/**
 * Copyright (c) 2004 - 2009 Eike Stepper (Berlin, Germany) and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *    Eike Stepper - initial API and implementation
 *    Simon McDuff - maintenance
 *    Victor Roldan Betancort - maintenance
 */
package org.eclipse.emf.internal.cdo.transaction;

import org.eclipse.emf.cdo.CDOObject;
import org.eclipse.emf.cdo.CDOState;
import org.eclipse.emf.cdo.common.id.CDOID;
import org.eclipse.emf.cdo.common.id.CDOIDAndVersion;
import org.eclipse.emf.cdo.common.id.CDOIDTemp;
import org.eclipse.emf.cdo.common.id.CDOIDUtil;
import org.eclipse.emf.cdo.common.model.CDOModelUtil;
import org.eclipse.emf.cdo.common.model.CDOPackageRegistry;
import org.eclipse.emf.cdo.common.model.CDOPackageUnit;
import org.eclipse.emf.cdo.common.model.EMFUtil;
import org.eclipse.emf.cdo.common.revision.CDORevision;
import org.eclipse.emf.cdo.common.revision.delta.CDOFeatureDelta;
import org.eclipse.emf.cdo.common.revision.delta.CDORevisionDelta;
import org.eclipse.emf.cdo.common.revision.delta.CDORevisionDeltaUtil;
import org.eclipse.emf.cdo.common.util.CDOException;
import org.eclipse.emf.cdo.eresource.CDOResource;
import org.eclipse.emf.cdo.eresource.CDOResourceFolder;
import org.eclipse.emf.cdo.eresource.CDOResourceNode;
import org.eclipse.emf.cdo.eresource.EresourceFactory;
import org.eclipse.emf.cdo.eresource.impl.CDOResourceImpl;
import org.eclipse.emf.cdo.eresource.impl.CDOResourceNodeImpl;
import org.eclipse.emf.cdo.messages.Messages;
import org.eclipse.emf.cdo.spi.common.model.InternalCDOPackageUnit;
import org.eclipse.emf.cdo.spi.common.revision.InternalCDORevisionDelta;
import org.eclipse.emf.cdo.transaction.CDOConflictResolver;
import org.eclipse.emf.cdo.transaction.CDOSavepoint;
import org.eclipse.emf.cdo.transaction.CDOTransaction;
import org.eclipse.emf.cdo.transaction.CDOTransactionConflictEvent;
import org.eclipse.emf.cdo.transaction.CDOTransactionFinishedEvent;
import org.eclipse.emf.cdo.transaction.CDOTransactionHandler;
import org.eclipse.emf.cdo.transaction.CDOTransactionStartedEvent;
import org.eclipse.emf.cdo.util.CDOURIUtil;
import org.eclipse.emf.cdo.view.CDOViewResourcesEvent;

import org.eclipse.emf.internal.cdo.CDOObjectMerger;
import org.eclipse.emf.internal.cdo.CDOStateMachine;
import org.eclipse.emf.internal.cdo.bundle.OM;
import org.eclipse.emf.internal.cdo.util.CompletePackageClosure;
import org.eclipse.emf.internal.cdo.util.FSMUtil;
import org.eclipse.emf.internal.cdo.util.IPackageClosure;
import org.eclipse.emf.internal.cdo.view.CDOViewImpl;

import org.eclipse.net4j.util.ImplementationError;
import org.eclipse.net4j.util.ObjectUtil;
import org.eclipse.net4j.util.WrappedException;
import org.eclipse.net4j.util.event.Notifier;
import org.eclipse.net4j.util.om.trace.ContextTracer;
import org.eclipse.net4j.util.options.OptionsEvent;
import org.eclipse.net4j.util.transaction.TransactionException;

import org.eclipse.emf.common.util.URI;
import org.eclipse.emf.ecore.EPackage;
import org.eclipse.emf.spi.cdo.CDOTransactionStrategy;
import org.eclipse.emf.spi.cdo.InternalCDOObject;
import org.eclipse.emf.spi.cdo.InternalCDOSession;
import org.eclipse.emf.spi.cdo.InternalCDOTransaction;
import org.eclipse.emf.spi.cdo.CDOSessionProtocol.CommitTransactionResult;

import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.core.runtime.NullProgressMonitor;

import java.text.MessageFormat;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.Map.Entry;
import java.util.concurrent.locks.ReentrantLock;

/**
 * @author Eike Stepper
 */
public class CDOTransactionImpl extends CDOViewImpl implements InternalCDOTransaction
{
  private static final ContextTracer TRACER = new ContextTracer(OM.DEBUG_TRANSCTION, CDOTransactionImpl.class);

  /**
   * TODO Optimize by storing an array. See {@link Notifier}.
   */
  private List<CDOTransactionHandler> handlers = new ArrayList<CDOTransactionHandler>(0);

  private CDOSavepointImpl lastSavepoint = new CDOSavepointImpl(this, null);

  private CDOSavepointImpl firstSavepoint = lastSavepoint;

  private boolean dirty;

  private int conflict;

  private long lastCommitTime = CDORevision.UNSPECIFIED_DATE;

  private int lastTemporaryID;

  private CDOTransactionStrategy transactionStrategy;

  /**
   * @since 2.0
   */
  public CDOTransactionImpl()
  {
  }

  /**
   * @since 2.0
   */
  @Override
  public OptionsImpl options()
  {
    return (OptionsImpl)super.options();
  }

  /**
   * @since 2.0
   */
  @Override
  protected OptionsImpl createOptions()
  {
    return new OptionsImpl();
  }

