/*
    * ModeShape (http://www.modeshape.org)
    * See the COPYRIGHT.txt file distributed with this work for information
    * regarding copyright ownership.  Some portions may be licensed
    * to Red Hat, Inc. under one or more contributor license agreements.
    * See the AUTHORS.txt file in the distribution for a full listing of 
    * individual contributors.
    *
    * ModeShape is free software. Unless otherwise indicated, all code in ModeShape
   * is licensed to you 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.
   * 
   * ModeShape 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.modeshape.jcr;
  
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Calendar;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.LinkedHashMap;
  import java.util.LinkedList;
  import java.util.List;
  import java.util.Map;
  import java.util.Set;
  import java.util.UUID;
  import javax.jcr.AccessDeniedException;
  import javax.jcr.InvalidItemStateException;
  import javax.jcr.ItemExistsException;
  import javax.jcr.ItemNotFoundException;
  import javax.jcr.MergeException;
  import javax.jcr.NoSuchWorkspaceException;
  import javax.jcr.NodeIterator;
  import javax.jcr.PathNotFoundException;
  import javax.jcr.Property;
  import javax.jcr.PropertyIterator;
  import javax.jcr.PropertyType;
  import javax.jcr.RepositoryException;
  import javax.jcr.UnsupportedRepositoryOperationException;
  import javax.jcr.Value;
  import javax.jcr.lock.LockException;
  import javax.jcr.nodetype.ConstraintViolationException;
  import javax.jcr.nodetype.NodeDefinition;
  import javax.jcr.nodetype.PropertyDefinition;
  import javax.jcr.version.OnParentVersionAction;
  import javax.jcr.version.Version;
  import javax.jcr.version.VersionException;
  import javax.jcr.version.VersionHistory;
  import javax.jcr.version.VersionIterator;
  import javax.jcr.version.VersionManager;
  import net.jcip.annotations.NotThreadSafe;
  import org.modeshape.common.i18n.I18n;
  import org.modeshape.common.text.Jsr283Encoder;
  import org.modeshape.common.text.TextEncoder;
  import org.modeshape.common.util.CheckArg;
  import org.modeshape.common.util.Logger;
  import org.modeshape.graph.ExecutionContext;
  import org.modeshape.graph.Graph;
  import org.modeshape.graph.Location;
  import org.modeshape.graph.Graph.Batch;
  import org.modeshape.graph.property.DateTime;
  import org.modeshape.graph.property.DateTimeFactory;
  import org.modeshape.graph.property.Name;
  import org.modeshape.graph.property.Path;
  import org.modeshape.graph.property.PropertyFactory;
  import org.modeshape.graph.property.Reference;
  import org.modeshape.graph.property.ValueFactories;
  import org.modeshape.graph.property.ValueFactory;
  import org.modeshape.graph.property.Path.Segment;
  import org.modeshape.graph.session.GraphSession.Node;
  import org.modeshape.graph.session.GraphSession.PropertyInfo;
  import org.modeshape.jcr.SessionCache.JcrNodePayload;
  import org.modeshape.jcr.SessionCache.JcrPropertyPayload;
  import org.modeshape.jcr.SessionCache.NodeEditor;
  
  /**
   * Local implementation of version management code, comparable to an implementation of the JSR-283 {@code VersionManager}
   * interface. Valid instances of this class can be obtained by calling {@link JcrWorkspace#versionManager()}.
   */
  final class JcrVersionManager implements VersionManager {
  
      private static final Logger LOGGER = Logger.getLogger(JcrVersionManager.class);
  
      private static final TextEncoder NODE_ENCODER = new Jsr283Encoder();
  
      static final Object[] EMPTY_OBJECT_ARRAY = new Object[0];
  
     /**
      * Property names from nt:frozenNode that should never be copied directly to a node when the frozen node is restored.
      */
     static final Set<Name> IGNORED_PROP_NAMES_FOR_RESTORE = Collections.unmodifiableSet(new HashSet<Name>(
                                                                                                           Arrays.asList(new Name[] {
                                                                                                               JcrLexicon.FROZEN_PRIMARY_TYPE,
                                                                                                               JcrLexicon.FROZEN_MIXIN_TYPES,
                                                                                                               JcrLexicon.FROZEN_UUID,
                                                                                                               JcrLexicon.PRIMARY_TYPE,
                                                                                                               JcrLexicon.MIXIN_TYPES,
                                                                                                               JcrLexicon.UUID})));
 
     private final JcrSession session;
 
     public JcrVersionManager( JcrSession session ) {
         super();
         this.session = session;
     }
 
     ExecutionContext context() {
         return session.getExecutionContext();
     }
 
     private ValueFactories factories() {
         return context().getValueFactories();
     }
 
     UUID uuid( Object ob ) {
         return factories().getUuidFactory().create(ob);
     }
 
     Name name( String s ) {
         return factories().getNameFactory().create(s);
     }
 
     Name name( Object ob ) {
         return factories().getNameFactory().create(ob);
     }
 
     final Path path( Path root,
                      Name child ) {
         return factories().getPathFactory().create(root, child);
     }
 
     Path path( Path root,
                Path.Segment childSegment ) {
         return factories().getPathFactory().create(root, childSegment);
     }
 
     private Path absolutePath( Name... absolutePathSegments ) {
         return factories().getPathFactory().createAbsolutePath(absolutePathSegments);
     }
 
     DateTime dateTime( Calendar cal ) {
         return factories().getDateFactory().create(cal);
     }
 
     private PropertyFactory propertyFactory() {
         return context().getPropertyFactory();
     }
 
     SessionCache cache() {
         return session.cache();
     }
 
     private JcrRepository repository() {
         return session.repository();
     }
 
     JcrSession session() {
         return session;
     }
 
     JcrWorkspace workspace() {
         return session.workspace();
     }
 
     /**
      * @param uuid the value of the {@code jcr:uuid} property (as a UUID) for the node for which the version history should be
      *        returned
      * @return the path to the version history node that corresponds to the node with the given UUID. This does not guarantee that
      *         a node exists at the returned path. In fact, if the node with the given UUID is not versionable (i.e., {@code
      *         node.getUUID().equals(uuid.toString()) && !node.isNodeType("mix:versionable")}), there will most likely not be a
      *         node at the path returned by this method.
      */
     Path versionHistoryPathFor( UUID uuid ) {
         return absolutePath(JcrLexicon.SYSTEM, JcrLexicon.VERSION_STORAGE, name(uuid.toString()));
     }
 
