/*
 * JBoss, Home of Professional Open Source.
 * Copyright 2006, 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.resource.connectionmanager;

import java.util.ArrayList;
import java.util.Collection;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;
import java.util.concurrent.atomic.AtomicBoolean;

import javax.management.ObjectName;
import javax.naming.InitialContext;
import javax.resource.ResourceException;
import javax.resource.spi.ConnectionEvent;
import javax.resource.spi.ConnectionRequestInfo;
import javax.resource.spi.LocalTransaction;
import javax.resource.spi.ManagedConnection;
import javax.security.auth.Subject;
import javax.transaction.RollbackException;
import javax.transaction.Status;
import javax.transaction.Synchronization;
import javax.transaction.SystemException;
import javax.transaction.Transaction;
import javax.transaction.TransactionManager;
import javax.transaction.xa.XAException;
import javax.transaction.xa.XAResource;
import javax.transaction.xa.Xid;

import org.jboss.logging.Logger;
import org.jboss.resource.JBossResourceException;
import org.jboss.resource.connectionmanager.xa.XAResourceWrapperImpl;
import org.jboss.tm.LastResource;
import org.jboss.tm.TransactionTimeoutConfiguration;
import org.jboss.tm.TxUtils;
import org.jboss.util.NestedRuntimeException;

/**
 * The TxConnectionManager is a JBoss ConnectionManager
 * implementation for jca adapters implementing LocalTransaction and XAResource support.
 * 
 * It implements a ConnectionEventListener that implements XAResource to
 * manage transactions through the Transaction Manager. To assure that all
 * work in a local transaction occurs over the same ManagedConnection, it
 * includes a xid to ManagedConnection map.  When a Connection is requested
 * or a transaction started with a connection handle in use, it checks to
 * see if a ManagedConnection already exists enrolled in the global
 * transaction and uses it if found. Otherwise a free ManagedConnection
 * has its LocalTransaction started and is used.  From the
 * BaseConnectionManager2, it includes functionality to obtain managed
 * connections from
 * a ManagedConnectionPool mbean, find the Subject from a SubjectSecurityDomain,
 * and interact with the CachedConnectionManager for connections held over
 * transaction and method boundaries.  Important mbean references are to a
 * ManagedConnectionPool supplier (typically a JBossManagedConnectionPool), and a
 * RARDeployment representing the ManagedConnectionFactory.
 *
 * This connection manager has to perform the following operations:
 *
 * 1. When an application component requests a new ConnectionHandle,
 *    it must find a ManagedConnection, and make sure a
 *    ConnectionEventListener is registered. It must inform the
 *    CachedConnectionManager that a connection handle has been given
 *    out. It needs to count the number of handles for each
 *    ManagedConnection.  If there is a current transaction, it must
 *    enlist the ManagedConnection's LocalTransaction in the transaction
 *    using the ConnectionEventListeners XAResource XAResource implementation.
 * Entry point: ConnectionManager.allocateConnection.
 * written.
 *
 * 2. When a ConnectionClosed event is received from the
 *    ConnectionEventListener, it must reduce the handle count.  If
 *    the handle count is zero, the XAResource should be delisted from
 *    the Transaction, if any. The CachedConnectionManager must be
 *    notified that the connection is closed.
 * Entry point: ConnectionEventListener.ConnectionClosed.
 * written
 *
 *3. When a transaction begun notification is received from the
 * UserTransaction (via the CachedConnectionManager, all
 * managedConnections associated with the current object must be
 * enlisted in the transaction.
 *  Entry point: (from
 * CachedConnectionManager)
 * ConnectionCacheListener.transactionStarted(Transaction,
 * Collection). The collection is of ConnectionRecord objects.
 * written.
 *
 * 5. When an "entering object" notification is received from the
 * CachedConnectionInterceptor, all the connections for the current
 * object must be associated with a ManagedConnection.  if there is a
 * Transaction, the XAResource must be enlisted with it.
 *  Entry point: ConnectionCacheListener.reconnect(Collection conns) The Collection
 * is of ConnectionRecord objects.
 * written.
 *
 * 6. When a "leaving object" notification is received from the
 * CachedConnectionInterceptor, all the managedConnections for the
 * current object must have their XAResources delisted from the
 * current Transaction, if any, and cleanup called on each
 * ManagedConnection.
 * Entry point: ConnectionCacheListener.disconnect(Collection conns).
 * written.
 *
 * @author <a href="mailto:d_jencks@users.sourceforge.net">David Jencks</a>
 * @author <a href="mailto:adrian@jboss.org">Adrian Brock</a>
 * @author <a href="weston.price@jboss.com">Weston Price</a>
 * @version $Revision: 77961 $
 */
public class TxConnectionManager extends BaseConnectionManager2 implements TxConnectionManagerMBean
{
   private static final Throwable FAILED_TO_ENLIST = new Throwable("Unabled to enlist resource, see the previous warnings."); 

