/*
* 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.stmt;
import java.util.*;
import java.sql.*;
import java.lang.reflect.*;
import com.mchange.v2.async.AsynchronousRunner;
import com.mchange.v2.holders.SynchronizedIntHolder;
import com.mchange.v2.sql.SqlUtils;
import com.mchange.v2.util.ResourceClosedException;
import com.mchange.v2.log.*;
import com.mchange.v1.db.sql.StatementUtils;
import java.io.StringWriter;
import java.io.PrintWriter;
import java.io.IOException;
import com.mchange.v2.io.IndentedWriter;
public abstract class GooGooStatementCache
{
private final static MLogger logger = MLog.getLogger( GooGooStatementCache.class );
private final static int DESTROY_NEVER = 0;
private final static int DESTROY_IF_CHECKED_IN = 1 << 0;
private final static int DESTROY_IF_CHECKED_OUT = 1 << 1;
private final static int DESTROY_ALWAYS = (DESTROY_IF_CHECKED_IN | DESTROY_IF_CHECKED_OUT);
// Alternative culling algorithm minimizes hazard to drivers that can't have Statements closed beneath
// active Connections. No longer necessary now that we've implemented deferred culling and not so good
// since when all Connections are in use, nothing can be culled and new Statements cannot be cached
private final static boolean CULL_ONLY_FROM_UNUSED_CONNECTIONS = false; //alternative culling
/* MT: protected by this's lock */
// contains all statements in the cache,
// organized by connection
ConnectionStatementManager cxnStmtMgr;
// contains all statements in the cache,
// bound to the keys that produced them
HashMap stmtToKey = new HashMap();
// maps all known keys to their set of statements
// and to a queue of statements, if any, available
// for checkout
HashMap keyToKeyRec = new HashMap();
// contains all checked out statements -- in the cache,
// but not currently available for checkout, nor for
// culling in case of overflow
HashSet checkedOut = new HashSet();
/* MT: end protected by this' lock */
/* MT: protected by its own lock */
AsynchronousRunner blockingTaskAsyncRunner;
// This set is used to ensure that multiple threads
// do not try to remove the same statement from the
// cache, if for example a Statement is both deathmarched
// away and its parent Connection is closed.
//
// ALL ACCESS SHOULD BE EXPLICITLY SYNCHRONIZED
// ON removalPending's lock!
HashSet removalPending = new HashSet();
StatementDestructionManager destructo;
/* MT: end protected by its own lock */
public GooGooStatementCache(AsynchronousRunner blockingTaskAsyncRunner, AsynchronousRunner deferredStatementDestroyer)
{
this.blockingTaskAsyncRunner = blockingTaskAsyncRunner;
this.cxnStmtMgr = createConnectionStatementManager();
this.destructo =
deferredStatementDestroyer != null ?
(StatementDestructionManager) new CautiousStatementDestructionManager( deferredStatementDestroyer ) :
(StatementDestructionManager) new IncautiousStatementDestructionManager( blockingTaskAsyncRunner );
}
public synchronized int getNumStatements()
{ return this.isClosed() ? -1 : countCachedStatements(); }
public synchronized int getNumStatementsCheckedOut()
{ return this.isClosed() ? -1 : checkedOut.size(); }
public synchronized int getNumConnectionsWithCachedStatements()
{ return isClosed() ? -1 : cxnStmtMgr.getNumConnectionsWithCachedStatements(); }
public synchronized String dumpStatementCacheStatus()
{
if (isClosed())
return this + "status: Closed.";
else
{
StringWriter sw = new StringWriter(2048);
IndentedWriter iw = new IndentedWriter( sw );
try
{
iw.print(this);
iw.println(" status:");
iw.upIndent();
iw.println("core stats:");
iw.upIndent();
iw.print("num cached statements: ");
iw.println( this.countCachedStatements() );
iw.print("num cached statements in use: ");
iw.println( checkedOut.size() );
iw.print("num connections with cached statements: ");
iw.println(cxnStmtMgr.getNumConnectionsWithCachedStatements());
iw.downIndent();
iw.println("cached statement dump:");
iw.upIndent();
for (Iterator ii = cxnStmtMgr.connectionSet().iterator(); ii.hasNext();)
{
Connection pcon = (Connection) ii.next();
iw.print(pcon);
iw.println(':');
iw.upIndent();
for (Iterator jj = cxnStmtMgr.statementSet(pcon).iterator(); jj.hasNext();)
iw.println(jj.next());
iw.downIndent();
}
iw.downIndent();
iw.downIndent();
return sw.toString();
}
catch (IOException e)
{
if (logger.isLoggable(MLevel.SEVERE))
logger.log(MLevel.SEVERE, "Huh? We've seen an IOException writing to s StringWriter?!", e);
return e.toString();
}
}
}
public void waitMarkConnectionInUse(Connection physicalConnection) throws InterruptedException { destructo.waitMarkConnectionInUse( physicalConnection ); }
public boolean tryMarkConnectionInUse(Connection physicalConnection) { return destructo.tryMarkConnectionInUse( physicalConnection ); }
public void unmarkConnectionInUse(Connection physicalConnection) { destructo.unmarkConnectionInUse( physicalConnection ); }
public Boolean inUse(Connection physicalConnection) { return destructo.tvlInUse( physicalConnection ); }
public int getStatementDestroyerNumConnectionsInUse() { return destructo.getNumConnectionsInUse(); }
public int getStatementDestroyerNumConnectionsWithDeferredDestroyStatements() { return destructo.getNumConnectionsWithDeferredDestroyStatements(); }
public int getStatementDestroyerNumDeferredDestroyStatements() { return destructo.getNumDeferredDestroyStatements(); }
abstract ConnectionStatementManager createConnectionStatementManager();
public synchronized Object checkoutStatement( Connection physicalConnection,
Method stmtProducingMethod,
Object[] args )
throws SQLException, ResourceClosedException
{
try
{
Object out = null;
StatementCacheKey key = StatementCacheKey.find( physicalConnection,
stmtProducingMethod,
args );
LinkedList l = checkoutQueue( key );
if (l == null || l.isEmpty()) //we need a new statement
{
// we might wait() here...