     /**
      * Returns the version history (if one exists) for the given node.
      * 
      * @param node the node for which the history should be returned
      * @return the version history for the node
      * @throws ItemNotFoundException if there is no version history for the given UUID
      * @throws RepositoryException if any other error occurs accessing the repository
      * @see AbstractJcrNode#getVersionHistory()
      */
     JcrVersionHistoryNode getVersionHistory( AbstractJcrNode node ) throws RepositoryException {
         session.checkLive();
         checkVersionable(node);
 
         Location historyLocation = Location.create(versionHistoryPathFor(node.uuid()));
         try {
             return (JcrVersionHistoryNode)cache().findJcrNode(historyLocation);
         } catch (ItemNotFoundException infe) {
             initializeVersionHistoryFor(node);
 
             // This will throw an ItemNotFoundException if the history node still doesn't exist
             JcrVersionHistoryNode historyNode = (JcrVersionHistoryNode)cache().findJcrNode(historyLocation);
 
             LOGGER.warn(JcrI18n.repairedVersionStorage, historyLocation);
 
             return historyNode;
         }
     }
 
     /**
      * Returns the node definition for the given node
      * 
      * @param node the node for which the definition should be returned
      * @return the active node definition for the given node
      * @throws RepositoryException if an error occurs accessing the repository
      * @see JcrNodeTypeManager#getNodeDefinition(NodeDefinitionId)
      */
     JcrNodeDefinition nodeDefinitionFor( Node<JcrNodePayload, JcrPropertyPayload> node ) throws RepositoryException {
         NodeDefinitionId nodeDefnId = node.getPayload().getDefinitionId();
         return session().nodeTypeManager().getNodeDefinition(nodeDefnId);
     }
 
     /**
      * Checks in the given node, creating (and returning) a new {@link Version}.
      * 
      * @param node the node to be checked in
      * @return the {@link Version} object created as a result of this checkin
      * @throws RepositoryException if an error occurs during the checkin. See {@link javax.jcr.Node#checkin()} for a full
      *         description of the possible error conditions.
      */
     JcrVersionNode checkin( AbstractJcrNode node ) throws RepositoryException {
 
         session.checkLive();
 
         checkVersionable(node);
 
         if (node.isNew() || node.isModified()) {
             throw new InvalidItemStateException(JcrI18n.noPendingChangesAllowed.text());
         }
 
         // Check this separately since it throws a different type of exception
         if (node.isLocked() && !node.holdsLock()) {
             throw new LockException(JcrI18n.lockTokenNotHeld.text(node.getPath()));
         }
 
         if (node.getProperty(JcrLexicon.MERGE_FAILED) != null) {
             throw new VersionException(JcrI18n.pendingMergeConflicts.text(node.getPath()));
         }
 
         Property isCheckedOut = node.getProperty(JcrLexicon.IS_CHECKED_OUT);
 
         if (!isCheckedOut.getBoolean()) {
             return node.getBaseVersion();
         }
 
         Name primaryTypeName = node.getPrimaryTypeName();
         List<Name> mixinTypeNames = node.getMixinTypeNames();
 
         UUID jcrUuid = node.uuid();
         UUID versionUuid = UUID.randomUUID();
 
         AbstractJcrNode historyNode = getVersionHistory(node);
         Path historyPath = historyNode.path();
 
         Graph systemGraph = repository().createSystemGraph(context());
         Graph.Batch systemBatch = systemGraph.batch();
         DateTime now = context().getValueFactories().getDateFactory().create();
 
         Path versionPath = path(historyPath, name(NODE_ENCODER.encode(now.getString())));
         AbstractJcrProperty predecessorsProp = node.getProperty(JcrLexicon.PREDECESSORS);
 
         systemBatch.create(versionPath)
                    .with(JcrLexicon.PRIMARY_TYPE, JcrNtLexicon.VERSION)
                    .and(JcrLexicon.CREATED, now)
                    .and(JcrLexicon.UUID, versionUuid)
                    .and(predecessorsProp.property())
                    .and();
         Path frozenVersionPath = path(versionPath, JcrLexicon.FROZEN_NODE);
         systemBatch.create(frozenVersionPath)
                    .with(JcrLexicon.PRIMARY_TYPE, JcrNtLexicon.FROZEN_NODE)
                    .and(JcrLexicon.FROZEN_UUID, jcrUuid)
                    .and(JcrLexicon.FROZEN_PRIMARY_TYPE, primaryTypeName)
                    .and(JcrLexicon.FROZEN_MIXIN_TYPES, mixinTypeNames)
                    .and(versionedPropertiesFor(node))
                    .and();
         int onParentVersion = node.getDefinition().getOnParentVersion();
         for (NodeIterator childNodes = node.getNodes(); childNodes.hasNext();) {
             AbstractJcrNode childNode = (AbstractJcrNode)childNodes.nextNode();
             versionNodeAt(childNode, frozenVersionPath, systemBatch, onParentVersion);
         }
 
         PropertyFactory propFactory = propertyFactory();
 
         for (Object ob : predecessorsProp.property()) {
             UUID predUuid = uuid(ob);
 
             org.modeshape.graph.property.Property successorsProp = systemGraph.getNodeAt(predUuid)
                                                                               .getProperty(JcrLexicon.SUCCESSORS);
 
             List<Object> newSuccessors = new LinkedList<Object>();
             boolean alreadySuccessor = false;
             if (successorsProp != null) {
                 for (Object successor : successorsProp) {
                     newSuccessors.add(successor);
                     if (uuid(successor).equals(predUuid)) alreadySuccessor = true;
                 }
             }
 
             if (!alreadySuccessor) {
                 newSuccessors.add(versionUuid);
 
                 org.modeshape.graph.property.Property newSuccessorsProp = propFactory.create(JcrLexicon.SUCCESSORS,
                                                                                              newSuccessors.toArray());
                 systemBatch.set(newSuccessorsProp).on(predUuid).and();
             }
         }
 
         systemBatch.execute();
         historyNode.refresh(false);
 
