDepth()
int	getMaxProducersToAudit()
PendingMessageCursor	getPending()
long	getPendingMessageSize()
int	getPendingQueueSize()
protected abstract boolean	isDropped(org.apache.activemq.broker.region.MessageReference node)
boolean	isFull()	Used to determine if the broker can dispatch to the consumer.
boolean	isHighWaterMark()
boolean	isLowWaterMark()
boolean	isRecoveryRequired()	Informs the Broker if the subscription needs to intervention to recover it's state e.g.
protected void	onDispatch(org.apache.activemq.broker.region.MessageReference node, org.apache.activemq.command.Message message)
void	processMessageDispatchNotification(org.apache.activemq.command.MessageDispatchNotification mdn)	Used by a Slave Broker to update dispatch infomation
org.apache.activemq.command.Response	pullMessage(ConnectionContext context, org.apache.activemq.command.MessagePull pull)	Allows a message to be pulled on demand by a client
List<org.apache.activemq.broker.region.MessageReference>	remove(ConnectionContext context, Destination destination)	The subscription will be no longer be receiving messages from the destination.
List<org.apache.activemq.broker.region.MessageReference>	remove(ConnectionContext context, Destination destination, List<org.apache.activemq.broker.region.MessageReference> dispatched)
protected void	sendToDLQ(ConnectionContext context, org.apache.activemq.broker.region.MessageReference node, Throwable poisonCause)
void	setMaxAuditDepth(int maxAuditDepth)
void	setMaxProducersToAudit(int maxProducersToAudit)
void	setPending(PendingMessageCursor pending)
protected void	setPendingBatchSize(PendingMessageCursor pending, int numberToDispatch)
void	setPrefetchSize(int prefetchSize)
protected boolean	trackedInPendingTransaction(org.apache.activemq.broker.region.MessageReference node)
void	updateConsumerPrefetch(int newPrefetch)	inform the MessageConsumer on the client to change it's prefetch

Methods inherited from class org.apache.activemq.broker.region.AbstractSubscription

addDestination, addRecoveredMessage, contractPrefetchExtension, decrementPrefetchExtension, doAddRecoveredMessage, expandPrefetchExtension, gc, getActiveMQDestination, getConsumedCount, getConsumerInfo, getContext, getCursorMemoryHighWaterMark, getDestinations, getInFlightMessageSize, getInFlightUsage, getInfo, getObjectName, getPrefetchExtension, getPrefetchSize, getSelector, getSelectorExpression, getSubscriptionStatistics, getTimeOfLastMessageAck, incrementConsumedCount, isBrowser, isSlowConsumer, isUsePrefetchExtension, isWildcard, matches, matches, removeDestination, resetConsumedCount, setCursorMemoryHighWaterMark, setObjectName, setSelector, setSlowConsumer, setTimeOfLastMessageAck, setUsePrefetchExtension, unmatched, wakeupDestinationsForDispatch

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.activemq.broker.region.Subscription

destroy

Field Details

scheduler

protected final org.apache.activemq.thread.Scheduler scheduler

pending

protected PendingMessageCursor pending

dispatched

protected final List<org.apache.activemq.broker.region.MessageReference> dispatched

usageManager

protected final SystemUsage usageManager

pendingLock

protected final Object pendingLock

dispatchLock

protected final Object dispatchLock

Constructor Details

PrefetchSubscription

public PrefetchSubscription(Broker broker,
 SystemUsage usageManager,
 ConnectionContext context,
 org.apache.activemq.command.ConsumerInfo info,
 PendingMessageCursor cursor)
                     throws jakarta.jms.JMSException

Throws:

jakarta.jms.JMSException

PrefetchSubscription

public PrefetchSubscription(Broker broker,
 SystemUsage usageManager,
 ConnectionContext context,
 org.apache.activemq.command.ConsumerInfo info)
                     throws jakarta.jms.JMSException

Throws:

jakarta.jms.JMSException

Method Details

pullMessage

public org.apache.activemq.command.Response pullMessage(ConnectionContext context,
 org.apache.activemq.command.MessagePull pull)
                                                 throws Exception

Allows a message to be pulled on demand by a client

Throws:

Exception

add

public void add(org.apache.activemq.broker.region.MessageReference node)
         throws Exception

Description copied from interface: Subscription

Used to add messages that match the subscription.

Throws:

Exception

InterruptedException

IOException

processMessageDispatchNotification

public void processMessageDispatchNotification(org.apache.activemq.command.MessageDispatchNotification mdn)
                                        throws Exception

Description copied from interface: Subscription

Used by a Slave Broker to update dispatch infomation

Throws:

Exception

acknowledge

public final void acknowledge(ConnectionContext context,
 org.apache.activemq.command.MessageAck ack)
                       throws Exception

Description copied from interface: Subscription

Used when client acknowledge receipt of dispatched message.

