/*
* JBoss, Home of Professional Open Source.
* Copyright 2010, Red Hat Middleware LLC, and individual contributors
* as indicated by the @author tags. See the copyright.txt file in the
* distribution for a full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* 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; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.jboss.jca.core.connectionmanager.pool.mcp;
import org.jboss.jca.common.JBossResourceException;
import org.jboss.jca.core.connectionmanager.listener.ConnectionListener;
import org.jboss.jca.core.connectionmanager.listener.ConnectionListenerFactory;
import org.jboss.jca.core.connectionmanager.listener.ConnectionState;
import org.jboss.jca.core.connectionmanager.pool.SubPoolContext;
import org.jboss.jca.core.connectionmanager.pool.api.Pool;
import org.jboss.jca.core.connectionmanager.pool.api.PoolConfiguration;
import org.jboss.jca.core.connectionmanager.pool.idle.IdleRemover;
import org.jboss.jca.core.connectionmanager.pool.validator.ConnectionValidator;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.Set;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.ConcurrentSkipListSet;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicInteger;
import javax.resource.ResourceException;
import javax.resource.spi.ConnectionRequestInfo;
import javax.resource.spi.ManagedConnection;
import javax.resource.spi.ManagedConnectionFactory;
import javax.resource.spi.RetryableUnavailableException;
import javax.resource.spi.ValidatingManagedConnectionFactory;
import javax.security.auth.Subject;
import org.jboss.logging.Logger;
/**
* A managed connection pool implementation using ArrayBlockingQueue
*
* @author <a href="mailto:jesper.pedersen@jboss.org">Jesper Pedersen</a>
*/
public class ArrayBlockingQueueManagedConnectionPool implements ManagedConnectionPool
{
/** The log */
private Logger log;
/** Whether trace is enabled */
private boolean trace;
/** The managed connection factory */
private ManagedConnectionFactory mcf;
/** The connection listener factory */
private ConnectionListenerFactory clf;
/** The default subject */
private Subject defaultSubject;
/** The default connection request information */
private ConnectionRequestInfo defaultCri;
/** The pool configuration */
private PoolConfiguration poolConfiguration;
/** The pool */
private Pool pool;
/**
* Copy of the maximum size from the pooling parameters.
* Dynamic changes to this value are not compatible with
* the semaphore which cannot change be dynamically changed.
*/
private int maxSize;
/** The available connection event listeners */
private ArrayBlockingQueue<ConnectionListener> cls;
/** The permits used to control who can checkout a connection */
private ConcurrentMap<ConnectionListener, ConnectionListener> permits;
/** The subpool */
private SubPoolContext subPool;
/** The checked out connections */
private final ConcurrentSkipListSet<ConnectionListener> checkedOut =
new ConcurrentSkipListSet<ConnectionListener>();
/** Whether the pool has been started */
private AtomicBoolean started = new AtomicBoolean(false);
/** Whether the pool has been shutdown */
private AtomicBoolean shutdown = new AtomicBoolean(false);
/** the max connections ever checked out **/
private AtomicInteger maxUsedConnections = new AtomicInteger(0);
/**
* Constructor
*/
public ArrayBlockingQueueManagedConnectionPool()
{
}
/**
* {@inheritDoc}
*/
public void initialize(ManagedConnectionFactory mcf, ConnectionListenerFactory clf, Subject subject,
ConnectionRequestInfo cri, PoolConfiguration pc, Pool p, SubPoolContext spc,
Logger log)
{
this.mcf = mcf;
this.clf = clf;
this.defaultSubject = subject;
this.defaultCri = cri;
this.poolConfiguration = pc;
this.maxSize = pc.getMaxSize();
this.pool = p;
this.subPool = spc;
this.log = log;
this.trace = log.isTraceEnabled();
this.cls = new ArrayBlockingQueue<ConnectionListener>(this.maxSize, true);
this.permits = new ConcurrentHashMap<ConnectionListener, ConnectionListener>(this.maxSize);
if (pc.isPrefill())
{
PoolFiller.fillPool(this);
}
reenable();
}
/**
* {@inheritDoc}
*/
public SubPoolContext getSubPool()
{
return subPool;
}
/**
* {@inheritDoc}
*/
public boolean isRunning()
{
return !shutdown.get();
}
/**
* {@inheritDoc}