  @Override
  public Type getViewType()
  {
    return Type.TRANSACTION;
  }

  public void addHandler(CDOTransactionHandler handler)
  {
    synchronized (handlers)
    {
      if (!handlers.contains(handler))
      {
        handlers.add(handler);
      }
    }
  }

  public void removeHandler(CDOTransactionHandler handler)
  {
    synchronized (handlers)
    {
      handlers.remove(handler);
    }
  }

  public CDOTransactionHandler[] getHandlers()
  {
    synchronized (handlers)
    {
      return handlers.toArray(new CDOTransactionHandler[handlers.size()]);
    }
  }

  @Override
  public boolean isDirty()
  {
    if (isClosed())
    {
      return false;
    }

    return dirty;
  }

  @Override
  public boolean hasConflict()
  {
    checkActive();
    return conflict != 0;
  }

  public void setConflict(InternalCDOObject object)
  {
    ConflictEvent event = new ConflictEvent(object, conflict == 0);
    ++conflict;
    fireEvent(event);
  }

  /**
   * @since 2.0
   */
  public Set<CDOObject> getConflicts()
  {
    Set<CDOObject> conflicts = new HashSet<CDOObject>();
    for (CDOObject object : getDirtyObjects().values())
    {
      if (object.cdoConflict())
      {
        conflicts.add(object);
      }
    }

    for (CDOObject object : getDetachedObjects().values())
    {
      if (object.cdoConflict())
      {
        conflicts.add(object);
      }
    }

    return conflicts;
  }

  /**
   * @since 2.0
   */
  public void resolveConflicts(CDOConflictResolver... resolvers)
  {
    Set<CDOObject> conflicts = getConflicts();
    handleConflicts(conflicts, resolvers);
  }

  public void handleConflicts(Set<CDOObject> conflicts)
  {
    handleConflicts(conflicts, options().getConflictResolvers());
  }

  private void handleConflicts(Set<CDOObject> conflicts, CDOConflictResolver[] resolvers)
  {
    if (resolvers.length == 0)
    {
      return;
    }

    // Remember original state to be able to restore it after an exception
    List<CDOState> states = new ArrayList<CDOState>(conflicts.size());
    List<CDORevision> revisions = new ArrayList<CDORevision>(conflicts.size());
    for (CDOObject conflict : conflicts)
    {
      states.add(conflict.cdoState());
      revisions.add(conflict.cdoRevision());
    }

    int resolved = 0;

    try
    {
      Set<CDOObject> remaining = new HashSet<CDOObject>(conflicts);
      for (CDOConflictResolver resolver : resolvers)
      {
        resolver.resolveConflicts(Collections.unmodifiableSet(remaining));
        for (Iterator<CDOObject> it = remaining.iterator(); it.hasNext();)
        {
          CDOObject object = it.next();
          if (!object.cdoConflict())
          {
            ++resolved;
            it.remove();
          }
        }
      }
    }
    catch (Exception ex)
    {
      // Restore original state
      Iterator<CDOState> state = states.iterator();
      Iterator<CDORevision> revision = revisions.iterator();
      for (CDOObject object : conflicts)
      {
        ((InternalCDOObject)object).cdoInternalSetState(state.next());
        ((InternalCDOObject)object).cdoInternalSetRevision(revision.next());
      }

      throw WrappedException.wrap(ex);
    }

    conflict -= resolved;
  }

  /**
   * @since 2.0
   */
  public long getLastCommitTime()
  {
    return lastCommitTime;
  }

  public CDOIDTemp getNextTemporaryID()
  {
    return CDOIDUtil.createTempObject(++lastTemporaryID);
  }

  /**
   * @since 2.0
   */
  @Override
  protected CDOResourceImpl createRootResource()
  {
    return (CDOResourceImpl)getOrCreateResource(CDOResourceNode.ROOT_PATH);
  }

  public CDOResource createResource(String path)
  {
    checkActive();
    URI uri = CDOURIUtil.createResourceURI(this, path);
    return (CDOResource)getResourceSet().createResource(uri);
  }

  public CDOResource getOrCreateResource(String path)
  {
    checkActive();

    try
    {
      CDOID id = getResourceNodeID(path);
      if (!CDOIDUtil.isNull(id))
      {
        return (CDOResource)getObject(id);
      }
    }
    catch (Exception ignore)
    {
      // Just create the missing resource
    }

    return createResource(path);
  }

  /**
   * @since 2.0
   */
  @Override
  public void attachResource(CDOResourceImpl resource)
  {
    if (resource.isExisting())
    {
      super.attachResource(resource);
    }
    else
    {
      // ResourceSet.createResource(uri) was called!!
      attachNewResource(resource);
    }
  }

  private void attachNewResource(CDOResourceImpl resource)
  {
    URI uri = resource.getURI();
    List<String> names = CDOURIUtil.analyzePath(uri);
    String resourceName = names.isEmpty() ? null : names.remove(names.size() - 1);

    CDOResourceFolder folder = getOrCreateResourceFolder(names);
    attachNewResourceNode(folder, resourceName, resource);
  }

  /**
   * @return never <code>null</code>;
   * @since 2.0
   */
  public CDOResourceFolder getOrCreateResourceFolder(List<String> names)
  {
    CDOResourceFolder folder = null;
    for (String name : names)
    {
      CDOResourceNode node;

      try
      {
        CDOID folderID = folder == null ? null : folder.cdoID();
        node = getResourceNode(folderID, name);
      }
      catch (CDOException ex)
      {
        node = EresourceFactory.eINSTANCE.createCDOResourceFolder();
        attachNewResourceNode(folder, name, node);
      }

      if (node instanceof CDOResourceFolder)
      {
        folder = (CDOResourceFolder)node;
      }
      else
      {
        throw new CDOException(MessageFormat.format(Messages.getString("CDOTransactionImpl.0"), node)); //$NON-NLS-1$
      }
    }

    return folder;
  }

  private void attachNewResourceNode(CDOResourceFolder folder, String name, CDOResourceNode newNode)
  {
    CDOResourceNodeImpl node = (CDOResourceNodeImpl)newNode;
    node.basicSetName(name, false);
    if (folder == null)
    {
      if (node.isRoot())
      {
        CDOStateMachine.INSTANCE.attach(node, this);
      }
      else
      {
        getRootResource().getContents().add(node);
      }
    }
    else
    {
      node.basicSetFolder(folder, false);
    }
  }