   private ObjectName transactionManagerService;
   
   //use the object name, please
   private String tmName;

   private TransactionManager tm;

   private boolean interleaving;

   private boolean localTransactions;
   
   private int xaResourceTimeout = 0;
   
   private boolean padXid;
   
   private boolean wrapXAResource;

   private Boolean isSameRMOverrideValue;
   
   protected static void rethrowAsSystemException(String context, Transaction tx, Throwable t)
      throws SystemException
   {
      if (t instanceof SystemException)
         throw (SystemException) t;
      if (t instanceof RuntimeException)
         throw (RuntimeException) t;
      if (t instanceof Error)
         throw (Error) t;
      if (t instanceof RollbackException)
         throw new IllegalStateException(context + " tx=" + tx + " marked for rollback.");
      throw new NestedRuntimeException(context + " tx=" + tx + " got unexpected error ", t);
   }
   
   /**
    * Default managed TxConnectionManager constructor for mbean instances.
    */
   public TxConnectionManager()
   {
   }

   /**
    * Creates a new <code>TxConnectionManager</code> instance.
    * for TESTING ONLY!!! not a managed constructor!!
    * 
    * @param ccm a <code>CachedConnectionManager</code> value
    * @param poolingStrategy a <code>ManagedConnectionPool</code> value
    * @param tm a <code>TransactionManager</code> value
    */
   public TxConnectionManager (final CachedConnectionManager ccm,
                               final ManagedConnectionPool poolingStrategy,
                               final TransactionManager tm)
   {
      super(ccm, poolingStrategy);
      this.tm = tm;
   }

   public ObjectName getTransactionManagerService()
   {
      return transactionManagerService;
   }

   public void setTransactionManagerService(ObjectName transactionManagerService)
   {
      this.transactionManagerService = transactionManagerService;
   }

   /**
    * @deprecated
    */
   public void setTransactionManager(final String tmName)
   {
      this.tmName = tmName;
   }

   /**
    * @deprecated
    */
   public String getTransactionManager()
   {
      return this.tmName;
   }

   public TransactionManager getTransactionManagerInstance()
   {
      return tm;
   }

   public void setTransactionManagerInstance(TransactionManager tm)
   {
      this.tm = tm;
   }

   @Deprecated
   public boolean isTrackConnectionByTx()
   {
      log.warn("isTrackConnectionByTx() is deprecated in favor of isInterleaving()");
      return !isInterleaving();
   }

   @Deprecated
   public void setTrackConnectionByTx(boolean trackConnectionByTx)
   {
      log.warn("setTrackConnectionByTx(boolean value) is deprecated in favor of setInterleaving(boolean value)");
      setInterleaving(!trackConnectionByTx);
   }

   public boolean isInterleaving()
   {
      return interleaving;
   }
   
   public void setInterleaving(boolean value)
   {
      this.interleaving = value;
   }
   
   public boolean isLocalTransactions()
   {
      return localTransactions;
   }

   public void setLocalTransactions(boolean localTransactions)
   {
      this.localTransactions = localTransactions;
      if (localTransactions)
         setInterleaving(false);
   }

   public int getXAResourceTransactionTimeout()
   {
      return xaResourceTimeout;
   }
   
   public void setXAResourceTransactionTimeout(int timeout)
   {
      this.xaResourceTimeout = timeout;
   }
   