// don't presume atomicity before and after!
out = acquireStatement( physicalConnection, stmtProducingMethod, args );
if ( prepareAssimilateNewStatement( physicalConnection ) )
assimilateNewCheckedOutStatement( key, physicalConnection, out );
// else case: we can't assimilate the statement...
// so, we just return our newly created statement, without caching it.
// on check-in, it will simply be destroyed... this is an "overload statement"
}
else //okay, we can use an old one
{
if (Debug.DEBUG && Debug.TRACE == Debug.TRACE_MAX)
logger.finest(this.getClass().getName() + " ----> CACHE HIT");
//System.err.println("-------------> CACHE HIT!");
out = l.get(0);
l.remove(0);
if (! checkedOut.add( out ))
throw new RuntimeException("Internal inconsistency: " +
"Checking out a statement marked " +
"as already checked out!");
removeStatementFromDeathmarches( out, physicalConnection );
}
if (Debug.DEBUG && Debug.TRACE == Debug.TRACE_MAX)
{
//System.err.print("checkoutStatement(): ");
//printStats();
if (logger.isLoggable(MLevel.FINEST))
logger.finest("checkoutStatement: " + statsString());
}
return out;
}
catch (NullPointerException npe)
{
if (checkedOut == null) //we're closed
{
if (logger.isLoggable(MLevel.FINE))
logger.log( MLevel.FINE,
"A client attempted to work with a closed Statement cache, " + "" +
"provoking a NullPointerException. c3p0 recovers, but this should be rare.",
npe);
throw new ResourceClosedException( npe );
}
else
throw npe;
}
}
public synchronized void checkinStatement( Object pstmt )
throws SQLException
{
if (checkedOut == null) //we're closed
{
destructo.synchronousDestroyStatement( pstmt );
return;
}
else if (! checkedOut.remove( pstmt ) )
{
if (! ourResource( pstmt ) ) //this is not our resource, or it is an overload statement
destructo.uncheckedDestroyStatement( pstmt ); // so we just destroy
//in the else case, it's already checked-in, so we ignore
return;
}
try
{ refreshStatement( (PreparedStatement) pstmt ); }
catch (Exception e)
{
if (Debug.DEBUG)
{
// System.err.println("Problem with checked-in Statement, discarding.");
// e.printStackTrace();
if (logger.isLoggable(MLevel.INFO))
logger.log(MLevel.INFO, "Problem with checked-in Statement, discarding.", e);
}
// swaldman -- 2004-01-31: readd problem statement to checkedOut for consistency
// the statement is not yet checked-in, but it is removed from checked out, and this
// violates the consistency assumption of removeStatement(). Thanks to Zach Scott for
// calling attention to this issue.