  /**
   * @since 2.0
   */
  public void detach(CDOResourceImpl cdoResource)
  {
    CDOStateMachine.INSTANCE.detach(cdoResource);
    fireEvent(new ResourcesEvent(cdoResource.getPath(), ResourcesEvent.Kind.REMOVED));
  }

  /**
   * @since 2.0
   */
  public CDOSavepointImpl getLastSavepoint()
  {
    checkActive();
    return lastSavepoint;
  }

  /**
   * @since 2.0
   */
  public CDOTransactionStrategy getTransactionStrategy()
  {
    if (transactionStrategy == null)
    {
      transactionStrategy = CDOTransactionStrategy.DEFAULT;
      transactionStrategy.setTarget(this);
    }

    return transactionStrategy;
  }

  /**
   * @since 2.0
   */
  public void setTransactionStrategy(CDOTransactionStrategy transactionStrategy)
  {
    if (this.transactionStrategy != null)
    {
      this.transactionStrategy.unsetTarget(this);
    }

    this.transactionStrategy = transactionStrategy;
    if (this.transactionStrategy != null)
    {
      this.transactionStrategy.setTarget(this);
    }
  }

  /**
   * @since 2.0
   */
  @Override
  protected CDOID getRootOrTopLevelResourceNodeID(String name)
  {
    if (dirty)
    {
      CDOResourceNode node = getRootResourceNode(name, getDirtyObjects().values());
      if (node != null)
      {
        return node.cdoID();
      }

      node = getRootResourceNode(name, getNewObjects().values());
      if (node != null)
      {
        return node.cdoID();
      }

      node = getRootResourceNode(name, getNewResources().values());
      if (node != null)
      {
        return node.cdoID();
      }
    }

    CDOID id = super.getRootOrTopLevelResourceNodeID(name);
    if (getLastSavepoint().getAllDetachedObjects().containsKey(id) || getDirtyObjects().containsKey(id))
    {
      throw new CDOException(MessageFormat.format(Messages.getString("CDOTransactionImpl.1"), name)); //$NON-NLS-1$
    }

    return id;
  }

  private CDOResourceNode getRootResourceNode(String name, Collection<? extends CDOObject> objects)
  {
    for (CDOObject object : objects)
    {
      if (object instanceof CDOResourceNode)
      {
        CDOResourceNode node = (CDOResourceNode)object;
        if (node.getFolder() == null && ObjectUtil.equals(name, node.getName()))
        {
          return node;
        }
      }
    }

    return null;
  }

  /**
   * @since 2.0
   */
  @Override
  public InternalCDOObject getObject(CDOID id, boolean loadOnDemand)
  {
    checkActive();
    if (CDOIDUtil.isNull(id))
    {
      return null;
    }

    if (id.isTemporary() && isDetached(id))
    {
      FSMUtil.validate(id, null);
    }

    return super.getObject(id, loadOnDemand);
  }

  private boolean isDetached(CDOID id)
  {
    return lastSavepoint.getSharedDetachedObjects().contains(id);
  }

  /**
   * @since 2.0
   */
  public InternalCDOCommitContext createCommitContext()
  {
    return new CDOCommitContextImpl();
  }

  /**
   * @since 2.0
   */
  public void commit(IProgressMonitor progressMonitor) throws TransactionException
  {
    checkActive();
    if (hasConflict())
    {
      throw new TransactionException(Messages.getString("CDOTransactionImpl.2")); //$NON-NLS-1$
    }

    if (progressMonitor == null)
    {
      progressMonitor = new NullProgressMonitor();
    }

    try
    {
      getTransactionStrategy().commit(this, progressMonitor);
    }
    catch (TransactionException ex)
    {
      throw ex;
    }
    catch (Exception ex)
    {
      throw new TransactionException(ex);
    }
  }

  public void commit() throws TransactionException
  {
    commit(null);
  }

  /**
   * @since 2.0
   */
  public void rollback()
  {
    checkActive();
    rollback(firstSavepoint);
    cleanUp();
  }

  private void removeObjects(Collection<? extends CDOObject> objects)
  {
    if (!objects.isEmpty())
    {
      for (CDOObject object : objects)
      {
        ((InternalCDOObject)object).cdoInternalSetState(CDOState.TRANSIENT);
        removeObject(object.cdoID());

        if (object instanceof CDOResource)
        {
          getResourceSet().getResources().remove(object);
        }

        ((InternalCDOObject)object).cdoInternalSetID(null);
        ((InternalCDOObject)object).cdoInternalSetRevision(null);
        ((InternalCDOObject)object).cdoInternalSetView(null);
      }
    }
  }

  private Set<CDOID> rollbackCompletely(CDOSavepoint savepoint)
  {
    Set<CDOID> idsOfNewObjectWithDeltas = new HashSet<CDOID>();

    // Start from the last savepoint and come back up to the active
    for (CDOSavepointImpl itrSavepoint = lastSavepoint; itrSavepoint != null; itrSavepoint = itrSavepoint
        .getPreviousSavepoint())
    {
      // Rollback new objects created after the save point
      removeObjects(itrSavepoint.getNewResources().values());
      removeObjects(itrSavepoint.getNewObjects().values());