   /**
    * Get the IsSameRMOverrideValue value.
    * 
    * @return the IsSameRMOverrideValue value.
    */
   public Boolean getIsSameRMOverrideValue()
   {
      return isSameRMOverrideValue;
   }
   
   public boolean getWrapXAResource()
   {      
      return wrapXAResource;      
   }
   
   public void setWrapXAResource(boolean useXAWrapper)
   {
      this.wrapXAResource = useXAWrapper;
      
   }
   
   public boolean getPadXid()
   {
      return this.padXid;
      
   }
   
   public void setPadXid(boolean padXid)
   {
      this.padXid = padXid;
   }
   /**
    * Set the IsSameRMOverrideValue value.
    * 
    * @param isSameRMOverrideValue The new IsSameRMOverrideValue value.
    */
   public void setIsSameRMOverrideValue(Boolean isSameRMOverrideValue)
   {
      this.isSameRMOverrideValue = isSameRMOverrideValue;
   }
   
   public long getTimeLeftBeforeTransactionTimeout(boolean errorRollback) throws RollbackException
   {
      if (tm == null)
         throw new IllegalStateException("No transaction manager: " + ccmName);
      if (tm instanceof TransactionTimeoutConfiguration)
         return ((TransactionTimeoutConfiguration) tm).getTimeLeftBeforeTransactionTimeout(errorRollback);
      return -1;
   }

   @Override
   public void checkTransactionActive() throws RollbackException, SystemException
   {
      if (tm == null)
         throw new IllegalStateException("No transaction manager: " + ccmName);
      Transaction tx = tm.getTransaction();
      if (tx != null)
      {
         int status = tx.getStatus();
         // Only allow states that will actually succeed
         if (status != Status.STATUS_ACTIVE && status != Status.STATUS_PREPARING && status != Status.STATUS_PREPARED && status != Status.STATUS_COMMITTING)
            throw new RollbackException("Transaction " + tx + " cannot proceed " + TxUtils.getStatusAsString(status));
      }
   }

   protected void startService() throws Exception
   {
      if (transactionManagerService != null)
         tm = (TransactionManager)getServer().getAttribute(transactionManagerService, "TransactionManager");
      else
      {
         log.warn("----------------------------------------------------------");
         log.warn("----------------------------------------------------------");
         log.warn("Please change your datasource setup to use <depends optional-attribute-name\"TransactionManagerService\">jboss:service=TransactionManager</depends>");
         log.warn("instead of <attribute name=\"TransactionManager\">java:/TransactionManager</attribute>");
         log.warn("Better still, use a *-ds.xml file");
         log.warn("----------------------------------------------------------");
         log.warn("----------------------------------------------------------");
         tm = (TransactionManager)new InitialContext().lookup(tmName);
      }
      
      
      super.startService();
   }

   protected void stopService() throws Exception
   {
      this.tm = null;
      super.stopService();
   }

   public ConnectionListener getManagedConnection(Subject subject, ConnectionRequestInfo cri)
      throws ResourceException
   {
      Transaction trackByTransaction = null;
      try
      {
         Transaction tx = tm.getTransaction();
         if (tx != null && TxUtils.isActive(tx) == false)
            throw new ResourceException("Transaction is not active: tx=" + tx);
         if (!interleaving)
            trackByTransaction = tx;
      }
      catch (Throwable t)
      {
         JBossResourceException.rethrowAsResourceException("Error checking for a transaction.", t);
      }

      if (trace)
         log.trace("getManagedConnection interleaving=" + interleaving + " tx=" + trackByTransaction);
      return super.getManagedConnection(trackByTransaction, subject, cri);
   }

   public void transactionStarted(Collection crs) throws SystemException
   {
      Set cls = new HashSet();
      for (Iterator i = crs.iterator(); i.hasNext(); )
      {
         ConnectionRecord cr = (ConnectionRecord)i.next();
         ConnectionListener cl = cr.cl;
         if (!cls.contains(cl))
         {
            cls.add(cl);
            cl.enlist();
         }
      }
   }

   protected void managedConnectionReconnected(ConnectionListener cl) throws ResourceException
   {
      try
      {
         cl.enlist();
      }
      catch (Throwable t)
      {
         if (trace)
            log.trace("Could not enlist in transaction on entering meta-aware object! " + cl, t);
         throw new JBossResourceException("Could not enlist in transaction on entering meta-aware object!", t);
      }
   }

   protected void managedConnectionDisconnected(ConnectionListener cl) throws ResourceException
   {
      Throwable throwable = null;
      try
      {
         cl.delist();
      }
      catch (Throwable t)
      {
         throwable = t;
      }

