com.goldencode.p2j.persist

Class TemporaryBuffer.Context

java.lang.Object

com.goldencode.p2j.persist.TemporaryBuffer.Context

All Implemented Interfaces:

SessionListener

Enclosing class:

TemporaryBuffer

private static class TemporaryBuffer.Context
extends java.lang.Object
implements SessionListener

Helper which tracks the multiplex IDs currently in use by DMO interface in the current client context, as well as the reference count of temp tables created in the database using the context's current connection, and domains of master/slave buffers.

This object also tracks tables which have been created during the current database session, and drops them when the session is being closed. This is done as an optimization to prevent potential thrashing in the event a class which creates a temporary buffer and then allows it to go out of scope is invoked repeatedly in a loop.

Nested Class Summary

Nested classes/interfaces inherited from interface com.goldencode.p2j.persist.event.SessionListener

SessionListener.Event, SessionListener.Scope

Field Summary

Fields

Modifier and Type	Field and Description
private java.util.Set<java.lang.String>	activeTables Names of active temp tables in the order they were created
private java.util.Map<TemporaryBuffer,java.util.Map<TemporaryBuffer,java.lang.Object>>	domains Map of master buffers to weak hash maps with slave buffer keys
private Cache<FastCopyHelper.FastCopyKey,FastCopyHelper>	fastCopyCache Cache responsible with storing instances of FastCopyHelper.
private boolean	hasMappingTables Flag to indicate that this context database session has the mapping tables for fast-copy created
private java.util.Map<java.lang.Class<?>,java.util.Map<java.lang.Integer,java.lang.Integer>>	inUseMPIDs Map of DMO interfaces to counts of multiplex IDs currently in use
private int	nextMPID Next value to try when assigning a multiplex ID
private org.roaringbitmap.RoaringBitmap	nonEmptyTableFlags Map of flags indicating whether each virtual table is empty
private java.util.Map<java.lang.Class<?>,RefCount>	ooObjectCounter The counter of stored objects for each DMO interface.
private java.util.Map<java.lang.Class<? extends DataModelObject>,java.util.concurrent.atomic.AtomicLong>	openTables Map of open tables to most recent primary key ID generated
private Persistence.Context	pctx Persistence context for transaction management
private java.util.Set<java.lang.Class<? extends DataModelObject>>	pendingDrop Set of DMO interfaces whose corresponding tables will be dropped at the next commit
private Persistence	persistence Persistence service object for temp tables
private java.util.Map<java.lang.String,java.lang.String>	sweepMap Singleton map of a unique key to session ID string

Constructor Summary

Constructors

Constructor and Description
Context() Default constructor.

Method Summary

Modifier and Type	Method and Description
(package private) void	cleanup() Destroy the user's in-DB PK mapping tables.
(package private) void	createTable(java.lang.Class<? extends DataModelObject> dmoIface, java.lang.String table) Create a temp table in the database for the given DMO interface, if it does not already exist.
void	deregisteredSessionListener() Invoked when this session listener is removed from the list of registered session listeners.
private void	doCreateTable(java.lang.Class<? extends DataModelObject> dmoIface) Issue the SQL statement(s) against the backing database necessary to create the backing temp table needed for the given DMO interface, as well as all indexes defined for that table.
private void	doDropTable(java.lang.Class<? extends DataModelObject> dmoIface) Issue the SQL statement(s) against the backing database necessary to drop the backing temp table for the given DMO interface.
(package private) void	dropTable(TempTable tt, java.lang.String table, java.lang.Class<? extends DataModelObject> dmoIface) Remove the given table from the active temp tables in use within the current context, and add it to the pending drop tables.
private void	dropUnusedTables(boolean sessionClosing) Drop all temporary tables which have been created during the current database session, but which are no longer in use.
private FastCopyHelper	getFastCopyHelper(FastCopyHelper.FastCopyContext fastCopyContext) Get an instance of a FastCopyHelper from the cache if it exists, or create a new one if there is no suitable instance in the cache.
private java.lang.String	getImplicitIndexName(java.lang.Class<? extends DataModelObject> dmoIface) Get the implicit index name.
private java.lang.String	getImplicitSqlIndexName(java.lang.Class<? extends DataModelObject> dmoIface) Get the implicit SQL index name.
(package private) java.lang.Integer	getNextMPID(java.util.Map<java.lang.Integer,java.lang.Integer> inUse) Returns a context-local multiplex ID value.
(package private) int	getTableCount() Report the number of temp tables which currently are in use in the current context for the database associated with this buffer.
private java.lang.String	getTableName(java.lang.Class<?> dmoIface) Get the backing temp table name associated with the given DMO interface, primarily for debugging and error reporting purposes.
(package private) void	init() Initialize this object by storing the persistence service object and registering as a session listener.
(package private) java.lang.Long	nextPrimaryKey(java.lang.Class<? extends DataModelObject> dmoIface, java.lang.Integer multiplexID) Returns the next available primary key for the temp table associated with the given DMO interface.
(package private) void	reclaimKey(java.lang.Class<?> dmoIface, java.lang.Integer multiplexID, java.lang.Long id) Deprecated.
boolean	sessionEvent(SessionListener.Event event) This method is invoked by the persistence context when a Hibernate session has just ended a transaction or is about to close.