         AbstractJcrNode newVersion = cache().findJcrNode(Location.create(versionUuid));
 
         NodeEditor editor = node.editor();
         editor.setProperty(JcrLexicon.PREDECESSORS,
                            node.valuesFrom(PropertyType.REFERENCE, EMPTY_OBJECT_ARRAY),
                            PropertyType.REFERENCE,
                            false);
         editor.setProperty(JcrLexicon.BASE_VERSION, node.valueFrom(newVersion), false, false);
         editor.setProperty(JcrLexicon.IS_CHECKED_OUT, node.valueFrom(PropertyType.BOOLEAN, false), false, false);
         node.save();
 
         return (JcrVersionNode)newVersion;
     }
 
     /**
      * Create a version record for the given node under the given parent path with the given batch.
      * 
      * @param node the node for which the frozen version record should be created
      * @param verisonedParentPath the parent for the frozen version record for this node
      * @param batch the batch with which the frozen version should be created
      * @param onParentVersionAction the {@link OnParentVersionAction} of the node whose {@link #checkin} resulted in this node
      *        being versioned
      * @throws RepositoryException if an error occurs accessing the repository
      */
     @SuppressWarnings( "fallthrough" )
     private void versionNodeAt( AbstractJcrNode node,
                                 Path verisonedParentPath,
                                 Graph.Batch batch,
                                 int onParentVersionAction ) throws RepositoryException {
         Path childPath = path(verisonedParentPath, node.path().getLastSegment());
 
         Name primaryTypeName = node.getPrimaryTypeName();
         List<Name> mixinTypeNames = node.getMixinTypeNames();
         UUID uuid = UUID.randomUUID();
         if (node.isReferenceable()) uuid = node.uuid();
 
         switch (onParentVersionAction) {
             case OnParentVersionAction.ABORT:
                 throw new VersionException(JcrI18n.cannotCheckinNodeWithAbortChildNode.text(node.getName(), node.getParent()
                                                                                                                 .getName()));
             case OnParentVersionAction.VERSION:
                 if (node.isNodeType(JcrMixLexicon.VERSIONABLE)) {
                     JcrVersionHistoryNode history = node.getVersionHistory();
                     UUID historyUuid = history.uuid();
                     batch.create(childPath)
                          .with(JcrLexicon.PRIMARY_TYPE, JcrNtLexicon.VERSIONED_CHILD)
                          .with(JcrLexicon.CHILD_VERSION_HISTORY, historyUuid)
                          .and();
 
                     break;
                 }
 
                 // Otherwise, treat it as a copy, as per 8.2.11.2 in the 1.0.1 Spec
             case OnParentVersionAction.COPY:
                 batch.create(childPath)
                      .with(JcrLexicon.PRIMARY_TYPE, JcrNtLexicon.FROZEN_NODE)
                      .and(JcrLexicon.FROZEN_PRIMARY_TYPE, primaryTypeName)
                      .and(JcrLexicon.FROZEN_MIXIN_TYPES, mixinTypeNames)
                      .and(JcrLexicon.FROZEN_UUID, uuid)
                      .and(versionedPropertiesFor(node))
                      .and();
                 break;
             case OnParentVersionAction.INITIALIZE:
             case OnParentVersionAction.COMPUTE:
             case OnParentVersionAction.IGNORE:
                 // Do nothing for these. No built-in types require initialize or compute for child nodes.
                 return;
             default:
                 throw new IllegalStateException("Unexpected value: " + onParentVersionAction);
         }
 
         for (NodeIterator childNodes = node.getNodes(); childNodes.hasNext();) {
             AbstractJcrNode childNode = (AbstractJcrNode)childNodes.nextNode();
             versionNodeAt(childNode, childPath, batch, onParentVersionAction);
         }
 
     }
 
     /**
      * @param node the node for which the properties should be versioned
      * @return the versioned properties for {@code node} (i.e., the properties to add the the frozen version of {@code node}
      * @throws RepositoryException if an error occurs accessing the repository
      */
     private Collection<org.modeshape.graph.property.Property> versionedPropertiesFor( AbstractJcrNode node )
         throws RepositoryException {
 
         Collection<org.modeshape.graph.property.Property> props = new LinkedList<org.modeshape.graph.property.Property>();
 
         // Have to add this directly as it's not returned by AbstractJcrNode.getProperties
         AbstractJcrProperty multiValuedProperties = node.getProperty(ModeShapeIntLexicon.MULTI_VALUED_PROPERTIES);
         if (multiValuedProperties != null) props.add(multiValuedProperties.property());
 
         for (PropertyIterator iter = node.getProperties(); iter.hasNext();) {
             AbstractJcrProperty property = (AbstractJcrProperty)iter.nextProperty();
 
             org.modeshape.graph.property.Property prop = property.property();
             PropertyDefinitionId propDefnId = property.propertyInfo().getPayload().getPropertyDefinitionId();
             JcrPropertyDefinition propDefn = cache().nodeTypes().getPropertyDefinition(propDefnId);
 
             switch (propDefn.getOnParentVersion()) {
                 case OnParentVersionAction.ABORT:
                     I18n msg = JcrI18n.cannotCheckinNodeWithAbortProperty;
                     throw new VersionException(msg.text(property.getName(), node.getName()));
                 case OnParentVersionAction.COPY:
                 case OnParentVersionAction.VERSION:
                     props.add(prop);
                     break;
                 case OnParentVersionAction.INITIALIZE:
                 case OnParentVersionAction.COMPUTE:
                 case OnParentVersionAction.IGNORE:
                     // Do nothing for these
             }
         }
 
         return props;
     }
 
     /**
      * Checks out the given node, updating version-related properties on the node as needed.
      * 
      * @param node the node to be checked out
      * @throws LockException if a lock prevents the node from being checked out
      * @throws RepositoryException if an error occurs during the checkout. See {@link javax.jcr.Node#checkout()} for a full
      *         description of the possible error conditions.
      */
     void checkout( AbstractJcrNode node ) throws LockException, RepositoryException {
         session.checkLive();
         checkVersionable(node);
 
         // Check this separately since it throws a different type of exception
         if (node.isLocked() && !node.holdsLock()) {
             throw new LockException(JcrI18n.lockTokenNotHeld.text(node.getPath()));
         }
 
