org.apache.pulsar.broker.service

Class AbstractDispatcherMultipleConsumers

java.lang.Object

org.apache.pulsar.broker.service.AbstractBaseDispatcher

org.apache.pulsar.broker.service.AbstractDispatcherMultipleConsumers

All Implemented Interfaces:

Dispatcher

Direct Known Subclasses:

NonPersistentDispatcherMultipleConsumers, PersistentDispatcherMultipleConsumers

public abstract class AbstractDispatcherMultipleConsumers
extends AbstractBaseDispatcher

Field Summary

Fields

Modifier and Type	Field and Description
protected CopyOnWriteArrayList<Consumer>	consumerList
protected com.carrotsearch.hppc.ObjectSet<Consumer>	consumerSet
protected int	currentConsumerRoundRobinIndex
protected static int	FALSE
protected static AtomicIntegerFieldUpdater<AbstractDispatcherMultipleConsumers>	IS_CLOSED_UPDATER
protected static int	TRUE

Fields inherited from class org.apache.pulsar.broker.service.AbstractBaseDispatcher

serviceConfig, subscription

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AbstractDispatcherMultipleConsumers(Subscription subscription, ServiceConfiguration serviceConfig)

Method Summary

Modifier and Type	Method and Description
protected void	cancelPendingRead()
boolean	canUnsubscribe(Consumer consumer)
CopyOnWriteArrayList<Consumer>	getConsumers()
Consumer	getNextConsumer() Broker gives more priority while dispatching messages.
Consumer	getRandomConsumer() Get random consumer from consumerList.
org.apache.pulsar.common.api.proto.CommandSubscribe.SubType	getType()
boolean	isClosed()
abstract boolean	isConsumerAvailable(Consumer consumer)
boolean	isConsumerConnected()

Methods inherited from class org.apache.pulsar.broker.service.AbstractBaseDispatcher

computeReadLimits, filterEntriesForConsumer, filterEntriesForConsumer, isConsumersExceededOnSubscription, isConsumersExceededOnSubscription, peekStickyKey, resetCloseFuture, updateEntryWrapperWithMetadata

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.pulsar.broker.service.Dispatcher

addConsumer, addUnAckedMessages, checkAndUnblockIfStuck, clearDelayedMessages, close, consumerFlow, cursorIsReset, disconnectActiveConsumers, disconnectAllConsumers, disconnectAllConsumers, getNumberOfDelayedMessages, getRateLimiter, getRedeliveryTracker, initializeDispatchRateLimiterIfNeeded, markDeletePositionMoveForward, redeliverUnacknowledgedMessages, redeliverUnacknowledgedMessages, removeConsumer, reset, trackDelayedDelivery, updateRateLimiter

Field Detail

consumerList

protected final CopyOnWriteArrayList<Consumer> consumerList

consumerSet

protected final com.carrotsearch.hppc.ObjectSet<Consumer> consumerSet

currentConsumerRoundRobinIndex

protected volatile int currentConsumerRoundRobinIndex

FALSE

protected static final int FALSE

See Also:

Constant Field Values

TRUE

protected static final int TRUE

See Also:

Constant Field Values

IS_CLOSED_UPDATER

protected static final AtomicIntegerFieldUpdater<AbstractDispatcherMultipleConsumers> IS_CLOSED_UPDATER

Constructor Detail

AbstractDispatcherMultipleConsumers

protected AbstractDispatcherMultipleConsumers(Subscription subscription,
                                              ServiceConfiguration serviceConfig)

Method Detail

isConsumerConnected

public boolean isConsumerConnected()

getConsumers

public CopyOnWriteArrayList<Consumer> getConsumers()

canUnsubscribe

public boolean canUnsubscribe(Consumer consumer)

isClosed

public boolean isClosed()

getType

public org.apache.pulsar.common.api.proto.CommandSubscribe.SubType getType()

isConsumerAvailable

public abstract boolean isConsumerAvailable(Consumer consumer)

cancelPendingRead

protected void cancelPendingRead()

getNextConsumer

public Consumer getNextConsumer()

 Broker gives more priority while dispatching messages. Here, broker follows descending priorities. (eg:
 0=max-priority, 1, 2,..)
 

 Broker will first dispatch messages to max priority-level consumers if they
 have permits, else broker will consider next priority level consumers.
 Also on the same priority-level, it selects consumer in round-robin manner.
 

 If subscription has consumer-A with  priorityLevel 1 and Consumer-B with priorityLevel 2
 then broker will dispatch
 messages to only consumer-A until it runs out permit and then broker starts dispatching messages to Consumer-B.
 

 Consumer PriorityLevel Permits
 C1       0             2
 C2       0             1
 C3       0             1
 C4       1             2
 C5       1             1
 Result of getNextConsumer(): C1, C2, C3, C1, C4, C5, C4
 

 Algorithm:
 1. consumerList: it stores consumers in sorted-list: max-priority stored first
 2. currentConsumerRoundRobinIndex: it always stores last served consumer-index

 Each time getNextConsumer() is called:

 1. It always starts to traverse from the max-priority consumer (first element) from sorted-list
 2. Consumers on same priority-level will be treated equally and it tries to pick one of them in
    round-robin manner
 3. If consumer is not available on given priority-level then only it will go to the next lower priority-level
    consumers
 4. Returns null in case it doesn't find any available consumer
 

Returns:

nextAvailableConsumer

getRandomConsumer

public Consumer getRandomConsumer()

Get random consumer from consumerList.

Returns:

null if no consumer available, else return random consumer from consumerList