Methods inherited from class java.lang.Object

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

Field Detail

inUseMPIDs

private final java.util.Map<java.lang.Class<?>,java.util.Map<java.lang.Integer,java.lang.Integer>> inUseMPIDs

Map of DMO interfaces to counts of multiplex IDs currently in use

openTables

private final java.util.Map<java.lang.Class<? extends DataModelObject>,java.util.concurrent.atomic.AtomicLong> openTables

Map of open tables to most recent primary key ID generated

pendingDrop

private final java.util.Set<java.lang.Class<? extends DataModelObject>> pendingDrop

Set of DMO interfaces whose corresponding tables will be dropped at the next commit

activeTables

private final java.util.Set<java.lang.String> activeTables

Names of active temp tables in the order they were created

nonEmptyTableFlags

private final org.roaringbitmap.RoaringBitmap nonEmptyTableFlags

Map of flags indicating whether each virtual table is empty

sweepMap

private final java.util.Map<java.lang.String,java.lang.String> sweepMap

Singleton map of a unique key to session ID string

persistence

private Persistence persistence

Persistence service object for temp tables

pctx

private Persistence.Context pctx

Persistence context for transaction management

domains

private java.util.Map<TemporaryBuffer,java.util.Map<TemporaryBuffer,java.lang.Object>> domains

Map of master buffers to weak hash maps with slave buffer keys

ooObjectCounter

private final java.util.Map<java.lang.Class<?>,RefCount> ooObjectCounter

The counter of stored objects for each DMO interface.

Only the objects that have active destructors are counted.

nextMPID

private int nextMPID

Next value to try when assigning a multiplex ID

fastCopyCache

private final Cache<FastCopyHelper.FastCopyKey,FastCopyHelper> fastCopyCache

Cache responsible with storing instances of FastCopyHelper.

hasMappingTables

private boolean hasMappingTables

Flag to indicate that this context database session has the mapping tables for fast-copy created

Constructor Detail

Context

Context()

Default constructor.

Method Detail

sessionEvent

public boolean sessionEvent(SessionListener.Event event)
                     throws PersistenceException

This method is invoked by the persistence context when a Hibernate session has just ended a transaction or is about to close. Used as a hook to cleanup temp-table and other resources.

Specified by:

sessionEvent in interface SessionListener

Parameters:

event - Session event type.

Returns:

false, indicating that this session listener should remain registered after this method returns.

Throws:

PersistenceException - if any error occurs dropping temp tables from the closing session.

deregisteredSessionListener

public void deregisteredSessionListener()

Invoked when this session listener is removed from the list of registered session listeners.

This implementation does nothing.

Specified by:

deregisteredSessionListener in interface SessionListener

init

void init()

Initialize this object by storing the persistence service object and registering as a session listener. This method is tolerant of being invoked multiple times, but only does its initialization work the first time it is invoked for the current Context instance.

cleanup

void cleanup()

Destroy the user's in-DB PK mapping tables.

getTableCount

int getTableCount()

Report the number of temp tables which currently are in use in the current context for the database associated with this buffer.

Returns:

Number of temp tables associated with persistence.

getNextMPID

java.lang.Integer getNextMPID(java.util.Map<java.lang.Integer,java.lang.Integer> inUse)

Returns a context-local multiplex ID value.

Parameters:

inUse - Map of multiplex IDs currently in use in this context, to reference count of buffers using them.

Returns:

The next available multiplex ID.

createTable

void createTable(java.lang.Class<? extends DataModelObject> dmoIface,
                 java.lang.String table)

Create a temp table in the database for the given DMO interface, if it does not already exist. This will also create all indexes defined for the temp table.