         /*
          * This happens when we've added mix:versionable, but not saved it to create the base
          * version (and the rest of the version storage graph).  See MODE-704.
          */
         if (!node.hasProperty(JcrLexicon.BASE_VERSION)) {
             return;
         }
 
         // Checking out an already checked-out node is supposed to return silently
         if (node.getProperty(JcrLexicon.IS_CHECKED_OUT).getBoolean()) {
             return;
         }
 
         PropertyFactory propFactory = propertyFactory();
 
         PropertyInfo<JcrPropertyPayload> mvProp = node.nodeInfo().getProperty(ModeShapeIntLexicon.MULTI_VALUED_PROPERTIES);
         org.modeshape.graph.property.Property multiValuedProps = mvProp != null ? mvProp.getProperty() : null;
 
         if (multiValuedProps == null) {
             multiValuedProps = propFactory.create(ModeShapeIntLexicon.MULTI_VALUED_PROPERTIES, JcrLexicon.PREDECESSORS);
         } else if (!Arrays.<Object>asList(multiValuedProps.getValues()).contains(JcrLexicon.PREDECESSORS)) {
             List<Object> values = new LinkedList<Object>();
 
             for (Object value : multiValuedProps) {
                 values.add(value);
             }
 
             values.add(JcrLexicon.PREDECESSORS);
             multiValuedProps = propFactory.create(ModeShapeIntLexicon.MULTI_VALUED_PROPERTIES, values);
         }
 
         ValueFactory<Reference> refFactory = context().getValueFactories().getReferenceFactory();
         Object[] oldPreds = EMPTY_OBJECT_ARRAY;
 
         AbstractJcrProperty oldPredsProperty = node.getBaseVersion().getProperty(JcrLexicon.PREDECESSORS);
         if (oldPredsProperty != null) {
             oldPreds = oldPredsProperty.property().getValuesAsArray();
         }
 
         Object[] newPreds = new Object[oldPreds.length + 1];
         newPreds[0] = refFactory.create(node.getBaseVersion().uuid());
         System.arraycopy(oldPreds, 0, newPreds, 1, oldPreds.length);
 
         org.modeshape.graph.property.Property isCheckedOut = propFactory.create(JcrLexicon.IS_CHECKED_OUT, true);
         org.modeshape.graph.property.Property predecessors = propFactory.create(JcrLexicon.PREDECESSORS, newPreds);
 
         Graph graph = workspace().graph();
         Location location = Location.create(node.uuid());
         graph.set(isCheckedOut, predecessors, multiValuedProps).on(location).and();
 
         cache().refreshProperties(location);
     }
 
     /**
      * See {@link javax.jcr.Workspace#restore(Version[], boolean)} for details of this operation.
      * 
      * @param versions the versions to be restored
      * @param removeExisting if UUID conflicts resulting from this restore should cause the conflicting node to be removed or an
      *        exception to be thrown and the operation to fail
      * @throws RepositoryException if an error occurs accessing the repository
      * @see javax.jcr.Workspace#restore(Version[], boolean)
      */
     @Override
     public void restore( Version[] versions,
                          boolean removeExisting ) throws RepositoryException {
         session.checkLive();
         if (session.hasPendingChanges()) {
             throw new InvalidItemStateException(JcrI18n.noPendingChangesAllowed.text());
         }
 
         Map<Version, AbstractJcrNode> existingVersions = new HashMap<Version, AbstractJcrNode>(versions.length);
         Set<Path> versionRootPaths = new HashSet<Path>(versions.length);
         List<Version> nonExistingVersions = new ArrayList<Version>(versions.length);
 
         for (int i = 0; i < versions.length; i++) {
             VersionHistory history = versions[i].getContainingHistory();
 
             if (history.getRootVersion().isSame(versions[i])) {
                 throw new VersionException(JcrI18n.cannotRestoreRootVersion.text(versions[i].getPath()));
             }
 
             try {
                 AbstractJcrNode existingNode = session.getNodeByIdentifier(history.getVersionableIdentifier());
                 existingVersions.put(versions[i], existingNode);
                 versionRootPaths.add(existingNode.path());
             } catch (ItemNotFoundException infe) {
                 nonExistingVersions.add(versions[i]);
             }
         }
 
         if (existingVersions.isEmpty()) {
             throw new VersionException(JcrI18n.noExistingVersionForRestore.text());
         }
 
         RestoreCommand op = new RestoreCommand(existingVersions, versionRootPaths, nonExistingVersions, null, removeExisting);
         op.execute();
 
         session.save();
     }
 
     /**
      * Restores the given version to the given path.
      * 
      * @param path the path at which the version should be restored; may not be null
      * @param version the version to restore; may not be null
      * @param labelToRestore the label that was used to identify the version; may be null
      * @param removeExisting if UUID conflicts resulting from this restore should cause the conflicting node to be removed or an
      *        exception to be thrown and the operation to fail
      * @throws RepositoryException if an error occurs accessing the repository
      * @see javax.jcr.Node#restore(Version, String, boolean)
      * @see javax.jcr.Node#restoreByLabel(String, boolean)
      */
     void restore( Path path,
                   Version version,
                   String labelToRestore,
                   boolean removeExisting ) throws RepositoryException {
         session.checkLive();
 
         if (session().hasPendingChanges()) {
             throw new InvalidItemStateException(JcrI18n.noPendingChangesAllowed.text());
         }
 
         // Ensure that the parent node exists - this will throw a PNFE if no node exists at that path
         AbstractJcrNode parentNode = cache().findJcrNode(null, path.getParent());
         AbstractJcrNode existingNode = null;
         AbstractJcrNode nodeToCheckLock;
 
         JcrVersionNode jcrVersion = (JcrVersionNode)version;
 
         try {
             existingNode = cache().findJcrNode(null, path);
             nodeToCheckLock = existingNode;
 
             // These checks only make sense if there is an existing node
             JcrVersionHistoryNode versionHistory = existingNode.getVersionHistory();
             if (!versionHistory.isSame(jcrVersion.getParent())) {
                 throw new VersionException(JcrI18n.invalidVersion.text(version.getPath(), versionHistory.getPath()));
             }
 
             if (!versionHistory.isSame(existingNode.getVersionHistory())) {
                 throw new VersionException(JcrI18n.invalidVersion.text(version.getPath(), existingNode.getVersionHistory()
                                                                                                       .getPath()));
             }
 
             if (jcrVersion.isSame(versionHistory.getRootVersion())) {
                 throw new VersionException(JcrI18n.cannotRestoreRootVersion.text(existingNode.getPath()));
             }
 
