/*
* Distributed as part of c3p0 v.0.9.2-pre1
*
* Copyright (C) 2010 Machinery For Change, Inc.
*
* Author: Steve Waldman <swaldman@mchange.com>
*
* This library is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License version 2.1, as
* published by the Free Software Foundation.
*
* This software 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this software; see the file LICENSE. If not, write to the
* Free Software Foundation, Inc., 59 Temple Place, Suite 330,
* Boston, MA 02111-1307, USA.
*/
package com.mchange.v2.c3p0;
import java.util.*;
import com.mchange.v2.coalesce.*;
import com.mchange.v2.log.*;
import com.mchange.v2.c3p0.cfg.C3P0ConfigUtils;
import com.mchange.v2.c3p0.impl.*;
import java.sql.SQLException;
import com.mchange.v2.c3p0.impl.IdentityTokenized;
import com.mchange.v2.c3p0.subst.C3P0Substitutions;
import com.mchange.v2.sql.SqlUtils;
import com.mchange.v2.util.DoubleWeakHashMap;
import com.mchange.v2.c3p0.management.*;
/*
* The primary purpose of C3P0Registry is to maintain a mapping of "identityTokens"
* to c3p0 DataSources so that if the same DataSource is looked up (and deserialized
* or dereferenced) via JNDI, c3p0 can ensure that the same instance is always returned.
* But there are subtle issues here. If C3P0Registry maintains hard references to
* DataSources, then they can never be garbage collected. But if c3p0 retains only
* weak references, then applications that look up DataSources, then dereference them,
* and then re-look them up again (not a great idea, but not uncommon) might see
* distinct DataSources over multiple lookups.
*
* C3P0 resolves this issue has followed: At first creation or lookup of a PooledDataSource,
* c3p0 creates a hard reference to that DataSource. So long as the DataSource has not
* been close()ed or DataSources.destroy()ed, subsequent lookups will consistently
* return the same DataSource. If the DataSource is never closed, then there is a potential
* memory leak (as well as the potential Thread leak and Connection leak). But if
* the DataSource is close()ed, only weak refernces to the DataSource will be retained.
* A lookup of a DataSource after it has been close()ed within the current VM may
* return the previously close()ed instance, or may return a fresh instance, depending
* on whether the weak reference has been cleared. In other words, the result of
* looking up a DataSource after having close()ed it in the current VM is undefined.
*
* Note that unpooled c3p0 DataSources are always held by weak references, since
* they are never explicitly close()ed. The result of looking up an unpooled DataSource,
* modifying it, dereferencing it, and then relooking up is therefore undefined as well.
*
* These issues are mostly academic. Under normal use scenarios, how c3p0 deals with
* maintaining its registry doesn't much matter. In the past, c3p0 maintained hard
* references to DataSources indefinitely. At least one user ran into side effects
* of the unwanted retention of old DataSources (in a process left to run for months
* at a time, and frequently reconstructing multiple DataSources), so now we take care
* to ensure that when users properly close() and dereference DataSources, they can
* indeed be garbage collected.
*/
public final class C3P0Registry
{
private final static String MC_PARAM = "com.mchange.v2.c3p0.management.ManagementCoordinator";
//MT: thread-safe
final static MLogger logger = MLog.getLogger( C3P0Registry.class );
//MT: protected by class' lock
static boolean banner_printed = false;
//MT: protected by class' lock
static boolean registry_mbean_registered = false;
//MT: thread-safe, immutable
private static CoalesceChecker CC = IdentityTokenizedCoalesceChecker.INSTANCE;
//MT: protected by class' lock
//a weak, unsynchronized coalescer
private static Coalescer idtCoalescer = CoalescerFactory.createCoalescer(CC, true , false);
//MT: protected by class' lock
private static Map tokensToTokenized = new DoubleWeakHashMap();
//MT: protected by class' lock
private static HashSet unclosedPooledDataSources = new HashSet();
//MT: protected by its own lock
private static Map classNamesToConnectionTesters = Collections.synchronizedMap( new HashMap() );
//MT: protected by its own lock
private static Map classNamesToConnectionCustomizers = Collections.synchronizedMap( new HashMap() );
private static ManagementCoordinator mc;
static
{
classNamesToConnectionTesters.put(C3P0Defaults.connectionTesterClassName(), C3P0Defaults.connectionTester());
String userManagementCoordinator = C3P0ConfigUtils.getPropFileConfigProperty(MC_PARAM);
if (userManagementCoordinator != null)
{
try
{
mc = (ManagementCoordinator) Class.forName(userManagementCoordinator).newInstance();
}
catch (Exception e)
{
if (logger.isLoggable(MLevel.WARNING))
logger.log(MLevel.WARNING,
"Could not instantiate user-specified ManagementCoordinator " + userManagementCoordinator +
". Using NullManagementCoordinator (c3p0 JMX management disabled!)",
e );
mc = new NullManagementCoordinator();
}
}
else
{
try
{
Class.forName("java.lang.management.ManagementFactory");
mc = (ManagementCoordinator) Class.forName( "com.mchange.v2.c3p0.management.ActiveManagementCoordinator" ).newInstance();
}