      //if there are no more handles and tx is complete, we can return to pool.
      if (cl.isManagedConnectionFree())
      {
         if (trace)
            log.trace("Disconnected isManagedConnectionFree=true" + " cl=" + cl);
         returnManagedConnection(cl, false);
      }
      else if (trace)
      {
         log.trace("Disconnected isManagedConnectionFree=false" + " cl=" + cl);
      }

      // Rethrow the error
      if (throwable != null)
         JBossResourceException.rethrowAsResourceException("Could not delist resource, probably a transaction rollback? ", throwable);      
   }

   public ConnectionListener createConnectionListener(ManagedConnection mc, Object context)
      throws ResourceException
   {
      XAResource xaResource = null;
      
      if (localTransactions)
      {
         xaResource = new LocalXAResource(log);
    
         if (xaResourceTimeout != 0)
            log.debug("XAResource transaction timeout cannot be set for local transactions: " + getJndiName());
      }
      
      else
      {
         
         if(wrapXAResource)
         {
            String eisProductName = null;
            String eisProductVersion = null;

            try
            {
               eisProductName = mc.getMetaData().getEISProductName();
               eisProductVersion = mc.getMetaData().getEISProductVersion();
            }
            catch (ResourceException re)
            {
               // Ignore
            }

            log.trace("Generating XAResourceWrapper for TxConnectionManager" + this);
            xaResource = new XAResourceWrapperImpl(mc.getXAResource(), padXid, isSameRMOverrideValue, eisProductName, eisProductVersion);
         }
         
         else
         {
            log.trace("Not wrapping XAResource.");
            xaResource = mc.getXAResource();
         }
                                
         if (xaResourceTimeout != 0)
         {
            try
            {
               if (xaResource.setTransactionTimeout(xaResourceTimeout) == false)
                  log.debug("XAResource does not support transaction timeout configuration: " + getJndiName());
            }
            catch (XAException e)
            {
               throw new JBossResourceException("Unable to set XAResource transaction timeout: " + getJndiName(), e);
            }
         }
      }

      ConnectionListener cli = new TxConnectionEventListener(mc, poolingStrategy, context, log, xaResource);
      mc.addConnectionEventListener(cli);
      return cli;
   }

   public boolean isTransactional()
   {
      return TxUtils.isCompleted(tm) == false;
   }

   // implementation of javax.resource.spi.ConnectionEventListener interface
   //there is one of these for each ManagedConnection instance.  It lives as long as the ManagedConnection.
   protected class TxConnectionEventListener
      extends BaseConnectionManager2.BaseConnectionEventListener
   {
      /** Use our own logger to prevent MNFE caused by compiler bug with nested classes. */
      protected Logger log;

      protected TransactionSynchronization transactionSynchronization;
      
      private final XAResource xaResource;

      /** Whether there is a local transaction */
      private AtomicBoolean localTransaction = new AtomicBoolean(false);

      public TxConnectionEventListener(final ManagedConnection mc, final ManagedConnectionPool mcp, final Object context, Logger log, final XAResource xaResource) throws ResourceException
      {
         super(mc, mcp, context, log);
         this.log = log;
         this.xaResource = xaResource;
         
         if (xaResource instanceof LocalXAResource)
            ((LocalXAResource) xaResource).setConnectionListener(this);
      }