      Map<CDOID, CDORevisionDelta> revisionDeltas = itrSavepoint.getRevisionDeltas();
      if (!revisionDeltas.isEmpty())
      {
        for (CDORevisionDelta dirtyObject : revisionDeltas.values())
        {
          if (dirtyObject.getID().isTemporary())
          {
            idsOfNewObjectWithDeltas.add(dirtyObject.getID());
          }
        }
      }

      // Rollback all persisted objects
      Map<CDOID, CDOObject> detachedObjects = itrSavepoint.getDetachedObjects();
      if (!detachedObjects.isEmpty())
      {
        for (Entry<CDOID, CDOObject> entryDirty : detachedObjects.entrySet())
        {
          if (entryDirty.getKey().isTemporary())
          {
            idsOfNewObjectWithDeltas.add(entryDirty.getKey());
          }
          else
          {
            InternalCDOObject internalDirtyObject = (InternalCDOObject)entryDirty.getValue();
            cleanObject(internalDirtyObject, getRevision(entryDirty.getKey(), true));
          }
        }
      }

      for (Entry<CDOID, CDOObject> entryDirtyObject : itrSavepoint.getDirtyObjects().entrySet())
      {
        // Rollback all persisted objects
        if (!entryDirtyObject.getKey().isTemporary())
        {
          InternalCDOObject internalDirtyObject = (InternalCDOObject)entryDirtyObject.getValue();
          CDOStateMachine.INSTANCE.rollback(internalDirtyObject);
        }
      }

      if (savepoint == itrSavepoint)
      {
        break;
      }
    }

    return idsOfNewObjectWithDeltas;
  }

  private void loadSavepoint(CDOSavepoint savepoint, Set<CDOID> idsOfNewObjectWithDeltas)
  {
    lastSavepoint.recalculateSharedDetachedObjects();

    Map<CDOID, CDOObject> dirtyObjects = getDirtyObjects();
    Map<CDOID, CDOObject> newObjMaps = getNewObjects();
    Map<CDOID, CDOResource> newResources = getNewResources();
    Map<CDOID, CDORevision> newBaseRevision = getBaseNewObjects();
    Map<CDOID, CDOObject> detachedObjects = getDetachedObjects();

    // Reload the objects (NEW) with their base.
    for (CDOID id : idsOfNewObjectWithDeltas)
    {
      if (detachedObjects.containsKey(id))
      {
        continue;
      }

      InternalCDOObject object = (InternalCDOObject)newObjMaps.get(id);
      if (object == null)
      {
        object = (InternalCDOObject)newResources.get(id);
      }

      CDORevision revision = newBaseRevision.get(id);
      if (revision != null)
      {
        object.cdoInternalSetRevision(revision.copy());
        object.cdoInternalSetView(this);
        object.cdoInternalSetID(revision.getID());
        object.cdoInternalSetState(CDOState.NEW);

        // Load the object from revision to EObject
        object.cdoInternalPostLoad();
      }
    }

    // We need to register back new objects that are not removed anymore there.
    for (Entry<CDOID, CDOObject> entryNewObject : newObjMaps.entrySet())
    {
      InternalCDOObject object = (InternalCDOObject)entryNewObject.getValue();

      // Go back to the previous state
      cleanObject(object, object.cdoRevision());
      object.cdoInternalSetState(CDOState.NEW);
    }

    for (Entry<CDOID, CDOObject> entryDirtyObject : dirtyObjects.entrySet())
    {
      if (detachedObjects.containsKey(entryDirtyObject.getKey()))
      {
        continue;
      }

      // Rollback every persisted objects
      InternalCDOObject internalDirtyObject = (InternalCDOObject)entryDirtyObject.getValue();
      cleanObject(internalDirtyObject, getRevision(entryDirtyObject.getKey(), true));
    }

    for (CDOSavepointImpl itrSavepoint = firstSavepoint; itrSavepoint != savepoint; itrSavepoint = itrSavepoint
        .getNextSavepoint())
    {
      CDOObjectMerger merger = new CDOObjectMerger();
      for (CDORevisionDelta delta : itrSavepoint.getRevisionDeltas().values())
      {
        if (delta.getID().isTemporary() && !idsOfNewObjectWithDeltas.contains(delta.getID())
            || detachedObjects.containsKey(delta.getID()))
        {
          continue;
        }

        Map<CDOID, CDOObject> map = delta.getID().isTemporary() ? newObjMaps : dirtyObjects;
        InternalCDOObject object = (InternalCDOObject)map.get(delta.getID());
        if (object == null)
        {
          object = (InternalCDOObject)newResources.get(delta.getID());
        }

        // Change state of the objects
        merger.merge(object, delta);

        // Load the object from revision to EObject
        object.cdoInternalPostLoad();
      }
    }

    dirty = ((CDOSavepointImpl)savepoint).isDirty();
  }

  /**
   * @since 2.0
   */
  public void detachObject(InternalCDOObject object)
  {
    for (CDOTransactionHandler handler : getHandlers())
    {
      handler.detachingObject(this, object);
    }

    // deregister object
    if (object.cdoState() == CDOState.NEW)
    {
      Map<CDOID, ? extends CDOObject> map = object instanceof CDOResource ? getLastSavepoint().getNewResources()
          : getLastSavepoint().getNewObjects();

      // Determine if we added object
      if (map.containsKey(object.cdoID()))
      {
        // deregister object
        deregisterObject(object);
        map.remove(object.cdoID());
      }
      else
      {
        getLastSavepoint().getDetachedObjects().put(object.cdoID(), object);
      }
    }
    else
    {
      getLastSavepoint().getDetachedObjects().put(object.cdoID(), object);
    }

    if (!dirty)
    {
      dirty = true;
      fireEvent(new StartedEvent());
    }
  }