checkedOut.add( pstmt );
removeStatement( pstmt, DESTROY_ALWAYS ); //force destruction of the statement even though it appears checked-out
return;
}
StatementCacheKey key = (StatementCacheKey) stmtToKey.get( pstmt );
if (Debug.DEBUG && key == null)
throw new RuntimeException("Internal inconsistency: " +
"A checked-out statement has no key associated with it!");
LinkedList l = checkoutQueue( key );
l.add( pstmt );
addStatementToDeathmarches( pstmt, key.physicalConnection );
if (Debug.DEBUG && Debug.TRACE == Debug.TRACE_MAX)
{
// System.err.print("checkinStatement(): ");
// printStats();
if (logger.isLoggable(MLevel.FINEST))
logger.finest("checkinStatement(): " + statsString());
}
}
public synchronized void checkinAll(Connection pcon)
throws SQLException
{
//new Exception("checkinAll()").printStackTrace();
Set stmtSet = cxnStmtMgr.statementSet( pcon );
if (stmtSet != null)
{
for (Iterator ii = stmtSet.iterator(); ii.hasNext(); )
{
Object stmt = ii.next();
if (checkedOut.contains( stmt ))
checkinStatement( stmt );
}
}
if (Debug.DEBUG && Debug.TRACE == Debug.TRACE_MAX)
{
// System.err.print("checkinAll(): ");
// printStats();
if (logger.isLoggable(MLevel.FINEST))
logger.log(MLevel.FINEST, "checkinAll(): " + statsString());
}
}
/*
* we only selectively sync' parts of this method, because we wish to wait for
* Statements we wish to destroy the Statements synchronously, but without
* holding the pool's lock.
*/
public void closeAll(Connection pcon) throws SQLException
{
// System.err.println( this + ": closeAll( " + pcon + " )" );
// new Exception("closeAll()").printStackTrace();
// assert !Thread.holdsLock( this );
if (! this.isClosed())
{
if (Debug.DEBUG && Debug.TRACE == Debug.TRACE_MAX)
{
if (logger.isLoggable(MLevel.FINEST))
{
logger.log(MLevel.FINEST, "ENTER METHOD: closeAll( " + pcon + " )! -- num_connections: " +
cxnStmtMgr.getNumConnectionsWithCachedStatements());
//logger.log(MLevel.FINEST, "Set of statements for connection: " + cSet + (cSet != null ? "; size: " + cSet.size() : ""));
}
}
Set stmtSet = null;
synchronized (this)
{
Set cSet = cxnStmtMgr.statementSet( pcon );
if (cSet != null)
{
//the removeStatement(...) removes from cSet, so we can't be iterating over cSet directly
stmtSet = new HashSet( cSet );
//System.err.println("SIZE FOR CONNECTION SET: " + stmtSet.size());
for (Iterator ii = stmtSet.iterator(); ii.hasNext(); )
{
Object stmt = ii.next();
// we remove without destroying, leaving the destruction
// until when we lose the pool's lock
removeStatement( stmt, DESTROY_NEVER );
}
}
}
if ( stmtSet != null )
{
for (Iterator ii = stmtSet.iterator(); ii.hasNext(); )
{
Object stmt = ii.next();
destructo.synchronousDestroyStatement( stmt );
}
}
if (Debug.DEBUG && Debug.TRACE == Debug.TRACE_MAX)
{
if (logger.isLoggable(MLevel.FINEST))
logger.finest("closeAll(): " + statsString());
}
}
// else
// {
// if (logger.isLoggable(MLevel.FINER))
// logger.log(MLevel.FINER,
// this + ": call to closeAll() when statment cache is already closed! [not harmful! debug only!]",
// new Exception("DUPLICATE CLOSE DEBUG STACK TRACE."));
// }
}
public synchronized void close()
throws SQLException
{
//System.err.println( this + ": close()" );
if (! isClosed())
{
for (Iterator ii = stmtToKey.keySet().iterator(); ii.hasNext(); )
destructo.synchronousDestroyStatement( ii.next() );
destructo.close();
cxnStmtMgr = null;
stmtToKey = null;
keyToKeyRec = null;
checkedOut = null;
}
else
{
if (logger.isLoggable(MLevel.FINE))
logger.log(MLevel.FINE, this + ": duplicate call to close() [not harmful! -- debug only!]", new Exception("DUPLICATE CLOSE DEBUG STACK TRACE."));
}
}
public synchronized boolean isClosed()
{ return cxnStmtMgr == null; }
/* non-public methods that MUST be called with this' lock */
abstract boolean prepareAssimilateNewStatement(Connection pcon);
abstract void addStatementToDeathmarches( Object pstmt, Connection physicalConnection );
abstract void removeStatementFromDeathmarches( Object pstmt, Connection physicalConnection );
final int countCachedStatements()
{ return stmtToKey.size(); }
private void assimilateNewCheckedOutStatement( StatementCacheKey key,
Connection pConn,
Object ps )
{
stmtToKey.put( ps, key );