      public void enlist() throws SystemException
      {
         // This method is a bit convulted, but it has to be such because
         // there is a race condition in the transaction manager where it
         // unlocks during the enlist of the XAResource. It does this 
         // to avoid distributed deadlocks and to ensure the transaction
         // timeout can fail a badly behaving resource during the enlist.
         //
         // When two threads in the same transaction are trying to enlist 
         // connections they could be from the same resource manager 
         // or even the same connection when tracking the connection by transaction.
         //
         // For the same connection, we only want to do the real enlist once.
         // For two connections from the same resource manager we don't
         // want the join before the initial start request.
         //
         // The solution is to build up a list of unenlisted resources
         // in the TransactionSynchronizer and then choose one of the
         // threads that is contending in the transaction to enlist them
         // in order. The actual order doesn't really matter as it is the
         // transaction manager that calculates the enlist flags and determines
         // whether the XAResource was already enlisted.
         //
         // Once there are no unenlisted resources the threads are released
         // to return the result of the enlistments.
         //
         // In practice, a thread just takes a snapshot to try to avoid one
         // thread having to do all the work. If it did not do them all
         // the next waiting thread will do the next snapshot until there
         // there is either no snapshot or no waiting threads.
         //
         // A downside to this design is a thread could have its resource enlisted by
         // an earlier thread while it enlists some later thread's resource.
         // Since they are all a part of the same transaction, this is probably
         // not a real issue.
         
         // No transaction associated with the thread
         int status = tm.getStatus();
         if (status == Status.STATUS_NO_TRANSACTION)
         {
            if (transactionSynchronization != null && transactionSynchronization.currentTx != null)
            {
               String error = "Attempt to use connection outside a transaction when already a tx!";
               if (trace)
                  log.trace(error + " " + this);
               throw new IllegalStateException(error);
            }
            if (trace)
               log.trace("No transaction, no need to enlist: " + this);
            return;
         }
         
         // Inactive transaction
         Transaction threadTx = tm.getTransaction();
         if (threadTx == null || status != Status.STATUS_ACTIVE)
         {
            String error = "Transaction " + threadTx + " is not active " + TxUtils.getStatusAsString(status);
            if (trace)
               log.trace(error + " cl=" + this);
            throw new IllegalStateException(error);
         }

         if (trace)
            log.trace("Pre-enlist: " + this + " threadTx=" + threadTx);
         
         // Our synchronization 
         TransactionSynchronization ourSynchronization = null;

         // Serializes enlistment when two different threads are enlisting 
         // different connections in the same transaction concurrently
         TransactionSynchronizer synchronizer = null;

         TransactionSynchronizer.lock(threadTx);
         try
         {
            // Interleaving should have an unenlisted transaction
            // TODO: We should be able to do some sharing shouldn't we?
            if (isTrackByTx() == false && transactionSynchronization != null)
            {
               String error = "Can't enlist - already a tx!";
               if (trace)
                  log.trace(error + " " + this);
               throw new IllegalStateException(error);
            }
            
            // Check for different transaction
            if (transactionSynchronization != null && transactionSynchronization.currentTx.equals(threadTx) == false)
            {
               String error = "Trying to change transaction " + threadTx + " in enlist!";
               if (trace)
                  log.trace(error +" " + this);
               throw new IllegalStateException(error);
            }

            // Get the synchronizer
            try
            {
               if (trace)
                  log.trace("Get synchronizer " + this + " threadTx=" + threadTx);
               synchronizer = TransactionSynchronizer.getRegisteredSynchronizer(threadTx);
            }
            catch (Throwable t)
            {
               setTrackByTx(false);
               rethrowAsSystemException("Cannot register synchronization", threadTx, t);
            }

            // First time through, create a transaction synchronization
            if (transactionSynchronization == null)
            {
               TransactionSynchronization synchronization = new TransactionSynchronization(threadTx, isTrackByTx());
               synchronizer.addUnenlisted(synchronization);
               transactionSynchronization = synchronization;
            }
            ourSynchronization = transactionSynchronization;
         }
         finally
         {
            TransactionSynchronizer.unlock(threadTx);
         }

         // Perform the enlistment(s)
         ArrayList unenlisted = synchronizer.getUnenlisted();
         if (unenlisted != null)
         {
            try
            {
               for (int i = 0; i < unenlisted.size(); ++i)
               {
                  TransactionSynchronization sync = (TransactionSynchronization) unenlisted.get(i);
                  if (sync.enlist())
                     synchronizer.addEnlisted(sync);
               }
            }
            finally
            {
               synchronizer.enlisted();
            }
         }
         