         } catch (ItemNotFoundException pnfe) {
             // This is allowable, but the node needs to be checked out
             if (!parentNode.isCheckedOut()) {
                 String parentPath = path.getString(context().getNamespaceRegistry());
                 throw new VersionException(JcrI18n.nodeIsCheckedIn.text(parentPath));
             }
 
             AbstractJcrNode sourceNode = frozenNodeFor(version);
             Name primaryTypeName = name(sourceNode.getProperty(JcrLexicon.FROZEN_PRIMARY_TYPE).property().getFirstValue());
             AbstractJcrProperty uuidProp = sourceNode.getProperty(JcrLexicon.FROZEN_UUID);
             UUID desiredUuid = uuid(uuidProp.property().getFirstValue());
 
             existingNode = parentNode.editor().createChild(path.getLastSegment().getName(), desiredUuid, primaryTypeName);
 
             nodeToCheckLock = parentNode;
         }
 
         if (nodeToCheckLock.isLocked() && !nodeToCheckLock.holdsLock()) {
             throw new LockException(JcrI18n.lockTokenNotHeld.text(nodeToCheckLock.getPath()));
         }
 
         RestoreCommand op = new RestoreCommand(Collections.singletonMap(version, existingNode),
                                                Collections.singleton(existingNode.path()), Collections.<Version>emptySet(),
                                                labelToRestore, removeExisting);
         op.execute();
 
         NodeEditor editor = existingNode.editor();
         editor.setProperty(JcrLexicon.IS_CHECKED_OUT, existingNode.valueFrom(PropertyType.BOOLEAN, false), false, false);
         editor.setProperty(JcrLexicon.BASE_VERSION, existingNode.valueFrom(jcrVersion), false, false);
 
         session().save();
 
     }
 
     /**
      * @param version the version for which the frozen node should be returned
      * @return the frozen node for the given version
      * @throws RepositoryException if an error occurs accessing the repository
      */
     AbstractJcrNode frozenNodeFor( Version version ) throws RepositoryException {
         return ((AbstractJcrNode)version).getNode(JcrLexicon.FROZEN_NODE);
     }
 
     void doneMerge( AbstractJcrNode targetNode,
                     Version version ) throws RepositoryException {
         session.checkLive();
         checkVersionable(targetNode);
 
         if (targetNode.isNew() || targetNode.isModified()) {
             throw new InvalidItemStateException(JcrI18n.noPendingChangesAllowedForNode.text());
         }
 
         if (!targetNode.isNodeType(JcrMixLexicon.VERSIONABLE)) {
             throw new VersionException(JcrI18n.requiresVersionable.text());
         }
 
         AbstractJcrProperty prop = targetNode.getProperty(JcrLexicon.PREDECESSORS);
 
         JcrValue[] values = (JcrValue[])prop.getValues();
         JcrValue[] newValues = new JcrValue[values.length + 1];
         System.arraycopy(values, 0, newValues, 0, values.length);
         newValues[values.length] = targetNode.valueFrom(version);
 
         targetNode.editor().setProperty(JcrLexicon.PREDECESSORS, newValues, PropertyType.REFERENCE, false);
 
         removeVersionFromMergeFailedProperty(targetNode, version);
 
         targetNode.save();
     }
 
     void cancelMerge( AbstractJcrNode targetNode,
                       Version version ) throws RepositoryException {
         session.checkLive();
         checkVersionable(targetNode);
 
         if (targetNode.isNew() || targetNode.isModified()) {
             throw new InvalidItemStateException(JcrI18n.noPendingChangesAllowedForNode.text());
         }
 
         if (!targetNode.isNodeType(JcrMixLexicon.VERSIONABLE)) {
             throw new UnsupportedRepositoryOperationException(JcrI18n.requiresVersionable.text());
         }
 
         removeVersionFromMergeFailedProperty(targetNode, version);
 
         targetNode.save();
     }
 
     @SuppressWarnings( "deprecation" )
     private void removeVersionFromMergeFailedProperty( AbstractJcrNode targetNode,
                                                        Version version ) throws RepositoryException {
 
         if (!targetNode.hasProperty(JcrLexicon.MERGE_FAILED)) {
             throw new VersionException(JcrI18n.versionNotInMergeFailed.text(version.getName(), targetNode.getPath()));
         }
 
         AbstractJcrProperty prop = targetNode.getProperty(JcrLexicon.MERGE_FAILED);
         Value[] values = prop.getValues();
 
         String uuidString = version.getUUID();
         int matchIndex = -1;
         for (int i = 0; i < values.length; i++) {
             if (uuidString.equals(values[i].getString())) {
                 matchIndex = i;
                 break;
             }
         }
 
         if (matchIndex == -1) {
             throw new VersionException(JcrI18n.versionNotInMergeFailed.text(version.getName(), targetNode.getPath()));
         }
 
         if (values.length == 1) {
             prop.remove();
         } else {
             Value[] newValues = new JcrValue[values.length - 2];
 
             if (matchIndex == 0) {
                 System.arraycopy(values, 1, newValues, 0, values.length - 1);
             } else if (matchIndex == values.length - 1) {
                 System.arraycopy(values, 0, newValues, 0, values.length - 2);
             } else {
                 System.arraycopy(values, 0, newValues, 0, matchIndex);
                 System.arraycopy(values, matchIndex + 1, newValues, matchIndex, values.length - matchIndex - 1);
             }
 
             prop.setValue(newValues);
         }
 
     }
 
     NodeIterator merge( AbstractJcrNode targetNode,
                         String srcWorkspace,
                         boolean bestEffort,
                         boolean isShallow ) throws RepositoryException {
         session.checkLive();
 
         if (session().hasPendingChanges()) {
             throw new InvalidItemStateException(JcrI18n.noPendingChangesAllowed.text());
         }
 
         try {
             targetNode.correspondingNodePath(srcWorkspace);
         } catch (ItemNotFoundException infe) {
             // return immediately if no corresponding node exists in that workspace
             return new JcrChildNodeIterator(Collections.<AbstractJcrNode>emptySet(), 0);
         }
 
