Overview

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The goal of this proposal is to define clear lines between modules of geode. The goal of is that each module should

1. Be mockable - so that that other modules can write tests that don't depend on that module
2. Be tested within the module. In other words, if WAN depends on the Region module, I should not need to run any WAN tests to test all of the Code in LocalRegion.

 

In order to accomplish these goals, each module needs to have a clear API for the rest of the system to use, and tests within that module that cover all of the features of the API. Each module should have at least it's own package(s), if not be in a separate gradle module. Anything that is not part of the API for that module should only not be accessible outside of the module. 

Here's a start at listing the proposed modules and their dependencies. This is not the current state of these modules because currently there are several cyclical dependencies (eg Persistence dependencies on Regions, regions depend on persistence)These are proposed dependencies, their currently there many cyclical dependencies. Part of the effort here will be to break some of these cyclic dependencies by replacing hardcoded hard coded references to other modules with plugins and callbacks that are part of the well defined API for each module.

 

PlantUML

@startuml title Geode Package Dependency Graph hide members hide circle @startuml title Geode Package Dependency Graph hide members hide circle package Core { } Extensions-->Core Rest-->Management Gfsh-->Management Management-->Core Core-->BasePackages class Management package Extensions { class Redis class MemcacheD class SpringDataGemfire class HttpSession class Hibernate class Spark class Lucene } package BasePackages { class Statistics class Logging class Serialization class Events } @enduml

PlantUML

@startuml title Geode Core Package Dependency Graph hide members hide circle class WAN CacheServer-->Messaging Client-->Locator ClientSubscriptions-->Regions ClientSubscriptions-->CacheServer ClientSubscriptions-->Client DLock-->Messaging FunctionService-->Messaging FunctionServiceclass WAN CacheServer-->Messaging CacheServer-->Statistics Client-->Statistics FunctionService-->Messaging FunctionService-->Regions FunctionService-->Serialization FunctionService-->Statistics Messaging-->Serialization Messaging-->Statistics OffHeap-->Serialization OffHeap-->Statistics PDX-->Messaging PDX-->Regions PDX-->Serialization>Messaging PDX-->Statistics>Regions Persistence-->Serialization>Versioning Persistence-->Statistics Querying -> Messaging Querying-->Regions Querying--> Serialization>Indexing QueryingMessaging-->Statistics>Locator Regions-->CacheServer Regions-->Client Regions-->DLock Regions-->Messaging Regions-->OffHeap Regions-->Persistence Regions-->ResourceManager Regions--> Serialization>Eviction Regions-->Statistics>Versioning RegionsSnapshots-->Statistics>Regions ResourceManagerSnapshots-->OffHeap>FunctionService ResourceManager-->Serialization ResourceManager-->Statistics Serialization-->Statistics>OffHeap WAN-->CacheServer WAN-->Client WAN-->Messaging WAN-->Regions WAN-->Serialization>Locator WAN-->Statistics @enduml

Packages

Client

Package: internal.cache.client

API interfaces/classes: AbstractOp, ExecutablePool

Required Changes: Operations (The client side code for client-> server messages) for other modules should be moved to their respective packages.

ClientSubscriptions

Package:internal.cache.ha (change this?)

API interface/classes: ?

Required changes: ?

DLock

Package:internal.locks

API interface/classes: InternalDistributedLockService (new interface)

Required changes: ?

Events

Package: internal.cache.event (new package)

API interface/classes: 

Below is a high level view of the interfaces for each module and some of the changes that need to be made to get to this point.

InternalEntryEvent. RegionEntry

Required changes: ? These events are passed everywhere, which is why it would be nice to refactor this code into a separate package that other packages can depend on.

Eviction

Package: internal.cache.lru

API interface/classes: EnableLRU, LRUClockHand (new interface)

Required changes: ?

FunctionService

Package: internal.cache.execute

API interfaces/classes: FunctionService, Execution, Function

Required changes: Region code should be refactored to not have direct dependencies on this package. For example, LocalRegion should not have function execution code in it.

Indexing

Package: query.internal.index

API interface/classes: ?

Required changes: ?

Locator

Package: distributed.internal.tcpserver

API interface/classes: TcpHandler, ?

 Required changes: ?

Messaging

Package:distributed.internainternal, distributed.internal.advisor

...

@startuml
title Messaging Packages
hide members
hide circle
class Messaging
package OtherComponents {
  class Regions
  class WAN
}
Advisors --> Messaging
Messaging --> Membership
OtherComponents --> Advisors
OtherComponents --> Messaging
@enduml