*/
public boolean isEmpty()
{
return cls.size() == 0 && checkedOut.size() == 0;
}
/**
* {@inheritDoc}
*/
public void reenable()
{
if (poolConfiguration.getIdleTimeout() > 0L)
{
//Register removal support
IdleRemover.registerPool(this, poolConfiguration.getIdleTimeout());
}
if (poolConfiguration.isBackgroundValidation() && poolConfiguration.getBackgroundValidationInterval() > 0)
{
log.debug("Registering for background validation at interval " +
poolConfiguration.getBackgroundValidationInterval());
//Register validation
ConnectionValidator.registerPool(this, poolConfiguration.getBackgroundValidationInterval());
}
shutdown.set(false);
}
private synchronized long getAvailableConnections()
{
int result = maxSize - permits.size();
return (result >= 0) ? result : 0;
}
/**
* {@inheritDoc}
*/
public ConnectionListener getConnection(Subject subject, ConnectionRequestInfo cri) throws ResourceException
{
subject = (subject == null) ? defaultSubject : subject;
cri = (cri == null) ? defaultCri : cri;
ConnectionListener cl = null;
boolean verifyConnectionListener = true;
long startWait = System.currentTimeMillis();
if (getAvailableConnections() > 0)
{
if (shutdown.get())
throw new RetryableUnavailableException("The pool has been shutdown");
cl = cls.peek();
if (cl != null)
{
try
{
cl = cls.poll(poolConfiguration.getBlockingTimeout(), TimeUnit.MILLISECONDS);
}
catch (InterruptedException ie)
{
long end = System.currentTimeMillis() - startWait;
throw new ResourceException("Interrupted while requesting connection! Waited " + end + " ms");
}
}
else
{
try
{
// No, the pool was empty, so we have to make a new one.
cl = createConnectionEventListener(subject, cri);
// Started is atomic, so pool filler won't be scheduled twice
if (!started.getAndSet(true))
{
if (poolConfiguration.getMinSize() > 0)
PoolFiller.fillPool(this);
}
if (trace)
log.trace("supplying new ManagedConnection: " + cl);
verifyConnectionListener = false;
}
catch (Throwable t)
{
log.warn("Throwable while attempting to get a new connection: " + cl, t);
JBossResourceException.rethrowAsResourceException("Unexpected throwable while trying " +
"to create a connection: " + cl, t);
}
}
}
else
{
try
{
cl = cls.poll(poolConfiguration.getBlockingTimeout(), TimeUnit.MILLISECONDS);
if (shutdown.get())
throw new RetryableUnavailableException("The pool has been shutdown");
}
catch (InterruptedException ie)
{
if (!poolConfiguration.isUseFastFail())
{
throw new ResourceException("No ManagedConnections available within configured blocking timeout ( "
+ poolConfiguration.getBlockingTimeout() + " [ms] )");
}
else
{
if (trace)
log.trace("Fast failing for connection attempt. No more attempts will be made to " +
"acquire connection from pool and a new connection will be created immeadiately");
try
{
cl = createConnectionEventListener(subject, cri);
// Started is atomic, so pool filler won't be scheduled twice
if (!started.getAndSet(true))
{
if (poolConfiguration.getMinSize() > 0)
PoolFiller.fillPool(this);
}
if (trace)
log.trace("supplying new ManagedConnection: " + cl);
verifyConnectionListener = false;
}
catch (Throwable t)
{
log.warn("Throwable while attempting to get a new connection: " + cl, t);
JBossResourceException.rethrowAsResourceException("Unexpected throwable while trying to " +
"create a connection: " + cl, t);
}
}
}
}
// Register the connection listener
checkedOut.add(cl);
// Update max used connections
int size = maxSize - permits.size();
if (size > maxUsedConnections.get())
maxUsedConnections.set(size);
if (!verifyConnectionListener)
{
// Register the connection listener with permits
permits.put(cl, cl);
// Return connection listener
return cl;
}
else
{
try
{
Object matchedMC =
mcf.matchManagedConnections(Collections.singleton(cl.getManagedConnection()), subject, cri);
if (matchedMC != null)
{
if (trace)
log.trace("supplying ManagedConnection from pool: " + cl);
// Register the connection listener with permits
permits.put(cl, cl);
// Return connection listener
return cl;
}
// Match did not succeed but no exception was thrown.
// Either we have the matching strategy wrong or the
// connection died while being checked. We need to
// distinguish these cases, but for now we always
// destroy the connection.