HashSet ks = keySet( key );
if (ks == null)
keyToKeyRec.put( key, new KeyRec() );
else
{
//System.err.println("-------> Multiply prepared statement! " + key.stmtText );
if (logger.isLoggable(MLevel.INFO))
logger.info("Multiply prepared statement! " + key.stmtText );
if (Debug.DEBUG && logger.isLoggable(MLevel.FINE))
logger.fine("(The same statement has already been prepared by this Connection, " +
"and that other instance has not yet been closed, so the statement pool " +
"has to prepare a second PreparedStatement object rather than reusing " +
"the previously-cached Statement. The new Statement will be cached, in case " +
"you frequently need multiple copies of this Statement.)");
}
keySet( key ).add( ps );
cxnStmtMgr.addStatementForConnection( ps, pConn );
if (Debug.DEBUG && Debug.TRACE == Debug.TRACE_MAX)
{
// System.err.println("cxnStmtMgr.statementSet( " + pConn + " ).size(): " +
// cxnStmtMgr.statementSet( pConn ).size());
if (logger.isLoggable(MLevel.FINEST))
logger.finest("cxnStmtMgr.statementSet( " + pConn + " ).size(): " +
cxnStmtMgr.statementSet( pConn ).size());
}
checkedOut.add( ps );
}
private void removeStatement( Object ps , int destruction_policy )
{
synchronized (removalPending)
{
if ( removalPending.contains( ps ) )
return;
else
removalPending.add(ps);
}
StatementCacheKey sck = (StatementCacheKey) stmtToKey.remove( ps );
removeFromKeySet( sck, ps );
Connection pConn = sck.physicalConnection;
boolean checked_in = !checkedOut.contains( ps );
if ( checked_in )
{
removeStatementFromDeathmarches( ps, pConn );
removeFromCheckoutQueue( sck , ps );
if ((destruction_policy & DESTROY_IF_CHECKED_IN) != 0)
destructo.deferredDestroyStatement( pConn, ps );
}
else
{
checkedOut.remove( ps );
if ((destruction_policy & DESTROY_IF_CHECKED_OUT) != 0)
destructo.deferredDestroyStatement( pConn, ps );
}
boolean check = cxnStmtMgr.removeStatementForConnection( ps, pConn );
if (Debug.DEBUG && check == false)
{
//new Exception("WARNING: removed a statement that apparently wasn't in a statement set!!!").printStackTrace();
if (logger.isLoggable(MLevel.WARNING))
logger.log(MLevel.WARNING,
this + " removed a statement that apparently wasn't in a statement set!!!",
new Exception("LOG STACK TRACE"));
}
synchronized (removalPending)
{ removalPending.remove(ps); }
}
private Object acquireStatement(final Connection pConn,
final Method stmtProducingMethod,
final Object[] args )
throws SQLException
{
try
{
final Object[] outHolder = new Object[1];
final SQLException[] exceptionHolder = new SQLException[1];
class StmtAcquireTask implements Runnable
{
public void run()
{
try
{
outHolder[0] =
stmtProducingMethod.invoke( pConn,
args );
}
catch ( InvocationTargetException e )
{
Throwable targetException = e.getTargetException();
if ( targetException instanceof SQLException )
exceptionHolder[0] = (SQLException) targetException;
else
exceptionHolder[0]
= SqlUtils.toSQLException(targetException);
}
catch ( Exception e )
{ exceptionHolder[0] = SqlUtils.toSQLException(e); }
finally
{
synchronized ( GooGooStatementCache.this )
{ GooGooStatementCache.this.notifyAll(); }
}
}
}
Runnable r = new StmtAcquireTask();
blockingTaskAsyncRunner.postRunnable(r);
while ( outHolder[0] == null && exceptionHolder[0] == null )
this.wait(); //give up our lock while the Statement gets prepared
if (exceptionHolder[0] != null)
throw exceptionHolder[0];
else
{
Object out = outHolder[0];
return out;
}
}
catch ( InterruptedException e )
{ throw SqlUtils.toSQLException( e ); }
}
private KeyRec keyRec( StatementCacheKey key )
{ return ((KeyRec) keyToKeyRec.get( key )); }
private HashSet keySet( StatementCacheKey key )
{
KeyRec rec = keyRec( key );
return (rec == null ? null : rec.allStmts);
}
private boolean removeFromKeySet( StatementCacheKey key, Object pstmt )
{
boolean out;
HashSet stmtSet = keySet( key );
out = stmtSet.remove( pstmt );
if (stmtSet.isEmpty() && checkoutQueue( key ).isEmpty())
keyToKeyRec.remove( key );
return out;
}
private LinkedList checkoutQueue( StatementCacheKey key )
{
KeyRec rec = keyRec( key );
return ( rec == null ? null : rec.checkoutQueue );
}
private boolean removeFromCheckoutQueue( StatementCacheKey key, Object pstmt )
{
boolean out;