         JcrSession sourceSession = session().with(srcWorkspace);
         MergeCommand op = new MergeCommand(targetNode, sourceSession, bestEffort, isShallow);
         op.execute();
 
         session.save();
 
         return op.getFailures();
     }
 
     /**
      * Restores the given property onto the node managed by the given editor
      * 
      * @param property the property to restore; may not be null
      * @param editor the {@link NodeEditor editor} for the node that is to be modified; may not be null
      * @throws RepositoryException if an error occurs while accessing the repository or setting the property
      */
     void restoreProperty( AbstractJcrProperty property,
                           NodeEditor editor ) throws RepositoryException {
         Name propName = property.name();
         editor.removeProperty(propName);
 
         if (property.isMultiple()) {
             JcrValue[] values = (JcrValue[])property.getValues();
             editor.setProperty(propName, values, property.getType(), false);
         } else {
             JcrValue value = (JcrValue)property.getValue();
             editor.setProperty(propName, value, false, false);
         }
     }
 
     void initializeVersionHistoryFor( AbstractJcrNode node ) throws RepositoryException {
         initializeVersionHistoryFor(node, null);
     }
 
     void initializeVersionHistoryFor( AbstractJcrNode node,
                                       UUID originalVersionUuid ) throws RepositoryException {
         Batch batch = session().createBatch();
 
         initializeVersionHistoryFor(batch, node.nodeInfo(), originalVersionUuid, true);
 
         batch.execute();
     }
 
     void initializeVersionHistoryFor( Graph.Batch batch,
                                       Node<JcrNodePayload, JcrPropertyPayload> node,
                                       UUID originalVersionUuid,
                                       boolean forceWrite ) throws RepositoryException {
 
         if (!cache().isVersionable(node)) return;
 
         /*
          * Determine if the node has already had its version history initialized based on whether the protected property
          * jcr:isCheckedOut exists.
          */
 
         boolean initialized = node.getProperty(JcrLexicon.IS_CHECKED_OUT) != null;
         if (!forceWrite && initialized) return;
 
         UUID historyUuid = UUID.randomUUID();
         UUID versionUuid = UUID.randomUUID();
 
         initializeVersionStorageFor(node, historyUuid, originalVersionUuid, versionUuid);
 
         PropertyInfo<JcrPropertyPayload> jcrUuidProp = node.getProperty(JcrLexicon.UUID);
         UUID jcrUuid = uuid(jcrUuidProp.getProperty().getFirstValue());
         Path historyPath = versionHistoryPathFor(jcrUuid);
 
         ValueFactory<Reference> refFactory = context().getValueFactories().getReferenceFactory();
         org.modeshape.graph.property.Property isCheckedOut = propertyFactory().create(JcrLexicon.IS_CHECKED_OUT, true);
         org.modeshape.graph.property.Property versionHistory = propertyFactory().create(JcrLexicon.VERSION_HISTORY,
                                                                                         refFactory.create(historyUuid));
         org.modeshape.graph.property.Property baseVersion = propertyFactory().create(JcrLexicon.BASE_VERSION,
                                                                                      refFactory.create(versionUuid));
         org.modeshape.graph.property.Property predecessors = propertyFactory().create(JcrLexicon.PREDECESSORS,
                                                                                       new Object[] {refFactory.create(versionUuid)});
 
         // This batch will get executed as part of the save
         batch.set(isCheckedOut, versionHistory, baseVersion, predecessors).on(node.getPath()).and();
 
         Path storagePath = historyPath.getParent();
         Node<JcrNodePayload, JcrPropertyPayload> storageNode = cache().findNode(null, storagePath);
 
         cache().refresh(storageNode.getNodeId(), storagePath, false);
     }
 
     void initializeVersionStorageFor( Node<JcrNodePayload, JcrPropertyPayload> node,
                                       UUID historyUuid,
                                       UUID originalVersionUuid,
                                       UUID versionUuid ) {
         JcrNodePayload payload = node.getPayload();
 
         Graph systemGraph = session().repository().createSystemGraph(context());
         Batch systemBatch = systemGraph.batch();
 
         Name primaryTypeName = payload.getPrimaryTypeName();
         List<Name> mixinTypeNames = payload.getMixinTypeNames();
 
         PropertyInfo<JcrPropertyPayload> jcrUuidProp = node.getProperty(JcrLexicon.UUID);
 
         UUID jcrUuid = uuid(jcrUuidProp.getProperty().getFirstValue());
         Path historyPath = versionHistoryPathFor(jcrUuid);
 
         systemBatch.create(historyPath)
                    .with(JcrLexicon.PRIMARY_TYPE, JcrNtLexicon.VERSION_HISTORY)
                    .and(JcrLexicon.VERSIONABLE_UUID, jcrUuid)
                    .and(JcrLexicon.UUID, historyUuid)
                    .and();
 
         if (originalVersionUuid != null) {
             systemBatch.set(JcrLexicon.COPIED_FROM).on(historyPath).to(originalVersionUuid).and();
         }
 
         Path versionLabelsPath = path(historyPath, JcrLexicon.VERSION_LABELS);
         systemBatch.create(versionLabelsPath).with(JcrLexicon.PRIMARY_TYPE, JcrNtLexicon.VERSION_LABELS).and();
 
         Path rootVersionPath = path(historyPath, JcrLexicon.ROOT_VERSION);
         DateTime now = context().getValueFactories().getDateFactory().create();
         systemBatch.create(rootVersionPath)
                    .with(JcrLexicon.PRIMARY_TYPE, JcrNtLexicon.VERSION)
                    .and(JcrLexicon.CREATED, now)
                    .and(JcrLexicon.UUID, versionUuid)
                    .and();
 
         Path frozenVersionPath = path(rootVersionPath, JcrLexicon.FROZEN_NODE);
         systemBatch.create(frozenVersionPath)
                    .with(JcrLexicon.PRIMARY_TYPE, JcrNtLexicon.FROZEN_NODE)
                    .and(JcrLexicon.FROZEN_UUID, jcrUuid)
                    .and(JcrLexicon.FROZEN_PRIMARY_TYPE, primaryTypeName)
                    .and(JcrLexicon.FROZEN_MIXIN_TYPES, mixinTypeNames)
                    .and();
 
         systemBatch.execute();
 