log.warn("Destroying connection that could not be successfully matched: " + cl + " for: " + mcf);
checkedOut.remove(cl);
doDestroy(cl);
cl = null;
}
catch (Throwable t)
{
log.warn("Throwable while trying to match ManagedConnection, destroying connection: " + cl, t);
checkedOut.remove(cl);
doDestroy(cl);
cl = null;
JBossResourceException.rethrowAsResourceException("Unexpected throwable while trying " +
"to create a connection: " + cl, t);
}
}
throw new JBossResourceException("This should never happen", new Throwable("STACKTRACE"));
}
/**
* {@inheritDoc}
*/
public void returnConnection(ConnectionListener cl, boolean kill)
{
if (cl.getState() == ConnectionState.DESTROYED)
{
if (trace)
log.trace("ManagedConnection is being returned after it was destroyed" + cl);
if (permits.containsKey(cl))
{
// release connection listener
permits.remove(cl);
}
return;
}
if (trace)
log.trace("putting ManagedConnection back into pool kill=" + kill + " cl=" + cl);
try
{
cl.getManagedConnection().cleanup();
}
catch (ResourceException re)
{
log.warn("ResourceException cleaning up ManagedConnection: " + cl, re);
kill = true;
}
// We need to destroy this one
if (cl.getState() == ConnectionState.DESTROY || cl.getState() == ConnectionState.DESTROYED)
kill = true;
checkedOut.remove(cl);
// This is really an error
if (!kill && cls.size() >= poolConfiguration.getMaxSize())
{
log.warn("Destroying returned connection, maximum pool size exceeded " + cl);
kill = true;
}
// If we are destroying, check the connection is not in the pool
if (kill)
{
// Adrian Brock: A resource adapter can asynchronously notify us that
// a connection error occurred.
// This could happen while the connection is not checked out.
// e.g. JMS can do this via an ExceptionListener on the connection.
// I have twice had to reinstate this line of code, PLEASE DO NOT REMOVE IT!
cls.remove(cl);
}
// return to the pool
else
{
cl.used();
if (!cls.contains(cl))
{
try
{
cls.put(cl);
}
catch (InterruptedException ie)
{
cl.setState(ConnectionState.DESTROY);
kill = true;
}
}
else
{
log.warn("Attempt to return connection twice (ignored): " + cl, new Throwable("STACKTRACE"));
}
}
if (permits.containsKey(cl))
{
// release connection listener
permits.remove(cl);
}
if (kill)
{
if (trace)
log.trace("Destroying returned connection " + cl);
doDestroy(cl);
}
}
/**
* {@inheritDoc}
*/
public void flush()
{
ArrayList<ConnectionListener> destroy = null;
if (trace)
log.trace("Flushing pool checkedOut=" + checkedOut + " inPool=" + cls);
// Mark checked out connections as requiring destruction
for (Iterator<ConnectionListener> i = checkedOut.iterator(); i.hasNext();)
{
ConnectionListener cl = i.next();
if (trace)
log.trace("Flush marking checked out connection for destruction " + cl);
cl.setState(ConnectionState.DESTROY);
}
// Destroy connections in the pool
ConnectionListener cl = cls.poll();
while (cl != null)
{
if (destroy == null)
destroy = new ArrayList<ConnectionListener>();
destroy.add(cl);
cl = cls.poll();
}
// We need to destroy some connections
if (destroy != null)
{
for (int i = 0; i < destroy.size(); ++i)
{
ConnectionListener l = destroy.get(i);
if (trace)
log.trace("Destroying flushed connection " + l);
doDestroy(l);
}
// We destroyed something, check the minimum.
if (!shutdown.get() && poolConfiguration.getMinSize() > 0)
PoolFiller.fillPool(this);
}
}
/**
* {@inheritDoc}
*/
public void removeIdleConnections()
{
ArrayList<ConnectionListener> destroy = null;
long timeout = System.currentTimeMillis() - poolConfiguration.getIdleTimeout();
boolean cont = true;
while (cont)
{
// Check the first in the list
ConnectionListener cl = cls.peek();
if (cl != null && cl.isTimedOut(timeout) && shouldRemove())
{
// We need to destroy this one
if (destroy == null)
destroy = new ArrayList<ConnectionListener>(1);
cl = cls.poll();
if (cl != null)
{
destroy.add(cl);
}
else
{
// The connection list were empty
cont = false;
}
}
else
{
// They were inserted chronologically, so if this one
// isn't timed out, following ones won't be either.
cont = false;
}
}
// We found some connections to destroy
if (destroy != null)
{
for (int i = 0; i < destroy.size(); ++i)
{
ConnectionListener cl = destroy.get(i);
if (trace)
log.trace("Destroying timedout connection " + cl);
doDestroy(cl);
}
// We destroyed something, check the minimum.