LinkedList q = checkoutQueue( key );
out = q.remove( pstmt );
if (q.isEmpty() && keySet( key ).isEmpty())
keyToKeyRec.remove( key );
return out;
}
private boolean ourResource( Object ps )
{ return stmtToKey.keySet().contains( ps ); }
private void refreshStatement( PreparedStatement ps ) throws Exception
{ ps.clearParameters(); }
private void printStats()
{
//new Exception("printStats()").printStackTrace();
int total_size = this.countCachedStatements();
int checked_out_size = checkedOut.size();
int num_connections = cxnStmtMgr.getNumConnectionsWithCachedStatements();
int num_keys = keyToKeyRec.size();
System.err.print(this.getClass().getName() + " stats -- ");
System.err.print("total size: " + total_size);
System.err.print("; checked out: " + checked_out_size);
System.err.print("; num connections: " + num_connections);
System.err.println("; num keys: " + num_keys);
}
private String statsString()
{
int total_size = this.countCachedStatements();
int checked_out_size = checkedOut.size();
int num_connections = cxnStmtMgr.getNumConnectionsWithCachedStatements();
int num_keys = keyToKeyRec.size();
StringBuffer sb = new StringBuffer(255);
sb.append(this.getClass().getName());
sb.append(" stats -- ");
sb.append("total size: ");
sb.append(total_size);
sb.append("; checked out: ");
sb.append(checked_out_size);
sb.append("; num connections: ");
sb.append(num_connections);
int in_use = destructo.countConnectionsInUse();
if (in_use >= 0)
{
sb.append("; num connections in use: ");
sb.append(in_use);
}
sb.append("; num keys: ");
sb.append(num_keys);
return sb.toString();
}
private static class KeyRec
{
HashSet allStmts = new HashSet();
LinkedList checkoutQueue = new LinkedList();
}
protected class Deathmarch
{
TreeMap longsToStmts = new TreeMap();
HashMap stmtsToLongs = new HashMap();
long last_long = -1;
public void deathmarchStatement( Object ps )
{
assert Thread.holdsLock(GooGooStatementCache.this);
//System.err.println("deathmarchStatement( " + ps + " )");
if (Debug.DEBUG)
{
Long old = (Long) stmtsToLongs.get( ps );
if (old != null)
throw new RuntimeException("Internal inconsistency: " +
"A statement is being double-deathmatched. no checked-out statements should be in a deathmarch already; " +
"no already checked-in statement should be deathmarched!");
}
Long youth = getNextLong();
stmtsToLongs.put( ps, youth );
longsToStmts.put( youth, ps );
}
public void undeathmarchStatement( Object ps )
{
assert Thread.holdsLock(GooGooStatementCache.this);
Long old = (Long) stmtsToLongs.remove( ps );
if (Debug.DEBUG && old == null)
throw new RuntimeException("Internal inconsistency: " +
"A (not new) checking-out statement is not in deathmarch.");
Object check = longsToStmts.remove( old );
if (Debug.DEBUG && old == null)
throw new RuntimeException("Internal inconsistency: " +
"A (not new) checking-out statement is not in deathmarch.");
}
public boolean cullNext()
{
assert Thread.holdsLock(GooGooStatementCache.this);
Object cullMeStmt = null;
StatementCacheKey sck = null;
if (CULL_ONLY_FROM_UNUSED_CONNECTIONS) //alternative implementation -- cull only from unused Connections
{
for (Iterator ii = longsToStmts.keySet().iterator(); cullMeStmt == null && ii.hasNext(); )
{
Long l = (Long) ii.next();
Object maybeCullMe = longsToStmts.get( l );
StatementCacheKey maybeSck = (StatementCacheKey) stmtToKey.get( maybeCullMe );
Connection pCon = maybeSck.physicalConnection;
if (! destructo.knownInUse( pCon ) ) //we don't cull Statements underneath of Connections in current use
{
// we've found the first statement in the deathmarch
// that we can cull...
cullMeStmt = maybeCullMe;
sck = maybeSck;
}
}
}
else //strict LRU culling
{
if ( !longsToStmts.isEmpty() )
{
Long l = (Long) longsToStmts.firstKey();
cullMeStmt = longsToStmts.get( l );
}
}
if ( cullMeStmt == null ) // we didn't find a Statement we could cull
return false;
else
{
if (Debug.DEBUG && Debug.TRACE == Debug.TRACE_MAX)
{
if (sck == null)
sck = ((StatementCacheKey) stmtToKey.get(cullMeStmt));
if (logger.isLoggable(MLevel.FINEST))
logger.finest("CULLING: " + sck.stmtText);
}
// we do not undeathmarch the statement ourselves, because removeStatement( ... )
// should remove from all deathmarches...