     }
 
     @NotThreadSafe
     private class RestoreCommand {
 
         private Map<Version, AbstractJcrNode> existingVersions;
         private Set<Path> versionRootPaths;
         private Collection<Version> nonExistingVersions;
         private boolean removeExisting;
         private String labelToRestore;
         private Map<AbstractJcrNode, AbstractJcrNode> changedNodes;
 
         public RestoreCommand( Map<Version, AbstractJcrNode> existingVersions,
                                Set<Path> versionRootPaths,
                                Collection<Version> nonExistingVersions,
                                String labelToRestore,
                                boolean removeExisting ) {
             super();
             this.existingVersions = existingVersions;
             this.versionRootPaths = versionRootPaths;
             this.nonExistingVersions = nonExistingVersions;
             this.removeExisting = removeExisting;
             this.labelToRestore = labelToRestore;
 
             // The default size for a HashMap is pretty low and this could get big fast
             this.changedNodes = new HashMap<AbstractJcrNode, AbstractJcrNode>(100);
         }
 
         void execute() throws RepositoryException {
             Collection<Version> versionsToCheck = new ArrayList<Version>(existingVersions.keySet());
             for (Version version : versionsToCheck) {
                 AbstractJcrNode root = existingVersions.get(version);
                 // This can happen if the version was already restored in another node
                 if (root == null) continue;
 
                 // This updates the changedNodes and nonExistingVersions fields as a side effect
                 restoreNodeMixins(frozenNodeFor(version), root);
                 restoreNode(frozenNodeFor(version), root, dateTime(version.getCreated()));
                 clearCheckoutStatus(frozenNodeFor(version), root);
             }
 
             if (!nonExistingVersions.isEmpty()) {
                 StringBuilder versions = new StringBuilder();
                 boolean first = true;
                 for (Version version : nonExistingVersions) {
                     if (!first) {
                         versions.append(", ");
                     } else {
                         first = false;
                     }
                     versions.append(version.getName());
                 }
                 throw new VersionException(JcrI18n.unrootedVersionsInRestore.text(versions.toString()));
             }
 
             for (Map.Entry<AbstractJcrNode, AbstractJcrNode> changedNode : changedNodes.entrySet()) {
                 restoreProperties(changedNode.getKey(), changedNode.getValue());
             }
         }
 
         /**
          * Restores the child nodes and mixin types for {@code targetNode} based on the frozen version stored at {@code
          * sourceNode}. This method will remove and add child nodes as necessary based on the documentation in the JCR 2.0
          * specification (sections 15.7), but this method will not modify properties (other than jcr:mixinTypes, jcr:baseVersion,
          * and jcr:isCheckedOut).
          * 
          * @param sourceNode a node in the subgraph of frozen nodes under a version; may not be null, but may be a node with
          *        primary type of nt:version or nt:versionedChild
          * @param targetNode the node to be updated based on {@code sourceNode}; may not be null
          * @param checkinTime the time at which the version that instigated this restore was checked in; may not be null
          * @throws RepositoryException if an error occurs accessing the repository
          */
         private void restoreNode( AbstractJcrNode sourceNode,
                                   AbstractJcrNode targetNode,
                                   DateTime checkinTime ) throws RepositoryException {
             changedNodes.put(sourceNode, targetNode);
 
             NodeEditor targetEditor = targetNode.editor();
             Node<JcrNodePayload, JcrPropertyPayload> targetNodeInfo = targetNode.nodeInfo();
             Node<JcrNodePayload, JcrPropertyPayload> sourceNodeInfo = sourceNode.nodeInfo();
 
             Set<Node<JcrNodePayload, JcrPropertyPayload>> versionedChildrenThatShouldNotBeRestored = new HashSet<Node<JcrNodePayload, JcrPropertyPayload>>();
 
             // Try to match the existing nodes with nodes from the version to be restored
             Map<Node<JcrNodePayload, JcrPropertyPayload>, Node<JcrNodePayload, JcrPropertyPayload>> presentInBoth = new HashMap<Node<JcrNodePayload, JcrPropertyPayload>, Node<JcrNodePayload, JcrPropertyPayload>>();
 
             // Start with all target children in this set and pull them out as matches are found
             List<Node<JcrNodePayload, JcrPropertyPayload>> inTargetOnly = copyOf(targetNodeInfo.getChildren(),
                                                                                  targetNodeInfo.getChildrenCount());
 
             // Start with no source children in this set, but add them in when no match is found
             Map<Node<JcrNodePayload, JcrPropertyPayload>, Node<JcrNodePayload, JcrPropertyPayload>> inSourceOnly = new HashMap<Node<JcrNodePayload, JcrPropertyPayload>, Node<JcrNodePayload, JcrPropertyPayload>>();
 
             // Map the source children to existing target children where possible
             for (Node<JcrNodePayload, JcrPropertyPayload> sourceChild : sourceNodeInfo.getChildren()) {
                 boolean isVersionedChild = JcrNtLexicon.VERSIONED_CHILD.equals(name(sourceChild.getProperty(JcrLexicon.PRIMARY_TYPE)
                                                                                                .getProperty()
                                                                                                .getFirstValue()));
                 Node<JcrNodePayload, JcrPropertyPayload> resolvedNode = resolveSourceNode(sourceChild, checkinTime);
                 Node<JcrNodePayload, JcrPropertyPayload> match = findMatchFor(resolvedNode);
 
                 if (match != null) {
                     if (isVersionedChild) {
                         if (!removeExisting) {
                             Object rawUuid = match.getProperty(JcrLexicon.UUID).getProperty().getFirstValue();
                             String uuid = rawUuid == null ? null : rawUuid.toString();
                             throw new ItemExistsException(JcrI18n.itemAlreadyExistsWithUuid.text(uuid,
                                                                                                  workspace().getName(),
                                                                                                  match.getPath()));
                         }
                         // use match directly
                         versionedChildrenThatShouldNotBeRestored.add(match);
                     }
                     inTargetOnly.remove(match);
                     presentInBoth.put(sourceChild, match);
 
                 } else {
                     inSourceOnly.put(sourceChild, resolvedNode);
                 }
             }
 