catch (Exception e)
{
if ( logger.isLoggable( MLevel.INFO ) )
logger.log( MLevel.INFO,
"jdk1.5 management interfaces unavailable... JMX support disabled.",
e);
mc = new NullManagementCoordinator();
}
}
}
public static ConnectionTester getConnectionTester( String className )
{
try
{
ConnectionTester out = (ConnectionTester) classNamesToConnectionTesters.get( className );
if (out == null)
{
out = (ConnectionTester) Class.forName( className ).newInstance();
classNamesToConnectionTesters.put( className, out );
}
return out;
}
catch (Exception e)
{
if (logger.isLoggable( MLevel.WARNING ))
logger.log( MLevel.WARNING,
"Could not create for find ConnectionTester with class name '" +
className + "'. Using default.",
e );
return C3P0Defaults.connectionTester();
}
}
public static ConnectionCustomizer getConnectionCustomizer( String className ) throws SQLException
{
if ( className == null )
return null;
else
{
try
{
ConnectionCustomizer out = (ConnectionCustomizer) classNamesToConnectionCustomizers.get( className );
if (out == null)
{
out = (ConnectionCustomizer) Class.forName( className ).newInstance();
classNamesToConnectionCustomizers.put( className, out );
}
return out;
}
catch (Exception e)
{
if (logger.isLoggable( MLevel.WARNING ))
logger.log( MLevel.WARNING,
"Could not create for find ConnectionCustomizer with class name '" +
className + "'.",
e );
throw SqlUtils.toSQLException( e );
}
}
}
// must be called from a static sync'ed method
private static void banner()
{
if (! banner_printed )
{
if (logger.isLoggable( MLevel.INFO ) )
logger.info("Initializing c3p0-" + C3P0Substitutions.VERSION + " [built " + C3P0Substitutions.TIMESTAMP +
"; debug? " + C3P0Substitutions.DEBUG +
"; trace: " + C3P0Substitutions.TRACE
+']');
banner_printed = true;
}
}
// must be called from a static, sync'ed method
private static void attemptRegisterRegistryMBean()
{
if (! registry_mbean_registered)
{
mc.attemptManageC3P0Registry();
registry_mbean_registered = true;
}
}
// must be called with class' lock
private static boolean isIncorporated( IdentityTokenized idt )
{ return tokensToTokenized.keySet().contains( idt.getIdentityToken() ); }
// must be called with class' lock
private static void incorporate( IdentityTokenized idt )
{
tokensToTokenized.put( idt.getIdentityToken(), idt );
if (idt instanceof PooledDataSource)
{
unclosedPooledDataSources.add( idt );
mc.attemptManagePooledDataSource( (PooledDataSource) idt );
}
}
public static synchronized IdentityTokenized reregister(IdentityTokenized idt)
{
if (idt instanceof PooledDataSource)
{
banner();
attemptRegisterRegistryMBean();
}
if (idt.getIdentityToken() == null)
throw new RuntimeException("[c3p0 issue] The identityToken of a registered object should be set prior to registration.");
IdentityTokenized coalesceCheck = (IdentityTokenized) idtCoalescer.coalesce(idt);
if (! isIncorporated( coalesceCheck ))
incorporate( coalesceCheck );
return coalesceCheck;
}
public static synchronized void markClosed(PooledDataSource pds)
{
unclosedPooledDataSources.remove(pds);
mc.attemptUnmanagePooledDataSource( pds );
if (unclosedPooledDataSources.isEmpty())
{
mc.attemptUnmanageC3P0Registry();
registry_mbean_registered = false;
}
}
public synchronized static Set getPooledDataSources()
{ return (Set) unclosedPooledDataSources.clone(); }
public synchronized static Set pooledDataSourcesByName( String dataSourceName )
{
Set out = new HashSet();
for (Iterator ii = unclosedPooledDataSources.iterator(); ii.hasNext(); )
{
PooledDataSource pds = (PooledDataSource) ii.next();
if ( pds.getDataSourceName().equals( dataSourceName ) )
out.add( pds );
}
return out;
}
public synchronized static PooledDataSource pooledDataSourceByName( String dataSourceName )
{
for (Iterator ii = unclosedPooledDataSources.iterator(); ii.hasNext(); )
{
PooledDataSource pds = (PooledDataSource) ii.next();
if ( pds.getDataSourceName().equals( dataSourceName ) )
return pds;
}
return null;
}
public synchronized static Set allIdentityTokens()
{
Set out = Collections.unmodifiableSet( tokensToTokenized.keySet() );
//System.err.println( "allIdentityTokens(): " + out );
return out;
}
public synchronized static Set allIdentityTokenized()
{
HashSet out = new HashSet();
out.addAll( tokensToTokenized.values() );
//System.err.println( "allIdentityTokenized(): " + out );
return Collections.unmodifiableSet( out );
}
public synchronized static Set allPooledDataSources()
{
Set out = Collections.unmodifiableSet( unclosedPooledDataSources );
//System.err.println( "allPooledDataSources(): " + out );
return out;
}
public synchronized static int getNumPooledDataSources()
{ return unclosedPooledDataSources.size(); }
public synchronized static int getNumPoolsAllDataSources() throws SQLException
{
int count = 0;
for (Iterator ii = unclosedPooledDataSources.iterator(); ii.hasNext();)
{
PooledDataSource pds = (PooledDataSource) ii.next();
count += pds.getNumUserPools();
}
return count;
}
public synchronized int getNumThreadsAllThreadPools() throws SQLException
{
int count = 0;
for (Iterator ii = unclosedPooledDataSources.iterator(); ii.hasNext();)
{
PooledDataSource pds = (PooledDataSource) ii.next();
count += pds.getNumHelperThreads();
}
return count;
}
}