Package org.apache.pulsar.broker.service

Class AbstractDispatcherMultipleConsumers

java.lang.Object
org.apache.pulsar.broker.service.EntryFilterSupport
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 Details

  • Constructor Details

    • AbstractDispatcherMultipleConsumers

      protected AbstractDispatcherMultipleConsumers(Subscription subscription, org.apache.pulsar.broker.ServiceConfiguration serviceConfig)

  • Method Details

    • 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