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PlantUML

skinparam dpi 80

@startuml
hide empty members
title Server to Client Queues - Class Diagram
class CacheClientNotifier {
  Singleton for a Cache.
}
class CacheClientProxy {
  One for each client.
  Keeps track of a the subscriptions for the client.
}
class MessageDispatcher {
  Thread that reads events from the queue.
}
class HARegionQueue {
  Holds the list of events to
  dispatch to a single client.
}
class HAContainerMap {
  Holds the actual values for events to dispatch.
  Used to store only a single copy of each value
  across all queues.
}
interface HAContainerMap
CacheClientNotifier "1   " o-- "*" CacheClientProxy
CacheClientProxy o-- MessageDispatcher
CacheClientNotifier o-- HAContainerMap
MessageDispatcher o-- HARegionQueue
HARegionQueue "*" --> "1" HAContainerMap
HARegionQueue o-- HARegion
@enduml

This next diagram focuses on cardinality:

between HARegionQueue and DACE (DispatchedAndCurrentEvents) objects (through the mis-named HARegionQueue.eventsMap)
between HARegion and the two kinds of entries it holds: <Position,Conflatable> and <ThreadIdentifier,SequenceID>

In both cases, the Java Maps are depicted as associations in the diagram (the Map objects are not shown explicitly). So, for instance HARegionQueue.eventsMap is a Map. It's depicted as a 1-to-(0..1 per Position) association from HARegionQueue to Position. Similarly for HARegion to Conflatable and HARegion to SequenceID.

The diagram introduces two types not actually present in the Java code. Both are depicted as subtypes of Long: SequenceID to stand for an event's sequence id; and Position to stand for a position in a queue. In the source code these are both just Longs.

PlantUML

@startuml

title HARegionQueue—Class Diagram\nHARegion and DACE Cardinalities

class SequenceID <<design class>>
Long <|-- SequenceID
class Position <<design class>>
Long <|-- Position

class HARegionQueue {
  Position tailKey
}

class DispatchedAndCurrentEvents {
 SequenceID lastDispatchedSequenceID
}

' these are together because I want to highlight the similarity (potential subtype relationship)
together {

  ' putting this first causes it to be layed out to the right of ThreadIdentifier, making the
  ' association (line) from Conflatable shorter
  class EventID {
    byte[]     membershipId
    long       threadId
    SequenceID sequenceId
    int        bucketId
  }

  class ThreadIdentifier {
    byte[]     membershipId
    long       threadId
  }
}

interface Conflatable

' these subtypes of Conflatable are grouped together
together {
  interface ClientMessage
  class HAEventWrapper
  class ConflatableObject
}

Conflatable <|-- HAEventWrapper

Conflatable <|-- ConflatableObject

Conflatable <|-- ClientMessage

interface ClientUpdateMessage

ClientMessage <|-- ClientUpdateMessage
ClientUpdateMessage <|-- ClientUpdateMessageImpl
ClientUpdateMessageImpl <|-- ClientInstantiatorMessage


ClientMessage <|-- ClientMarkerMessageImpl

Conflatable --> EventID

interface RegionQueue
RegionQueue <|-- HARegionQueue
HARegionQueue <|-- BlockingHARegionQueue
BlockingHARegionQueue <|-- DurableHARegionQueue
DistributedRegion <|-- HARegion

' while method signatures in HARegionQueue take Object, there's downcasting to Conflatable
HARegion "*" *-- "0..1 per Position" Conflatable

HARegion "*" *-- "0..1 per ThreadIdentifier" SequenceID

HARegionQueue *-- HARegion

HARegionQueue "1" *-- "0..1 per ThreadIdentifier" DispatchedAndCurrentEvents

DispatchedAndCurrentEvents "1" *-- "0..1 per Position" Position

' this hidden assoc changes layout such that cardinality text on SequenceID and Position isn't overlapping as much
ConflatableObject -[hidden]- HARegion

@enduml

...

1. The server is providing an initial image to a performed (see HARegionQueue.giiQueue)
2. The server A client is initializing in the process of registering and its message dispatcher as part of cliesnt queue initialization logic (see CacheClientProxy.queuedEvents)/queue are not fully created and initialized

After these operations are completed, the temporary queues are drained and the event is added to the HARegionQueue. The diagrams below show the different put paths in detail.

Image RemovedImage Added