         // What was the result of our enlistment?
         if (trace)
            log.trace("Check enlisted " + this + " threadTx=" + threadTx);
         ourSynchronization.checkEnlisted();
      }

      public void delist() throws ResourceException
      {
         if (trace)
            log.trace("delisting " + this);

         try
         {
            if (isTrackByTx() == false && transactionSynchronization != null)
            {
               Transaction tx = transactionSynchronization.currentTx;
               TransactionSynchronization synchronization = transactionSynchronization;
               transactionSynchronization = null;
               if (TxUtils.isUncommitted(tx))
               {
                  TransactionSynchronizer synchronizer = TransactionSynchronizer.getRegisteredSynchronizer(tx);
                  if (synchronization.enlisted)
                     synchronizer.removeEnlisted(synchronization);
                  if (tx.delistResource(getXAResource(), XAResource.TMSUSPEND) == false)
                     throw new ResourceException("Failure to delist resource: " + this);
               }
            }
         }
         catch (Throwable t)
         {
            JBossResourceException.rethrowAsResourceException("Error in delist!", t);
         }
      }

      //local will return this, xa will return one from mc.
      protected XAResource getXAResource()
      {
         return xaResource;
      }

      public void connectionClosed(ConnectionEvent ce)
      {
         if (trace)
            log.trace("connectionClosed called mc=" + this.getManagedConnection());
         if (this.getManagedConnection() != (ManagedConnection)ce.getSource())
            throw new IllegalArgumentException("ConnectionClosed event received from wrong ManagedConnection! Expected: " + this.getManagedConnection() + ", actual: " + ce.getSource());
         try
         {
            getCcm().unregisterConnection(TxConnectionManager.this, ce.getConnectionHandle());
         }
         catch (Throwable t)
         {
            log.info("throwable from unregister connection", t);
         }

         try
         {
            if (wasFreed(ce.getConnectionHandle()))
            {
               delist();
               if (trace)
                  log.trace("isManagedConnectionFree=true mc=" + this.getManagedConnection());
               returnManagedConnection(this, false);
            }
            else
            {
               if (trace)
                  log.trace("isManagedConnectionFree=false mc=" + this.getManagedConnection());
            }
         }
         catch (Throwable t)
         {
            log.error("Error while closing connection handle!", t);
            returnManagedConnection(this, true);
         }
      }

      public void localTransactionStarted(ConnectionEvent ce)
      {
         localTransaction.set(true);
      }

      public void localTransactionCommitted(ConnectionEvent ce)
      {
         localTransaction.set(false);
      }

      public void localTransactionRolledback(ConnectionEvent ce)
      {
         localTransaction.set(false);
      }

      public void tidyup() throws ResourceException
      {
         // We have a hanging transaction
         if (localTransaction.get())
         {
            LocalTransaction local = null;
            ManagedConnection mc = getManagedConnection();
            try
            {
               local = mc.getLocalTransaction();
            }
            catch (Throwable t)
            {
               JBossResourceException.rethrowAsResourceException("Unfinished local transaction - error getting local transaction from " + this, t);
            }
            if (local == null)
               throw new ResourceException("Unfinished local transaction but managed connection does not provide a local transaction. " + this);
            else
            {
               local.rollback();
               log.debug("Unfinished local transaction was rolled back." + this);
            }
         }
      }

      public void connectionErrorOccurred(ConnectionEvent ce)
      {
         transactionSynchronization = null;
         super.connectionErrorOccurred(ce);
      }

      //Important method!!
      public boolean isManagedConnectionFree()
      {
         if (isTrackByTx() && transactionSynchronization != null)
            return false;
         return super.isManagedConnectionFree();
      }

      /**
       * This method changes the number of handles or 
       * the track-by-tx value depending on the parameter passed in
       * @param handle The handle; if <code>null</code> track-by-tx is changed
       * @return True if the managed connection was freed
       */
      synchronized boolean wasFreed(Object handle)
      {
         if (handle != null)
         {
            if (isManagedConnectionFree())
            {
               // This shouldn't really happen now all the state is changed atomically
               return false;
            }

            // Change the number of handles
            unregisterAssociation(this, handle);
         }
         else
         {
            if (!isTrackByTx())
            {
               // Only change the state once
               return false;
            }