  /**
   * @since 2.0
   */
  public void rollback(CDOSavepoint savepoint)
  {
    checkActive();
    getTransactionStrategy().rollback(this, savepoint);
  }

  /**
   * @since 2.0
   */
  public void handleRollback(CDOSavepoint savepoint)
  {
    if (savepoint == null)
    {
      throw new IllegalArgumentException(Messages.getString("CDOTransactionImpl.3")); //$NON-NLS-1$
    }

    if (savepoint.getUserTransaction() != this)
    {
      throw new IllegalArgumentException(MessageFormat.format(Messages.getString("CDOTransactionImpl.4"), savepoint)); //$NON-NLS-1$
    }

    if (TRACER.isEnabled())
    {
      TRACER.trace("handleRollback()"); //$NON-NLS-1$
    }

    try
    {
      if (!savepoint.isValid())
      {
        throw new IllegalArgumentException(MessageFormat.format(Messages.getString("CDOTransactionImpl.6"), savepoint)); //$NON-NLS-1$
      }

      // Use the state lock since rollback mechanism is playing with EObject and CDORevisions. We do not want to
      // receives notifications during that process! neither the user should callload any objects.
      ReentrantLock viewLock = getStateLock();
      viewLock.lock();

      try
      {
        // Rollback objects
        Set<CDOID> idsOfNewObjectWithDeltas = rollbackCompletely(savepoint);

        lastSavepoint = (CDOSavepointImpl)savepoint;
        // Make savepoint active. Erase savepoint that could have be after
        lastSavepoint.setNextSavepoint(null);
        lastSavepoint.clear();

        // Load from first savepoint up to current savepoint
        loadSavepoint(lastSavepoint, idsOfNewObjectWithDeltas);

        if (lastSavepoint == firstSavepoint && options().isAutoReleaseLocksEnabled())
        {
          // Unlock all objects
          unlockObjects(null, null);
        }
      }
      finally
      {
        viewLock.unlock();
      }

      Map<CDOIDTemp, CDOID> idMappings = Collections.emptyMap();
      fireEvent(new FinishedEvent(CDOTransactionFinishedEvent.Type.ROLLED_BACK, idMappings));
      for (CDOTransactionHandler handler : getHandlers())
      {
        try
        {
          handler.rolledBackTransaction(this);
        }
        catch (RuntimeException ex)
        {
          OM.LOG.error(ex);
        }
      }
    }
    catch (RuntimeException ex)
    {
      throw ex;
    }
    catch (Exception ex)
    {
      throw new TransactionException(ex);
    }
  }

  /**
   * @since 2.0
   */
  public CDOSavepoint handleSetSavepoint()
  {
    // Take a copy of all new objects for the current save point
    addToBase(lastSavepoint.getNewObjects());
    addToBase(lastSavepoint.getNewResources());

    lastSavepoint = new CDOSavepointImpl(this, lastSavepoint);
    return lastSavepoint;
  }

  /**
   * @since 2.0
   */
  public CDOSavepoint setSavepoint()
  {
    checkActive();
    return getTransactionStrategy().setSavepoint(this);
  }

  private void addToBase(Map<CDOID, ? extends CDOObject> objects)
  {
    for (CDOObject object : objects.values())
    {
      // Load instance to revision
      ((InternalCDOObject)object).cdoInternalPreCommit();
      lastSavepoint.getBaseNewObjects().put(object.cdoID(), object.cdoRevision().copy());
    }
  }

  @Override
  public String toString()
  {
    return MessageFormat.format("CDOTransaction({0})", getViewID()); //$NON-NLS-1$
  }

  public void registerNew(InternalCDOObject object)
  {
    if (TRACER.isEnabled())
    {
      TRACER.format("Registering new object {0}", object); //$NON-NLS-1$
    }

    registerNewPackage(object.eClass().getEPackage());

    for (CDOTransactionHandler handler : getHandlers())
    {
      handler.attachingObject(this, object);
    }

    if (object instanceof CDOResourceImpl)
    {
      registerNew(lastSavepoint.getNewResources(), object);
    }
    else
    {
      registerNew(lastSavepoint.getNewObjects(), object);
    }
  }

  private void registerNewPackage(EPackage ePackage)
  {
    CDOPackageRegistry packageRegistry = getSession().getPackageRegistry();
    if (!packageRegistry.containsKey(ePackage.getNsURI()))
    {
      packageRegistry.putEPackage(ePackage);
    }
  }

  /**
   * Receives notification for new and dirty objects
   */
  public void registerFeatureDelta(InternalCDOObject object, CDOFeatureDelta featureDelta)
  {
    boolean needToSaveFeatureDelta = true;
    if (object.cdoState() == CDOState.NEW)
    {
      // Register Delta for new objects only if objectA doesn't belong to this savepoint
      if (getLastSavepoint().getPreviousSavepoint() == null || featureDelta == null)
      {
        needToSaveFeatureDelta = false;
      }
      else
      {
        Map<CDOID, ? extends CDOObject> map = object instanceof CDOResource ? getLastSavepoint().getNewResources()
            : getLastSavepoint().getNewObjects();
        needToSaveFeatureDelta = !map.containsKey(object.cdoID());
      }
    }

    if (needToSaveFeatureDelta)
    {
      CDORevisionDelta revisionDelta = lastSavepoint.getRevisionDeltas().get(object.cdoID());
      if (revisionDelta == null)
      {
        revisionDelta = CDORevisionDeltaUtil.create(object.cdoRevision());
        lastSavepoint.getRevisionDeltas().put(object.cdoID(), revisionDelta);
      }