Specified by:

acknowledge in interface Subscription

Overrides:

acknowledge in class AbstractSubscription

Throws:

IOException

Exception

assertAckMatchesDispatched

protected void assertAckMatchesDispatched(org.apache.activemq.command.MessageAck ack)
                                   throws jakarta.jms.JMSException

Checks an ack versus the contents of the dispatched list. called with dispatchLock held

Parameters:

ack -

Throws:

jakarta.jms.JMSException - if it does not match

sendToDLQ

protected void sendToDLQ(ConnectionContext context,
 org.apache.activemq.broker.region.MessageReference node,
 Throwable poisonCause)
                  throws IOException,
Exception

Parameters:

context -

node -

poisonCause -

Throws:

IOException

Exception

getInFlightSize

public int getInFlightSize()

Returns:

the number of messages awaiting acknowledgement

isFull

public boolean isFull()

Used to determine if the broker can dispatch to the consumer.

Returns:

true if the subscription is full

isLowWaterMark

public boolean isLowWaterMark()

Returns:

true when 60% or more room is left for dispatching messages

isHighWaterMark

public boolean isHighWaterMark()

Returns:

true when 10% or less room is left for dispatching messages

countBeforeFull

public int countBeforeFull()

Specified by:

countBeforeFull in interface Subscription

Overrides:

countBeforeFull in class AbstractSubscription

Returns:

the number of messages this subscription can accept before its full

getPendingQueueSize

public int getPendingQueueSize()

Returns:

number of messages pending delivery

getPendingMessageSize

public long getPendingMessageSize()

Returns:

size of the messages pending delivery

getDispatchedQueueSize

public int getDispatchedQueueSize()

Returns:

number of messages dispatched to the client

getDequeueCounter

public long getDequeueCounter()

Returns:

number of messages queued by the client

getDispatchedCounter

public long getDispatchedCounter()

Returns:

number of messages dispatched to the client

getEnqueueCounter

public long getEnqueueCounter()

Returns:

number of messages that matched the subscription

isRecoveryRequired

public boolean isRecoveryRequired()

Description copied from interface: Subscription

Informs the Broker if the subscription needs to intervention to recover it's state e.g. DurableTopicSubscriber may do

Specified by:

isRecoveryRequired in interface Subscription

Overrides:

isRecoveryRequired in class AbstractSubscription

Returns:

true if recovery required

See Also:

• PendingMessageCursor

getPending

public PendingMessageCursor getPending()

setPending

public void setPending(PendingMessageCursor pending)

add

public void add(ConnectionContext context,
 Destination destination)
         throws Exception

Description copied from interface: Subscription

The subscription will be receiving messages from the destination.

Specified by:

add in interface Subscription

Overrides:

add in class AbstractSubscription

Throws:

Exception

remove

public List<org.apache.activemq.broker.region.MessageReference> remove(ConnectionContext context,
 Destination destination)
                                                                throws Exception

Description copied from interface: Subscription

The subscription will be no longer be receiving messages from the destination.

Specified by:

remove in interface Subscription

Overrides:

remove in class AbstractSubscription

Returns:

a list of un-acked messages that were added to the subscription.

Throws:

Exception

remove

public List<org.apache.activemq.broker.region.MessageReference> remove(ConnectionContext context,
 Destination destination,
 List<org.apache.activemq.broker.region.MessageReference> dispatched)
                                                                throws Exception

Throws:

Exception

dispatchPending

public void dispatchPending()
                     throws IOException

Throws:

IOException

trackedInPendingTransaction

protected boolean trackedInPendingTransaction(org.apache.activemq.broker.region.MessageReference node)

setPendingBatchSize

protected void setPendingBatchSize(PendingMessageCursor pending,
 int numberToDispatch)

dispatch

protected boolean dispatch(org.apache.activemq.broker.region.MessageReference node)
                    throws IOException

Throws:

IOException

onDispatch

protected void onDispatch(org.apache.activemq.broker.region.MessageReference node,
 org.apache.activemq.command.Message message)

updateConsumerPrefetch

public void updateConsumerPrefetch(int newPrefetch)

inform the MessageConsumer on the client to change it's prefetch

Parameters:

newPrefetch -

createMessageDispatch

protected org.apache.activemq.command.MessageDispatch createMessageDispatch(org.apache.activemq.broker.region.MessageReference node,
 org.apache.activemq.command.Message message)

Parameters:

node -

message -

Returns:

MessageDispatch

canDispatch

protected abstract boolean canDispatch(org.apache.activemq.broker.region.MessageReference node)
                                throws IOException

Use when a matched message is about to be dispatched to the client.

Parameters:

node -

Returns:

false if the message should not be dispatched to the client (another sub may have already dispatched it for example).

Throws:

IOException

isDropped

protected abstract boolean isDropped(org.apache.activemq.broker.region.MessageReference node)

acknowledge

protected abstract void acknowledge(ConnectionContext context,
 org.apache.activemq.command.MessageAck ack,
 org.apache.activemq.broker.region.MessageReference node)
                             throws IOException

Used during acknowledgment to remove the message.

Throws:

IOException

getMaxProducersToAudit

public int getMaxProducersToAudit()

setMaxProducersToAudit

public void setMaxProducersToAudit(int maxProducersToAudit)

getMaxAuditDepth

public int getMaxAuditDepth()

setMaxAuditDepth

public void setMaxAuditDepth(int maxAuditDepth)

setPrefetchSize

public void setPrefetchSize(int prefetchSize)

Overrides:

setPrefetchSize in class AbstractSubscription