removeStatement( cullMeStmt, DESTROY_ALWAYS );
if (Debug.DEBUG && this.contains( cullMeStmt ))
throw new RuntimeException("Inconsistency!!! Statement culled from deathmarch failed to be removed by removeStatement( ... )!");
return true;
}
}
/*
public boolean cullNext()
{
if ( longsToStmts.isEmpty() )
return false;
else
{
Long l = (Long) longsToStmts.firstKey();
Object ps = longsToStmts.get( l );
if (Debug.DEBUG && Debug.TRACE == Debug.TRACE_MAX)
{
// System.err.println("CULLING: " +
// ((StatementCacheKey) stmtToKey.get(ps)).stmtText);
if (logger.isLoggable(MLevel.FINEST))
logger.finest("CULLING: " + ((StatementCacheKey) stmtToKey.get(ps)).stmtText);
}
// we do not undeathmarch the statement ourselves, because removeStatement( ... )
// should remove from all deathmarches...
removeStatement( ps, DESTROY_ALWAYS );
if (Debug.DEBUG && this.contains( ps ))
throw new RuntimeException("Inconsistency!!! Statement culled from deathmarch failed to be removed by removeStatement( ... )!");
return true;
}
}
*/
public boolean contains( Object ps )
{ return stmtsToLongs.keySet().contains( ps ); }
public int size()
{ return longsToStmts.size(); }
private Long getNextLong()
{ return new Long( ++last_long ); }
}
protected static abstract class ConnectionStatementManager
{
Map cxnToStmtSets = new HashMap();
public int getNumConnectionsWithCachedStatements()
{ return cxnToStmtSets.size(); }
public Set connectionSet()
{ return cxnToStmtSets.keySet(); }
public Set statementSet( Connection pcon )
{ return (Set) cxnToStmtSets.get( pcon ); }
public int getNumStatementsForConnection( Connection pcon )
{
Set stmtSet = statementSet( pcon );
return (stmtSet == null ? 0 : stmtSet.size());
}
public void addStatementForConnection( Object ps, Connection pcon )
{
Set stmtSet = statementSet( pcon );
if (stmtSet == null)
{
stmtSet = new HashSet();
cxnToStmtSets.put( pcon, stmtSet );
}
stmtSet.add( ps );
}
public boolean removeStatementForConnection( Object ps, Connection pcon )
{
boolean out;
Set stmtSet = statementSet( pcon );
if ( stmtSet != null )
{
out = stmtSet.remove( ps );
if (stmtSet.isEmpty())
cxnToStmtSets.remove( pcon );
}
else
out = false;
return out;
}
}
// i want this as optimized as possible, so i'm adopting the philosophy that all
// classes are abstract or final, to help enable compiler inlining...
protected static final class SimpleConnectionStatementManager extends ConnectionStatementManager
{}
protected final class DeathmarchConnectionStatementManager extends ConnectionStatementManager
{
Map cxnsToDms = new HashMap();
public void addStatementForConnection( Object ps, Connection pcon )
{
super.addStatementForConnection( ps, pcon );
Deathmarch dm = (Deathmarch) cxnsToDms.get( pcon );
if (dm == null)
{
dm = new Deathmarch();
cxnsToDms.put( pcon, dm );
}
}
public boolean removeStatementForConnection( Object ps, Connection pcon )
{
boolean out = super.removeStatementForConnection( ps, pcon );
if (out)
{
if ( statementSet( pcon ) == null )
cxnsToDms.remove( pcon );
}
return out;
}
public Deathmarch getDeathmarch( Connection pcon )
{ return (Deathmarch) cxnsToDms.get( pcon ); }
}
/*
* Some drivers cannot abide the close()ing of a Statement while the parent Connection object is
* in use elsewhere. For those driver, CautiosStatementDestructionManager should be used. For
* drivers that do not have this issue [formally close()ing a Statement while a Connection is in
* use should be within spec], best to default to the faster, simpler IncautiousStatementDestructionManager
*/
private abstract class StatementDestructionManager
{
AsynchronousRunner runner;
//{ System.err.println("Statement cache destruction manager: " + this.getClass().getName()); }
StatementDestructionManager(AsynchronousRunner runner)
{ this.runner = runner; }
abstract void waitMarkConnectionInUse(Connection physicalConnection) throws InterruptedException;
abstract boolean tryMarkConnectionInUse(Connection physicalConnection);
abstract void unmarkConnectionInUse(Connection physicalConnection);
abstract void deferredDestroyStatement(Object parentConnection, Object pstmt);
// return -1 if unknown
abstract int countConnectionsInUse();
//we don't cull Statements underneat of Connections in current use
abstract boolean knownInUse(Connection pCon);
// to enable assertions about a Connection's status
// returns null if unknown.