      ((InternalCDORevisionDelta)revisionDelta).addFeatureDelta(featureDelta);
    }

    for (CDOTransactionHandler handler : getHandlers())
    {
      handler.modifyingObject(this, object, featureDelta);
    }
  }

  public void registerRevisionDelta(CDORevisionDelta revisionDelta)
  {
    lastSavepoint.getRevisionDeltas().putIfAbsent(revisionDelta.getID(), revisionDelta);
  }

  public void registerDirty(InternalCDOObject object, CDOFeatureDelta featureDelta)
  {
    if (TRACER.isEnabled())
    {
      TRACER.format("Registering dirty object {0}", object); //$NON-NLS-1$
    }

    if (featureDelta != null)
    {
      registerFeatureDelta(object, featureDelta);
    }

    registerNew(lastSavepoint.getDirtyObjects(), object);
  }

  /**
   * TODO Simon: Should this method go to CDOSavePointImpl?
   */
  @SuppressWarnings("unchecked")
  private void registerNew(Map map, InternalCDOObject object)
  {
    Object old = map.put(object.cdoID(), object);
    if (old != null)
    {
      throw new ImplementationError(MessageFormat.format(Messages.getString("CDOTransactionImpl.10"), object)); //$NON-NLS-1$
    }

    if (!dirty)
    {
      dirty = true;
      fireEvent(new StartedEvent());
    }
  }

  private List<CDOPackageUnit> analyzeNewPackages()
  {
    CDOPackageRegistry packageRegistry = getSession().getPackageRegistry();
    Set<EPackage> usedPackages = new HashSet<EPackage>();
    Set<EPackage> usedNewPackages = new HashSet<EPackage>();
    for (CDOObject object : getNewObjects().values())
    {
      EPackage ePackage = object.eClass().getEPackage();
      if (usedPackages.add(ePackage))
      {
        EPackage topLevelPackage = EMFUtil.getTopLevelPackage(ePackage);
        if (ePackage == topLevelPackage || usedPackages.add(topLevelPackage))
        {
          if (!CDOModelUtil.isSystemPackage(topLevelPackage))
          {
            CDOPackageUnit packageUnit = packageRegistry.getPackageUnit(topLevelPackage);
            if (packageUnit.getState() == CDOPackageUnit.State.NEW)
            {
              usedNewPackages.add(topLevelPackage);
            }
          }
        }
      }
    }

    if (usedNewPackages.size() > 0)
    {
      Set<CDOPackageUnit> result = new HashSet<CDOPackageUnit>();
      for (EPackage usedNewPackage : analyzeNewPackages(usedNewPackages, packageRegistry))
      {
        CDOPackageUnit packageUnit = packageRegistry.getPackageUnit(usedNewPackage);
        result.add(packageUnit);
      }

      return new ArrayList<CDOPackageUnit>(result);
    }

    return Collections.emptyList();
  }

  private static List<EPackage> analyzeNewPackages(Collection<EPackage> usedTopLevelPackages,
      CDOPackageRegistry packageRegistry)
  {
    // Determine which of the corresdonding EPackages are new
    List<EPackage> newPackages = new ArrayList<EPackage>();

    IPackageClosure closure = new CompletePackageClosure();
    usedTopLevelPackages = closure.calculate(usedTopLevelPackages);

    for (EPackage usedPackage : usedTopLevelPackages)
    {
      if (!CDOModelUtil.isSystemPackage(usedPackage))
      {
        CDOPackageUnit packageUnit = packageRegistry.getPackageUnit(usedPackage);
        if (packageUnit == null)
        {
          throw new CDOException(MessageFormat.format(Messages.getString("CDOTransactionImpl.11"), usedPackage)); //$NON-NLS-1$
        }

        if (packageUnit.getState() == CDOPackageUnit.State.NEW)
        {
          newPackages.add(usedPackage);
        }
      }
    }

    return newPackages;
  }

  private void cleanUp()
  {
    lastSavepoint = firstSavepoint;
    firstSavepoint.clear();
    firstSavepoint.setNextSavepoint(null);
    firstSavepoint.getSharedDetachedObjects().clear();
    dirty = false;
    conflict = 0;
    lastTemporaryID = 0;
  }

  public Map<CDOID, CDOObject> getDirtyObjects()
  {
    checkActive();
    return lastSavepoint.getAllDirtyObjects();
  }

  public Map<CDOID, CDOObject> getNewObjects()
  {
    checkActive();
    return lastSavepoint.getAllNewObjects();
  }

  public Map<CDOID, CDOResource> getNewResources()
  {
    checkActive();
    return lastSavepoint.getAllNewResources();
  }

  /**
   * @since 2.0
   */
  public Map<CDOID, CDORevision> getBaseNewObjects()
  {
    checkActive();
    return lastSavepoint.getAllBaseNewObjects();
  }

  public Map<CDOID, CDORevisionDelta> getRevisionDeltas()
  {
    checkActive();
    return lastSavepoint.getAllRevisionDeltas();
  }

  /**
   * @since 2.0
   */
  public Map<CDOID, CDOObject> getDetachedObjects()
  {
    checkActive();
    return lastSavepoint.getAllDetachedObjects();
  }

  /**
   * @since 2.0
   */
  @Override
  protected void doDeactivate() throws Exception
  {
    options().disposeConflictResolvers();
    lastSavepoint = null;
    firstSavepoint = null;
    transactionStrategy = null;
    super.doDeactivate();
  }

