Document and refactor some connectors-runtime module code

[escay]

Environment Details

• GlassFish Version (and build number): 7.0.14
• JDK version: jdk-17.0.8.1_1-openjdk-adoptium
• OS: Windows 10
• Database: Postgresql

Problem description

• Document (javadoc) some connection pool interfaces in connectors-runtime module to better understand issue NPE in ConnectorXAResource.getResourceHandle causes connection pool problems #24805. With focus on the ResourceHandle fields to understand all fields:
  • com.sun.appserv.connectors.internal.api.ResourceHandle
  • com.sun.enterprise.resource.ResourceHandle
  • com.sun.enterprise.resource.ResourceState
• Refactor some code: remove unused methods, parameters and fields from interfaces.
• Write new unit test to test and understand com.sun.enterprise.resource.pool.PoolManagerImpl mainly regarding state isBusy and state enlisted behaviour of ResourceHandles.

Refactor items like:

ResourceHandle interface: remove destroyResource();
ConnectorConnectionPool: remove resourceSelectionStrategyClass
AssocWithThreadResourceHandle: remove ClientSecurityInfo from constructor
ResourceHandle: change resource and getResource() type from Object to ManagedConnection
 ## (risk if someone made their own implementation)
ResourceHandle: remove ClientSecurityInfo from constructor and field and getter/setter 
 ## (risk if someone made their own implementation)
ResourceHandle: remove subject field and getter/setter
ResourceHandle: remove partition field and getter/setter
ResourceHandle: remove setState setter, set state field immediately so it is never null
ResourceHandle: rename index to rwLockDataStructureResourceIndex
ResourceHandle: rename spec to resourceSpec
ResourceHandle: rename xaRes to xaResource
ResourceHandle: rename supportsLazyEnlistment_ to supportsLazyEnlistment
ResourceHandle: rename supportsLazyAssoc_ to supportsLazyAssociation

ResourceHandle / ResourceState: make ResourceState calls nullpointer safe.

ConnectionPool: remove resourceSelectionStrategyClass
ConnectionPool: rename validation to connectionValidationRequired
ConnectionPool: rename timer to resizerTaskTimer

DataStructureFactory: change parameters of class loading (risk if someone made their own implementation)

ListDataStructure: remove strategyClass from constructor
RWLockDataStructure: remove strategyClass from constructor