//
// "three-valued logic in use"
abstract Boolean tvlInUse( Connection pCon );
abstract int getNumConnectionsInUse();
abstract int getNumConnectionsWithDeferredDestroyStatements();
abstract int getNumDeferredDestroyStatements();
abstract void close();
/* non-public methods that needn't be called with any lock below */
final void uncheckedDestroyStatement( final Object pstmt )
{
class UncheckedStatementCloseTask implements Runnable
{
public void run()
{ StatementUtils.attemptClose( (PreparedStatement) pstmt ); }
}
Runnable r = new UncheckedStatementCloseTask();
runner.postRunnable(r);
}
final void synchronousDestroyStatement( final Object pstmt )
{ StatementUtils.attemptClose( (PreparedStatement) pstmt ); }
/* end non-public methods that needn't be called with any lock */
}
private final class IncautiousStatementDestructionManager extends StatementDestructionManager
{
IncautiousStatementDestructionManager(AsynchronousRunner runner)
{ super( runner ); }
void waitMarkConnectionInUse(Connection physicalConnection) throws InterruptedException {}
boolean tryMarkConnectionInUse(Connection physicalConnection) { return true; }
void unmarkConnectionInUse(Connection physicalConnection) {}
void deferredDestroyStatement(Object parentConnection, Object pstmt) { uncheckedDestroyStatement( pstmt ); }
void close() {}
// return -1 if unknown
int countConnectionsInUse() { return -1; }
// under alternative implementation we don't cull Statements
// underneath of Connections in current use
boolean knownInUse(Connection pCon) { return false; }
Boolean tvlInUse( Connection pCon ) { return null; }
int getNumConnectionsInUse() { return -1; }
int getNumConnectionsWithDeferredDestroyStatements() { return -1; }
int getNumDeferredDestroyStatements() { return -1; }
}
private final class CautiousStatementDestructionManager extends StatementDestructionManager
{
// we refuse to cull PreparedStatements from currently in-use Connections
// to avoid potential concurrency issues in drivers not robust to concurrent
// use of children of a single Connection.
HashSet inUseConnections = new HashSet();
// This Map is used to keep track of Statements removed
// from the cache and "closed", but not actually, physically
// close()ed yet, because when they were removed from the cache,
// their parent Connection was in-use. Under some JDBC drivers,
// (Oracle, this means you), trying to close() a Statement whose
// parent Connection is concurrently in use leads to problems.
// So, we just remove these Statements from the cache, and shove
// them into a "TO BE DESTROYED" list. Only when the parent
// Connection is no longer in use do we actually destroy the removed
// Statements.
HashMap connectionsToZombieStatementSets = new HashMap();
AsynchronousRunner deferredStatementDestroyer;
boolean closed = false;
synchronized void close()
{ closed = true; }
CautiousStatementDestructionManager(AsynchronousRunner deferredStatementDestroyer)
{
super( deferredStatementDestroyer );
this.deferredStatementDestroyer = deferredStatementDestroyer;
}
private String trace()
{
Set keys = connectionsToZombieStatementSets.keySet();
int sum = 0;
for ( Iterator ii = keys.iterator(); ii.hasNext(); )
{
Object con = ii.next();
Set stmts = (Set) connectionsToZombieStatementSets.get( con );
synchronized ( stmts )
{ sum += (stmts == null ? 0 : stmts.size()); }
}
return this.getClass().getName() + " [connections in use: " + inUseConnections.size() + "; connections with deferred statements: " + keys.size() + "; statements to destroy: " + sum + "]";
}
private void printAllStats()
{
printStats();
System.err.println(trace());
}
synchronized void waitMarkConnectionInUse(Connection physicalConnection) throws InterruptedException
{
if (! closed)
{
Set stmts = statementsUnderDestruction( physicalConnection );
if (stmts != null)
{
if (Debug.DEBUG && logger.isLoggable(MLevel.FINE))
{
//System.err.println("*********************************************** => " + stmts);
logger.log(MLevel.FINE,
"A connection is waiting to be accepted by the Statement cache because " +
stmts.size() +
" cached Statements are still being destroyed.");
//printAllStats();
}
while (! stmts.isEmpty())
this.wait();
}
inUseConnections.add( physicalConnection );
}
}
synchronized boolean tryMarkConnectionInUse(Connection physicalConnection)
{
if (! closed)
{
Set stmts = statementsUnderDestruction( physicalConnection );
if ( stmts != null)
{
int sz = stmts.size();
if (Debug.DEBUG && logger.isLoggable(MLevel.FINE))
{
logger.log(MLevel.FINE,
"A connection could not be accepted by the Statement cache because " +
sz +
" cached Statements are still being destroyed.");
}
return false;
}
else
{
inUseConnections.add( physicalConnection );
return true;
}
}
else
return true;
}
synchronized void unmarkConnectionInUse(Connection physicalConnection)