  /**
   * @author Simon McDuff
   */
  private class CDOCommitContextImpl implements InternalCDOCommitContext
  {
    private Map<CDOID, CDOResource> newResources;

    private Map<CDOID, CDOObject> newObjects;

    private Map<CDOID, CDOObject> dirtyObjects;

    private Map<CDOID, CDORevisionDelta> revisionDeltas;

    private Map<CDOID, CDOObject> detachedObjects;

    private List<CDOPackageUnit> newPackageUnits;

    public CDOCommitContextImpl()
    {
      CDOTransactionImpl transaction = getTransaction();
      newResources = transaction.getNewResources();
      newObjects = transaction.getNewObjects();
      dirtyObjects = transaction.getDirtyObjects();
      detachedObjects = transaction.getDetachedObjects();
      revisionDeltas = transaction.getRevisionDeltas();
      newPackageUnits = transaction.analyzeNewPackages();
    }

    public CDOTransactionImpl getTransaction()
    {
      return CDOTransactionImpl.this;
    }

    public Map<CDOID, CDOObject> getDirtyObjects()
    {
      return dirtyObjects;
    }

    public Map<CDOID, CDOObject> getNewObjects()
    {
      return newObjects;
    }

    public List<CDOPackageUnit> getNewPackageUnits()
    {
      return newPackageUnits;
    }

    public Map<CDOID, CDOResource> getNewResources()
    {
      return newResources;
    }

    public Map<CDOID, CDOObject> getDetachedObjects()
    {
      return detachedObjects;
    }

    public Map<CDOID, CDORevisionDelta> getRevisionDeltas()
    {
      return revisionDeltas;
    }

    public void preCommit()
    {
      if (isDirty())
      {
        if (TRACER.isEnabled())
        {
          TRACER.trace("commit()"); //$NON-NLS-1$
        }

        for (CDOTransactionHandler handler : getHandlers())
        {
          handler.committingTransaction(getTransaction(), this);
        }

        try
        {
          preCommit(getNewResources());
          preCommit(getNewObjects());
          preCommit(getDirtyObjects());
        }
        catch (RuntimeException ex)
        {
          throw ex;
        }
        catch (Exception ex)
        {
          throw new TransactionException(ex);
        }
      }
    }

    public void postCommit(CommitTransactionResult result)
    {
      if (isDirty())
      {
        try
        {
          Collection<CDORevisionDelta> deltas = getRevisionDeltas().values();

          postCommit(getNewResources(), result);
          postCommit(getNewObjects(), result);
          postCommit(getDirtyObjects(), result);
          for (Entry<CDOID, CDOObject> entry : getDetachedObjects().entrySet())
          {
            removeObject(entry.getKey());
          }

          InternalCDOSession session = getSession();
          for (CDOPackageUnit newPackageUnit : newPackageUnits)
          {
            ((InternalCDOPackageUnit)newPackageUnit).setState(CDOPackageUnit.State.LOADED);
          }

          long timeStamp = result.getTimeStamp();

          Map<CDOID, CDOObject> dirtyObjects = getDirtyObjects();
          Set<CDOIDAndVersion> dirtyIDs = new HashSet<CDOIDAndVersion>();
          for (CDOObject dirtyObject : dirtyObjects.values())
          {
            CDORevision revision = dirtyObject.cdoRevision();
            CDOIDAndVersion dirtyID = CDOIDUtil.createIDAndVersion(revision.getID(), revision.getVersion() - 1);
            dirtyIDs.add(dirtyID);
          }

          if (!dirtyIDs.isEmpty() || !getDetachedObjects().isEmpty())
          {
            Set<CDOID> detachedIDs = new HashSet<CDOID>(getDetachedObjects().keySet());
            Collection<CDORevisionDelta> deltasCopy = new ArrayList<CDORevisionDelta>(deltas);

            // Adjust references in the deltas. Could be used in ChangeSubscription from others CDOView
            for (CDORevisionDelta dirtyObjectDelta : deltasCopy)
            {
              ((InternalCDORevisionDelta)dirtyObjectDelta).adjustReferences(result.getReferenceAdjuster());
            }

            session.handleCommitNotification(timeStamp, newPackageUnits, dirtyIDs, detachedIDs, deltasCopy,
                getTransaction());
          }

          lastCommitTime = timeStamp;
          for (CDOTransactionHandler handler : getHandlers())
          {
            handler.committedTransaction(getTransaction(), this);
          }

          getChangeSubscriptionManager().committedTransaction(getTransaction(), this);
          getAdapterManager().committedTransaction(getTransaction(), this);

          cleanUp();
          Map<CDOIDTemp, CDOID> idMappings = result.getIDMappings();
          fireEvent(new FinishedEvent(CDOTransactionFinishedEvent.Type.COMMITTED, idMappings));
        }
        catch (RuntimeException ex)
        {
          throw ex;
        }
        catch (Exception ex)
        {
          throw new TransactionException(ex);
        }
      }
      else
      {
        // Removes locks even if no one touch the transaction
        if (options().isAutoReleaseLocksEnabled())
        {
          unlockObjects(null, null);
        }
      }
    }

    @SuppressWarnings("unchecked")
    private void preCommit(Map objects)
    {
      if (!objects.isEmpty())
      {
        for (Object object : objects.values())
        {
          ((InternalCDOObject)object).cdoInternalPreCommit();
        }
      }
    }

    @SuppressWarnings("unchecked")
    private void postCommit(Map objects, CommitTransactionResult result)
    {
      if (!objects.isEmpty())
      {
        for (Object object : objects.values())
        {
          CDOStateMachine.INSTANCE.commit((InternalCDOObject)object, result);
        }
      }
    }
  }

  /**
   * @author Eike Stepper
   */
  private final class StartedEvent extends Event implements CDOTransactionStartedEvent
  {
    private static final long serialVersionUID = 1L;

    private StartedEvent()
    {
    }

    @Override
    public String toString()
    {
      return MessageFormat.format("CDOTransactionStartedEvent[source={0}]", getSource()); //$NON-NLS-1$
    }
  }