            // Set track-by-tx to false
            setTrackByTx(false);
         }
         
         // Return if the managed connection was just freed
         return isManagedConnectionFree();
      }
      
      private class TransactionSynchronization implements Synchronization
      {
         /** Transaction */
         private Transaction currentTx;
         
         /** This is the status when we were registered */
         private boolean wasTrackByTx;

         /** Whether we are enlisted */
         private boolean enlisted = false;
         
         /** Any error during enlistment */
         private Throwable enlistError;
         
         /**
          * Create a new TransactionSynchronization.
          * 
          * @param trackByTx whether this is track by connection
          */
         public TransactionSynchronization(Transaction tx, boolean trackByTx)
         {
            this.currentTx = tx;
            wasTrackByTx = trackByTx;
         }
         
         /**
          * Get the result of the enlistment
          * 
          * @throws SystemExeption for any error
          */
         public void checkEnlisted() throws SystemException
         {
            if (enlistError != null)
            {
               String error = "Error enlisting resource in transaction=" + currentTx;
               if (trace)
                  log.trace(error + " " + TxConnectionEventListener.this);

               // Wrap the error to give a reasonable stacktrace since the resource
               // could have been enlisted by a different thread
               if (enlistError == FAILED_TO_ENLIST)
                  throw new SystemException(FAILED_TO_ENLIST + " tx=" + currentTx);
               else
               {
                  SystemException e = new SystemException(error);
                  e.initCause(enlistError);
                  throw e;
               }
            }
            if (enlisted == false)
            {
               String error = "Resource is not enlisted in transaction=" + currentTx;
               if (trace)
                  log.trace(error + " " + TxConnectionEventListener.this);
               throw new IllegalStateException("Resource was not enlisted.");
            }
         }
         
         /**
          * Enlist the resource
          * 
          * @return true when enlisted, false otherwise
          */
         public boolean enlist()
         {
            if (trace)
               log.trace("Enlisting resource " + TxConnectionEventListener.this);
            try
            {
               XAResource resource = getXAResource();
               if (false == currentTx.enlistResource(resource))
                  enlistError = FAILED_TO_ENLIST;
            }
            catch (Throwable t)
            {
               enlistError = t;
            }

            synchronized (this)
            {
               if (enlistError != null)
               {
                  if (trace)
                     log.trace("Failed to enlist resource " + TxConnectionEventListener.this, enlistError);
                  setTrackByTx(false);
                  transactionSynchronization = null;
                  return false;
               }
               
               if (trace)
                  log.trace("Enlisted resource " + TxConnectionEventListener.this);
               enlisted = true;
               return true;
            }
         }
         
         public void beforeCompletion()
         {
         }

         public void afterCompletion(int status)
         {
            // The connection got destroyed during the transaction
            if (getState() == DESTROYED)
               return;
            
            // Are we still in the original transaction?
            if (this.equals(transactionSynchronization) == false)
            {
               // If we are interleaving transactions we have nothing to do
               if (wasTrackByTx == false)
                  return;
               else
               {
                  // There is something wrong with the pooling
                  String message = "afterCompletion called with wrong tx! Expected: " + this + ", actual: " + transactionSynchronization;
                  IllegalStateException e = new IllegalStateException(message);
                  log.error("There is something wrong with the pooling?", e);
               }
            }
            // "Delist"
            transactionSynchronization = null;
            // This is where we close when doing track by transaction
            if (wasTrackByTx)
            {
               if (trace)
                  log.trace("afterCompletion(" + status + ") isTrackByTx=" + isTrackByTx() + " for " + TxConnectionEventListener.this);

               if (wasFreed(null))
                  returnManagedConnection(TxConnectionEventListener.this, false);
            }
         }
         
         public String toString()
         {
            StringBuffer buffer = new StringBuffer();
            buffer.append("TxSync").append(System.identityHashCode(this));
            buffer.append("{tx=").append(currentTx);
            buffer.append(" wasTrackByTx=").append(wasTrackByTx);
            buffer.append(" enlisted=").append(enlisted);
            buffer.append("}");
            return buffer.toString();
         }
      }
      