{
boolean unmarked = inUseConnections.remove( physicalConnection );
Set zombieStatements = (Set) connectionsToZombieStatementSets.get( physicalConnection );
if ( zombieStatements != null )
{
//System.err.println("zombieStatements: " + zombieStatements);
destroyAllTrackedStatements( physicalConnection );
}
}
synchronized void deferredDestroyStatement(Object parentConnection, Object pstmt)
{
if (! closed)
{
if (inUseConnections.contains(parentConnection))
{
Set s = (Set) connectionsToZombieStatementSets.get(parentConnection);
if (s == null)
{
s = Collections.synchronizedSet( new HashSet() );
connectionsToZombieStatementSets.put(parentConnection, s);
}
s.add( pstmt );
}
else
{
uncheckedDestroyStatement( pstmt );
}
}
else
uncheckedDestroyStatement( pstmt );
}
// return -1 if unknown
synchronized int countConnectionsInUse()
{ return inUseConnections.size(); }
// under alternative implementation we don't cull Statements
// underneath of Connections in current use
synchronized boolean knownInUse(Connection pCon)
{ return inUseConnections.contains(pCon); }
// we don't sync 'cuz we're just wrapping
// a sync'ed method
Boolean tvlInUse( Connection pCon )
{ return Boolean.valueOf( knownInUse( pCon ) ); }
synchronized int getNumConnectionsInUse()
{ return inUseConnections.size(); }
synchronized int getNumConnectionsWithDeferredDestroyStatements()
{ return connectionsToZombieStatementSets.keySet().size(); }
synchronized int getNumDeferredDestroyStatements()
{
Set keys = connectionsToZombieStatementSets.keySet();
int sum = 0;
for ( Iterator ii = keys.iterator(); ii.hasNext(); )
{
Object con = ii.next();
Set stmts = (Set) connectionsToZombieStatementSets.get( con );
synchronized ( stmts )
{ sum += (stmts == null ? 0 : stmts.size()); }
}
return sum;
}
private void trackedDestroyStatement( final Object parentConnection, final Object pstmt )
{
//System.err.println("trackedDestroyStatement()");
final class TrackedStatementCloseTask implements Runnable
{
public void run()
{
// debug
//System.err.println("TrackedStatementCloseTask.run()");
synchronized ( CautiousStatementDestructionManager.this )
{
//System.err.println("TrackedStatementCloseTask -- with lock");
final Set stmts = (Set) connectionsToZombieStatementSets.get( parentConnection );
if ( stmts != null )
{
StatementUtils.attemptClose( (PreparedStatement) pstmt );
//System.err.println( "Closed tracked statement: " + pstmt);
boolean removed1 = stmts.remove( pstmt );
assert removed1;
if (stmts.isEmpty())
{
Object removed2 = connectionsToZombieStatementSets.remove( parentConnection );
//assert removed2 != null;
assert removed2 == stmts;
CautiousStatementDestructionManager.this.notifyAll();
//System.err.println( "Notify -- all statements closed after close tracked statements: " + pstmt);
}
//else
//System.err.println("Statements remaining open -- " + stmts);
}
}
//printAllStats();
}
}
Runnable r = new TrackedStatementCloseTask();
if (! closed)
{
//blockingTaskAsyncRunner.postRunnable(r);
deferredStatementDestroyer.postRunnable(r);
//System.err.println("trackedDestroyStatement() -- posted task.");
}
else
{
r.run();
//System.err.println("trackedDestroyStatement() -- closed, so destroying synchronously.");
}
}
private void destroyAllTrackedStatements( final Object parentConnection )
{
//System.err.println("destroyAllTrackedStatements()");
final class TrackedDestroyAllStatementsTask implements Runnable
{
public void run()
{
// debug
//System.err.println("TrackedDestroyAllStatementsTask.run()");
synchronized ( CautiousStatementDestructionManager.this )
{
//System.err.println("TrackedDestroyAllStatementsTask -- with lock");
final Set stmts = (Set) connectionsToZombieStatementSets.remove( parentConnection );
if (stmts != null)
{
//System.err.println("TrackedDestroyAllStatementsTask -- to destroy " + stmts);
for(Iterator ii = stmts.iterator(); ii.hasNext(); )
{
PreparedStatement pstmt = (PreparedStatement) ii.next();
StatementUtils.attemptClose( pstmt );
ii.remove();
}
CautiousStatementDestructionManager.this.notifyAll();
//System.err.println( "Notify -- closed all tracked statements." );
}
//else
//System.err.println("No statements for Connection " + parentConnection + "; with connections: " + connectionsToZombieStatementSets.keySet());
}
//printAllStats();
}
}
Runnable r = new TrackedDestroyAllStatementsTask();
if (! closed)
{
//blockingTaskAsyncRunner.postRunnable(r);
deferredStatementDestroyer.postRunnable(r);
//System.err.println("destroyAllTrackedStatements() -- posted task.");
}
else
{
r.run();
//System.err.println("destroyAllTrackedStatements() -- closed, so destroying synchronously.");
}
}
private Set statementsUnderDestruction( Object parentConnection )
{
assert Thread.holdsLock( this );
return (Set) connectionsToZombieStatementSets.get( parentConnection );
}
}
}