  /**
   * @author Eike Stepper
   */
  private final class FinishedEvent extends Event implements CDOTransactionFinishedEvent
  {
    private static final long serialVersionUID = 1L;

    private Type type;

    private Map<CDOIDTemp, CDOID> idMappings;

    private FinishedEvent(Type type, Map<CDOIDTemp, CDOID> idMappings)
    {
      this.type = type;
      this.idMappings = idMappings;
    }

    public Type getType()
    {
      return type;
    }

    public Map<CDOIDTemp, CDOID> getIDMappings()
    {
      return idMappings;
    }

    @Override
    public String toString()
    {
      return MessageFormat.format("CDOTransactionFinishedEvent[source={0}, type={1}, idMappings={2}]", getSource(), //$NON-NLS-1$
          getType(), idMappings == null ? 0 : idMappings.size());
    }
  }

  /**
   * @author Eike Stepper
   */
  private final class ConflictEvent extends Event implements CDOTransactionConflictEvent
  {
    private static final long serialVersionUID = 1L;

    private InternalCDOObject conflictingObject;

    private boolean firstConflict;

    public ConflictEvent(InternalCDOObject conflictingObject, boolean firstConflict)
    {
      this.conflictingObject = conflictingObject;
      this.firstConflict = firstConflict;
    }

    public InternalCDOObject getConflictingObject()
    {
      return conflictingObject;
    }

    public boolean isFirstConflict()
    {
      return firstConflict;
    }

    @Override
    public String toString()
    {
      return MessageFormat.format("CDOTransactionConflictEvent[source={0}, conflictingObject={1}, firstConflict={2}]", //$NON-NLS-1$
          getSource(), getConflictingObject(), isFirstConflict());
    }
  }

  /**
   * @author Eike Stepper
   */
  private final class ResourcesEvent extends Event implements CDOViewResourcesEvent
  {
    private static final long serialVersionUID = 1L;

    private String resourcePath;

    private Kind kind;

    public ResourcesEvent(String resourcePath, Kind kind)
    {
      this.resourcePath = resourcePath;
      this.kind = kind;
    }

    public String getResourcePath()
    {
      return resourcePath;
    }

    public Kind getKind()
    {
      return kind;
    }

    @Override
    public String toString()
    {
      return MessageFormat.format("CDOViewResourcesEvent[source={0}, {1}={2}]", getSource(), resourcePath, kind); //$NON-NLS-1$
    }
  }

  /**
   * @author Eike Stepper
   * @since 2.0
   */
  protected final class OptionsImpl extends CDOViewImpl.OptionsImpl implements CDOTransaction.Options
  {
    private List<CDOConflictResolver> conflictResolvers = new ArrayList<CDOConflictResolver>();

    private boolean autoReleaseLocksEnabled = true;

    public OptionsImpl()
    {
    }

    public CDOConflictResolver[] getConflictResolvers()
    {
      synchronized (conflictResolvers)
      {
        return conflictResolvers.toArray(new CDOConflictResolver[conflictResolvers.size()]);
      }
    }

    public void setConflictResolvers(CDOConflictResolver[] resolvers)
    {
      synchronized (conflictResolvers)
      {
        for (CDOConflictResolver resolver : conflictResolvers)
        {
          resolver.setTransaction(null);
        }

        conflictResolvers.clear();
        for (CDOConflictResolver resolver : resolvers)
        {
          validateResolver(resolver);
          conflictResolvers.add(resolver);
        }
      }

      fireEvent(new ConflictResolversEventImpl());
    }

    public void addConflictResolver(CDOConflictResolver resolver)
    {
      boolean changed = false;
      synchronized (conflictResolvers)
      {
        if (!conflictResolvers.contains(resolver))
        {
          validateResolver(resolver);
          conflictResolvers.add(resolver);
          changed = true;
        }
      }

      if (changed)
      {
        fireEvent(new ConflictResolversEventImpl());
      }
    }

    public void removeConflictResolver(CDOConflictResolver resolver)
    {
      boolean changed = false;
      synchronized (conflictResolvers)
      {
        changed = conflictResolvers.remove(resolver);
      }

      if (changed)
      {
        resolver.setTransaction(null);
        fireEvent(new ConflictResolversEventImpl());
      }
    }

    public void disposeConflictResolvers()
    {
      try
      {
        for (CDOConflictResolver resolver : options().getConflictResolvers())
        {
          try
          {
            resolver.setTransaction(null);
          }
          catch (Exception ignore)
          {
          }
        }
      }
      catch (Exception ignore)
      {
      }
    }

    private void validateResolver(CDOConflictResolver resolver)
    {
      if (resolver.getTransaction() != null)
      {
        throw new IllegalArgumentException(Messages.getString("CDOTransactionImpl.17")); //$NON-NLS-1$
      }

      resolver.setTransaction(CDOTransactionImpl.this);
    }

    public boolean isAutoReleaseLocksEnabled()
    {
      return autoReleaseLocksEnabled;
    }

    public void setAutoReleaseLocksEnabled(boolean on)
    {
      if (autoReleaseLocksEnabled != on)
      {
        autoReleaseLocksEnabled = on;
        fireEvent(new AutoReleaseLockEventImpl());
      }
    }

    /**
     * @author Eike Stepper
     */
    private final class ConflictResolversEventImpl extends OptionsEvent implements ConflictResolversEvent
    {
      private static final long serialVersionUID = 1L;

      public ConflictResolversEventImpl()
      {
        super(OptionsImpl.this);
      }
    }

    /**
     * @author Eike Stepper
     */
    private final class AutoReleaseLockEventImpl extends OptionsEvent implements AutoReleaseLockEvent
    {
      private static final long serialVersionUID = 1L;

      public AutoReleaseLockEventImpl()
      {
        super(OptionsImpl.this);
      }
    }
  }
}