Parameters:

dmoIface - DMO interface for which a backing temp table is needed.

table - Name of temp table to be created.

dropTable

void dropTable(TempTable tt,
               java.lang.String table,
               java.lang.Class<? extends DataModelObject> dmoIface)

Remove the given table from the active temp tables in use within the current context, and add it to the pending drop tables. This method does not actually drop a table, since all table drops are deferred until the database session notifies it needs cleanup. This prevents potential thrashing in the event a class which creates a temporary buffer and then allows it to go out of scope is invoked repeatedly in a loop.

Parameters:

tt - The temp-table resource.

table - Name of temp table to be dropped.

dmoIface - DMO interface.

nextPrimaryKey

java.lang.Long nextPrimaryKey(java.lang.Class<? extends DataModelObject> dmoIface,
                              java.lang.Integer multiplexID)

Returns the next available primary key for the temp table associated with the given DMO interface.

Parameters:

dmoIface - Data model object interface.

multiplexID - The multiplex ID for the temp-table reclaiming this key.

Returns:

The primary key for a new DMO associated with this buffer.

reclaimKey

@Deprecated
void reclaimKey(java.lang.Class<?> dmoIface,
                            java.lang.Integer multiplexID,
                            java.lang.Long id)

Deprecated.

Prepare a single, primary key for reclamation. On the next, full transaction commit, this key will be made available for re-use. Until then, it will be stored in a set of keys which are pending reclamation. This set will be cleared if the current transaction is rolled back.

Parameters:

dmoIface - DMO interface for temporary table records.

multiplexID - The multiplex ID for the temp-table reclaiming this key.

id - Primary key to be recycled.

dropUnusedTables

private void dropUnusedTables(boolean sessionClosing)
                       throws PersistenceException

Drop all temporary tables which have been created during the current database session, but which are no longer in use. This occurs when the session notifies that it needs cleanup.

Parameters:

sessionClosing - true to mark all open tables as unused, so they are dropped; false to only drop tables previously marked as ready to be dropped.

Throws:

PersistenceException - if a database error occurs dropping any table or creating the transaction which contains these actions.

getImplicitSqlIndexName

private java.lang.String getImplicitSqlIndexName(java.lang.Class<? extends DataModelObject> dmoIface)

Get the implicit SQL index name.

Parameters:

dmoIface - DMO interface which represents the temp table.

Returns:

See above.

getImplicitIndexName

private java.lang.String getImplicitIndexName(java.lang.Class<? extends DataModelObject> dmoIface)

Get the implicit index name.

Parameters:

dmoIface - DMO interface which represents the temp table.

Returns:

See above.

doCreateTable

private void doCreateTable(java.lang.Class<? extends DataModelObject> dmoIface)

Issue the SQL statement(s) against the backing database necessary to create the backing temp table needed for the given DMO interface, as well as all indexes defined for that table. Because temp table instances are multiplexed across nested buffer scopes and across multiple buffers which use the same backing DMO type, this method is invoked only the first time a backing table is actually needed for a particular DMO interface type in the current context. Thereafter, this method is not invoked again, unless the backing table has first been dropped.

Parameters:

dmoIface - DMO interface for which a backing temp table is needed.

Throws:

ErrorConditionException - if an error occurs creating the table and silent error mode is disabled.

See Also:

doDropTable(java.lang.Class<? extends com.goldencode.p2j.persist.DataModelObject>)

doDropTable

private void doDropTable(java.lang.Class<? extends DataModelObject> dmoIface)
                  throws PersistenceException

Issue the SQL statement(s) against the backing database necessary to drop the backing temp table for the given DMO interface. Because temp table instances are multiplexed across nested buffer scopes and across multiple buffers which use the same backing DMO type, this method is invoked only when the current database session is being closed, after the last buffer scope referencing the backing table in the current context has been closed.

Parameters:

dmoIface - DMO interface for which the backing temp table should be dropped.

Throws:

PersistenceException - if an error occurs dropping the table and silent error mode is disabled.

See Also:

doCreateTable(java.lang.Class<? extends com.goldencode.p2j.persist.DataModelObject>)

getTableName

private java.lang.String getTableName(java.lang.Class<?> dmoIface)

Get the backing temp table name associated with the given DMO interface, primarily for debugging and error reporting purposes.

Parameters:

dmoIface - DMO interface for which a table name is needed.

Returns:

Name of the temp table associated with the given interface.

getFastCopyHelper

private FastCopyHelper getFastCopyHelper(FastCopyHelper.FastCopyContext fastCopyContext)

Get an instance of a FastCopyHelper from the cache if it exists, or create a new one if there is no suitable instance in the cache.

Parameters:

fastCopyContext - The context for the FastCopyHelper.

Returns:

FastCopyHelper Instance of FastCopyHelper, either retrieved from cache, or just created.