if (!shutdown.get() && poolConfiguration.getMinSize() > 0)
PoolFiller.fillPool(this);
// Empty sub-pool
if (pool != null)
pool.emptySubPool(this);
}
}
/**
* {@inheritDoc}
*/
public void shutdown()
{
shutdown.set(true);
IdleRemover.unregisterPool(this);
ConnectionValidator.unregisterPool(this);
flush();
}
/**
* {@inheritDoc}
*/
public void fillToMin()
{
while (poolConfiguration.getMinSize() - (cls.size() + checkedOut.size()) > 0)
{
if (shutdown.get())
return;
// Create a connection to fill the pool
ConnectionListener cl = null;
boolean destroy = false;
try
{
cl = createConnectionEventListener(defaultSubject, defaultCri);
if ((checkedOut.size() + cls.size()) < poolConfiguration.getMinSize())
{
if (trace)
log.trace("Filling pool cl=" + cl);
if (!cls.offer(cl))
{
log.debug("Connection couldn't be inserted during fillToMin");
destroy = true;
}
}
else
{
log.debug("MinSize reached during fillToMin");
destroy = true;
}
}
catch (ResourceException re)
{
log.warn("Unable to fill pool ", re);
destroy = true;
}
finally
{
if (destroy)
{
if (cl != null)
{
doDestroy(cl);
}
break;
}
}
}
}
/**
* Create a connection event listener
*
* @param subject the subject
* @param cri the connection request information
* @return the new listener
* @throws ResourceException for any error
*/
private ConnectionListener createConnectionEventListener(Subject subject, ConnectionRequestInfo cri)
throws ResourceException
{
ManagedConnection mc = mcf.createManagedConnection(subject, cri);
try
{
return clf.createConnectionListener(mc, this);
}
catch (ResourceException re)
{
mc.destroy();
throw re;
}
}
/**
* Destroy a connection
*
* @param cl the connection to destroy
*/
private void doDestroy(ConnectionListener cl)
{
if (cl.getState() == ConnectionState.DESTROYED)
{
log.trace("ManagedConnection is already destroyed " + cl);
return;
}
cl.setState(ConnectionState.DESTROYED);
try
{
cl.getManagedConnection().destroy();
}
catch (Throwable t)
{
log.debug("Exception destroying ManagedConnection " + cl, t);
}
}
private boolean shouldRemove()
{
boolean remove = true;
if (poolConfiguration.isStrictMin())
{
remove = cls.size() > poolConfiguration.getMinSize();
if (trace)
log.trace("StrictMin is active. Current connection will be removed is " + remove);
}
return remove;
}
/**
* {@inheritDoc}
*/
public void validateConnections() throws Exception
{
if (trace)
log.trace("Attempting to validate connections for pool " + this);
boolean anyDestroyed = false;
try
{
while (true)
{
ConnectionListener cl = null;
boolean destroyed = false;
if (cls.size() == 0)
{
break;
}
cl = removeForFrequencyCheck();
if (cl == null)
{
break;
}
try
{
Set candidateSet = Collections.singleton(cl.getManagedConnection());
if (mcf instanceof ValidatingManagedConnectionFactory)
{
ValidatingManagedConnectionFactory vcf = (ValidatingManagedConnectionFactory) mcf;
candidateSet = vcf.getInvalidConnections(candidateSet);
if (candidateSet != null && candidateSet.size() > 0)
{
if (cl.getState() != ConnectionState.DESTROY)
{
doDestroy(cl);
destroyed = true;
anyDestroyed = true;
}
}
}
else
{
log.warn("Warning: Background validation was specified with a non compliant " +
"ManagedConnectionFactory interface.");
}
}
finally
{
if (!destroyed)
{
if (!returnForFrequencyCheck(cl))
anyDestroyed = true;
}
}
}
}
finally
{
if (anyDestroyed && !shutdown.get() && poolConfiguration.getMinSize() > 0)
{
PoolFiller.fillPool(this);
}
}
}
/**
* Remove a connection to the pool for a frequency check
* @return A connection; <code>null</code> if no connections needs to be checked
*/
private ConnectionListener removeForFrequencyCheck()
{
log.debug("Checking for connection within frequency");
ConnectionListener result = null;
Iterator<ConnectionListener> iter = cls.iterator();
while (result == null && iter.hasNext())
{
ConnectionListener cl = iter.next();
long lastCheck = cl.getLastValidatedTime();
if ((System.currentTimeMillis() - lastCheck) >= poolConfiguration.getBackgroundValidationInterval())
{
result = cl;
cls.remove(cl);
}
}
return result;
}
/**
* Return a connection to the pool
* @param cl The connection
* @return <code>True</code> if the connection was returned; otherwise <code>false</code>
*/
private boolean returnForFrequencyCheck(ConnectionListener cl)
{
log.debug("Returning for connection within frequency: " + cl);
if (cl == null)
return true;
cl.setLastValidatedTime(System.currentTimeMillis());
if (!cls.offer(cl))
{
log.debug("Connection couldn't be returned");
doDestroy(cl);
return false;
}
return true;
}
}