      // For debugging
      protected void toString(StringBuffer buffer)
      {
         buffer.append(" xaResource=").append(xaResource);
         buffer.append(" txSync=").append(transactionSynchronization);
      }
   }

   private class LocalXAResource implements XAResource, LastResource
   {
      protected Logger log;

      private ConnectionListener cl;

      /**
       * <code>warned</code> is set after one warning about a local participant
       * in a multi-branch jta transaction is logged.
       *
       */
      private boolean warned = false;

      private Xid currentXid;

      public LocalXAResource(final Logger log)
      {
         this.log = log;
      }

      void setConnectionListener(ConnectionListener cl)
      {
         this.cl = cl;
      }

      // implementation of javax.transaction.xa.XAResource interface

      public void start(Xid xid, int flags) throws XAException
      {
         if (trace)
            log.trace("start, xid: " + xid + ", flags: " + flags);
         if (currentXid  != null && flags == XAResource.TMNOFLAGS)
            throw new JBossLocalXAException("Trying to start a new tx when old is not complete! old: " + currentXid  + ", new " + xid + ", flags " + flags, XAException.XAER_PROTO);
         if (currentXid  == null && flags != XAResource.TMNOFLAGS)
            throw new JBossLocalXAException("Trying to start a new tx with wrong flags!  new " + xid + ", flags " + flags, XAException.XAER_PROTO);
         if (currentXid == null)
         {
            try
            {
               cl.getManagedConnection().getLocalTransaction().begin();
            }
            catch (ResourceException re)
            {
               throw new JBossLocalXAException("Error trying to start local tx: ", XAException.XAER_RMERR, re);
            }
            catch (Throwable t)
            {
               throw new JBossLocalXAException("Throwable trying to start local transaction!", XAException.XAER_RMERR, t);
            }

            currentXid = xid;
         }
      }

      public void end(Xid xid, int flags) throws XAException
      {
         if (trace)
            log.trace("end on xid: " + xid + " called with flags " + flags);
      }

      public void commit(Xid xid, boolean onePhase) throws XAException
      {
         if (xid.equals(currentXid) == false)
            throw new JBossLocalXAException("wrong xid in commit: expected: " + currentXid + ", got: " + xid, XAException.XAER_PROTO);
         currentXid = null;
         try
         {
            cl.getManagedConnection().getLocalTransaction().commit();
         }
         catch (ResourceException re)
         {
            returnManagedConnection(cl, true);
            if (trace)
               log.trace("commit problem: ", re);
            throw new JBossLocalXAException("could not commit local tx", XAException.XA_RBROLLBACK, re);
         }
      }

      public void forget(Xid xid) throws XAException
      {
         throw new JBossLocalXAException("forget not supported in local tx", XAException.XAER_RMERR);
      }

      public int getTransactionTimeout() throws XAException
      {
         // TODO: implement this javax.transaction.xa.XAResource method
         return 0;
      }

      public boolean isSameRM(XAResource xaResource) throws XAException
      {
         return xaResource == this;
      }

      public int prepare(Xid xid) throws XAException
      {
         if (!warned)
            log.warn("Prepare called on a local tx. Use of local transactions on a jta transaction with more than one branch may result in inconsistent data in some cases of failure.");
         warned = true;
         return XAResource.XA_OK;
      }

      public Xid[] recover(int flag) throws XAException
      {
         throw new JBossLocalXAException("no recover with local-tx only resource managers", XAException.XAER_RMERR);
      }

      public void rollback(Xid xid) throws XAException
      {
         if (xid.equals(currentXid) == false)
            throw new JBossLocalXAException("wrong xid in rollback: expected: " + currentXid + ", got: " + xid, XAException.XAER_PROTO);
         currentXid = null;
         try
         {
            cl.getManagedConnection().getLocalTransaction().rollback();
         }
         catch (ResourceException re)
         {
            returnManagedConnection(cl, true);
            if (trace)
               log.trace("rollback problem: ", re);
            throw new JBossLocalXAException("could not rollback local tx", XAException.XAER_RMERR, re);
         }
      }

      public boolean setTransactionTimeout(int seconds) throws XAException
      {
         // TODO: implement this javax.transaction.xa.XAResource method
         return false;
      }
   }
}
