DirtyShareFactory.java
/*
** Module : DirtyShareFactory.java
** Abstract : Factory for DirtyShareContext and DirtyShareManager instances
**
** Copyright (c) 2004-2024, Golden Code Development Corporation.
**
** -#- -I- --Date-- -JPRM- ------------------------------------Description------------------------------------
** 001 ECF 20080403 @38630 Created initial version. Factory for DirtyShareContext and
** DirtyShareManager instances.
** 002 SVL 20080806 @39309 Added sessions mapping and functions for deregistration.
** 003 CA 20140513 Added a weight for the context-local var, to ensure predetermined order during
** context reset.
** 004 OM 20200602 New ORM implementation.
** 005 SVL 20130116 Dirty sharing can be disabled in the directory.
** 006 GBB 20230512 Logging methods replaced by CentralLogger/ConversionStatus.
** 007 SVL 20230516 Support for more granular configuration of dirty sharing functionality.
** 008 DDF 20230627 Replaced static variables of DirtyShareSupport with static method calls.
** 009 OM 20240909 Improved Database API.
*/
/*
** This program is free software: you can redistribute it and/or modify
** it under the terms of the GNU Affero General Public License as
** published by the Free Software Foundation, either version 3 of the
** License, or (at your option) any later version.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
** GNU Affero General Public License for more details.
**
** You may find a copy of the GNU Affero GPL version 3 at the following
** location: https://www.gnu.org/licenses/agpl-3.0.en.html
**
** Additional terms under GNU Affero GPL version 3 section 7:
**
** Under Section 7 of the GNU Affero GPL version 3, the following additional
** terms apply to the works covered under the License. These additional terms
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** Affero GPL version 3 and may not be removed by you.
**
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**
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*/
package com.goldencode.p2j.persist.dirty;
import java.util.*;
import com.goldencode.p2j.net.*;
import com.goldencode.p2j.persist.*;
import com.goldencode.p2j.persist.remote.*;
import com.goldencode.p2j.security.*;
import com.goldencode.p2j.util.*;
import com.goldencode.p2j.util.logging.*;
/**
* Factory for {@link DirtyShareContext} and {@link DirtyShareManager} instances. The manager keeps a cache of
* one of these instances for each database and provides the values at request until they are expressly
* unregistered.
*/
public final class DirtyShareFactory
{
/** Cache of {@link DefaultDirtyShareManager} instances by database */
private static final Map<Database, DirtyShareManager> cache = new HashMap<>();
/** Map of DirtyShareManager to Session instances. */
private static final Map<DirtyShareManager, Session> sessions = new HashMap<>();
/** Context local map of Databases to DirtyShareContext instances */
private static final ContextLocal<Map<Database, DirtyShareContext>> local =
new ContextLocal<Map<Database, DirtyShareContext>>()
{
public WeightFactor getWeight()
{
return WeightFactor.LEVEL_7;
}
protected Map<Database, DirtyShareContext> initialValue()
{
return new HashMap<>();
}
protected void cleanup(Map<Database, DirtyShareContext> map)
{
for (DirtyShareContext ctx : map.values())
{
ctx.cleanup();
}
}
};
/**
* Get the dirty share context for the given, primary database. This method will first check a local cache
* for the context. If not present in the cache, the context is created and cached for future retrievals.
* For the temporary table database and when PRIMARY_NON_DIRTY is specified, {@code null} is returned.
*
* @param database
* Primary database which is the key for the dirty share context in the local cache. Use
* {@code PRIMARY_NON_DIRTY} database type to request a NOP context for primary permanent tables
* that are marked as non DIRTY-READ.
*
* @return Dirty share context associated with the given database.
*/
public static DirtyShareContext getContextInstance(Database database)
{
if (!(DirtyShareSupport.isEnabledCrossSession() || DirtyShareSupport.isEnabledIntraSession()) ||
database.getType() == Database.Type.PRIMARY_NON_DIRTY ||
database.isTemporary())
{
return null;
}
Map<Database, DirtyShareContext> map = local.get();
DirtyShareContext ctx = map.get(database);
if (ctx == null)
{
ctx = new DirtyShareContext(getManagerInstance(database));
map.put(database, ctx);
}
return ctx;
}
/**
* Removes the dirty share share context for the given database from the local cache, if any.
*
* @param database
* Primary database which is the key for the dirty share context in the local cache.
*/
public static void unregisterContextInstance(Database database)
{
Map<Database, DirtyShareContext> map = local.get();
if (map.remove(database) == null)
{
CentralLogger.get(DirtyShareFactory.class)
.info(database + " could not be unregistered from " + "DirtyShareFactory");
}
}
/**
* Get the dirty share manager for the given, primary database. This method will first check a shared cache
* for the manager. If not present in the cache, the manager is created and cached for future retrievals.
* For local databases, an instance of {@link DefaultDirtyShareManager} is returned. For remote databases,
* an instance of {@link com.goldencode.p2j.persist.remote.RemoteDirtyShareManager} is returned.
*
* @param database
* Primary database which is the key for the dirty share manager in the shared cache. Use
* {@code PRIMARY_NON_DIRTY} database type to request a NOP context for primary permanent tables
* that are marked as non DIRTY-READ.
*
* @return Dirty share manager associated with the given database.
*/
public static DirtyShareManager getManagerInstance(Database database)
{
if (database.isTemporary() || database.getType() == Database.Type.PRIMARY_NON_DIRTY)
{
throw new IllegalArgumentException(
"Cannot create DirtyShareManager for temporary or non-dirty table database)");
}
synchronized (cache)
{
DirtyShareManager dsm = cache.get(database);
if (dsm == null)
{
if (database.isLocal())
{
dsm = new DefaultDirtyShareManager(database);
}
else
{
// retrieve network session
Session session = ConnectionManager.getSession(database);
// get dirty share manager multiplexer proxy
DirtyShareMultiplexer multiplexer = (DirtyShareMultiplexer)
RemoteObject.obtainNetworkInstance(DirtyShareMultiplexer.class, session);
// Instantiate the remote dirty share manager.
RemoteDirtyShareManager rdsm = new RemoteDirtyShareManager(multiplexer);
rdsm.setDatabase(database);
dsm = rdsm;
sessions.put(dsm, session);
}
cache.put(database, dsm);
}
return dsm;
}
}
/**
* Determines whether the given session for the given database is used by the dirty share manager for this
* database.
*
* @param database
* Primary database which is the key for the dirty share manager in the shared cache.
* @param session
* Candidate for checking whether it is used by the shared manager.
*
* @return {@code true} of the session is used by the dirty share manager for this database, {@code false}
* otherwise.
*/
public static boolean isUsedByManager(Database database, Session session)
{
synchronized (cache)
{
DirtyShareManager dsm = cache.get(database);
return dsm != null && session == sessions.get(dsm);
}
}
/**
* Removes the dirty share manager for the given database from the shared cache, if any. Also terminates
* and removes from the cache session used by this manager.
*
* @param database
* Primary database which is the key for the dirty share manager in the shared cache.
*/
public static void unregisterManagerForDatabase(Database database)
{
Session session = null;
synchronized (cache)
{
DirtyShareManager dsm = cache.get(database);
if (dsm != null)
{
cache.remove(database);
session = sessions.remove(dsm);
}
}
if (session != null)
{
session.terminate();
}
}
}