             // Remove all the extraneous children of the target node
             for (Node<JcrNodePayload, JcrPropertyPayload> targetChild : inTargetOnly) {
                 switch (nodeDefinitionFor(targetChild).getOnParentVersion()) {
                     case OnParentVersionAction.COPY:
                     case OnParentVersionAction.ABORT:
                     case OnParentVersionAction.VERSION:
                         targetEditor.destroyChild(targetChild);
                         break;
 
                     case OnParentVersionAction.COMPUTE:
                         // Technically, this should reinitialize the node per its defaults.
                     case OnParentVersionAction.INITIALIZE:
                     case OnParentVersionAction.IGNORE:
                         // Do nothing
                 }
             }
 
             LinkedList<Node<JcrNodePayload, JcrPropertyPayload>> reversedChildren = new LinkedList<Node<JcrNodePayload, JcrPropertyPayload>>();
             for (Node<JcrNodePayload, JcrPropertyPayload> sourceChild : sourceNodeInfo.getChildren()) {
                 reversedChildren.addFirst(sourceChild);
             }
 
             // Now walk through the source node children (in reversed order), inserting children as needed
             // The order is reversed because SessionCache$NodeEditor supports orderBefore, but not orderAfter
             Node<JcrNodePayload, JcrPropertyPayload> prevChild = null;
             for (Node<JcrNodePayload, JcrPropertyPayload> sourceChild : reversedChildren) {
                 Node<JcrNodePayload, JcrPropertyPayload> targetChild = presentInBoth.get(sourceChild);
                 Node<JcrNodePayload, JcrPropertyPayload> resolvedChild;
 
                 AbstractJcrNode sourceChildNode;
                 AbstractJcrNode targetChildNode;
 
                 boolean shouldRestore = !versionedChildrenThatShouldNotBeRestored.contains(targetChild);
 
                 if (targetChild != null) {
                     // Reorder if necessary
                     resolvedChild = resolveSourceNode(sourceChild, checkinTime);
 
                     sourceChildNode = cache().findJcrNode(resolvedChild.getNodeId(), resolvedChild.getPath());
                     targetChildNode = cache().findJcrNode(targetChild.getNodeId(), targetChild.getPath());
 
                 } else {
                     // Pull the resolved node
                     resolvedChild = inSourceOnly.get(sourceChild);
                     sourceChildNode = cache().findJcrNode(resolvedChild.getNodeId(), resolvedChild.getPath());
 
                     Name primaryTypeName = name(resolvedChild.getProperty(JcrLexicon.FROZEN_PRIMARY_TYPE)
                                                              .getProperty()
                                                              .getFirstValue());
                     PropertyInfo<JcrPropertyPayload> uuidProp = resolvedChild.getProperty(JcrLexicon.FROZEN_UUID);
                     UUID desiredUuid = uuid(uuidProp.getProperty().getFirstValue());
 
                     targetChildNode = targetEditor.createChild(sourceChild.getName(), desiredUuid, primaryTypeName);
 
                     assert shouldRestore == true;
                 }
 
                 if (shouldRestore) {
                     // Have to do this first, as the properties below only exist for mix:versionable nodes
                     restoreNodeMixins(sourceChildNode, targetChildNode);
 
                     if (sourceChildNode.getParent().isNodeType(JcrNtLexicon.VERSION)) {
                         clearCheckoutStatus(sourceChildNode, targetChildNode);
                     }
                     restoreNode(sourceChildNode, targetChildNode, checkinTime);
                 }
 
                 orderBefore(sourceChild, prevChild, targetEditor);
                 prevChild = sourceChild;
             }
         }
 
         private void clearCheckoutStatus( AbstractJcrNode sourceChildNode,
                                           AbstractJcrNode targetChildNode ) throws RepositoryException {
 
             NodeEditor editor = targetChildNode.editor();
             editor.setProperty(JcrLexicon.IS_CHECKED_OUT, targetChildNode.valueFrom(PropertyType.BOOLEAN, false), false, false);
             editor.setProperty(JcrLexicon.BASE_VERSION, targetChildNode.valueFrom(sourceChildNode.getParent()), false, false);
 
         }
 
         /**
          * Moves {@code targetNode} immediately before {@code beforeNode} under their shared parent. This version is very
          * inefficient in that it always tries to move the node, regardless of whether a move is actually required.
          * <p>
          * The key postcondition for this method is that {@code targetNode} must be the last "versioned" child node before {@code
          * beforeNode}, although {@code targetNode} need not be the immediate predecessor of {@code beforeNode} if all intervening
          * nodes are not "versioned". That is, there can be nodes between {@code targetNode} and {@code beforeNode} as long as
          * these nodes all have a {@link NodeDefinition node definition} with an {@link NodeDefinition#getOnParentVersion()
          * onParentVersionAction} of IGNORE, COMPUTE, or INITIALIZE.
          * </p>
          * 
          * @param targetNode the node to be reordered; may not be null
          * @param beforeNode the node that must succeed {@code targetNode}; null indicates that {@code targetNode} comes last in
          *        the list of "versionable" child nodes
          * @param parentEditor the {@link NodeEditor editor} for the parent node
          * @throws RepositoryException if an error occurs while accessing the repository
          */
         private void orderBefore( Node<JcrNodePayload, JcrPropertyPayload> targetNode,
                                   Node<JcrNodePayload, JcrPropertyPayload> beforeNode,
                                   NodeEditor parentEditor ) throws RepositoryException {
             Segment beforeSegment = beforeNode == null ? null : beforeNode.getSegment();
 
             parentEditor.orderChildBefore(targetNode.getSegment(), beforeSegment);
 
         }
 
         /**
          * Adds any missing mixin types from the source node to the target node
          * 
          * @param sourceNode the frozen source node; may not be be null
          * @param targetNode the target node; may not be null
          * @throws RepositoryException if an error occurs while accessing the repository or adding the mixin types
          */
         private void restoreNodeMixins( AbstractJcrNode sourceNode,
                                         AbstractJcrNode targetNode ) throws RepositoryException {
             AbstractJcrProperty mixinTypesProp = sourceNode.getProperty(JcrLexicon.FROZEN_MIXIN_TYPES);
             NodeEditor childEditor = targetNode.editor();
             Object[] mixinTypeNames = mixinTypesProp == null ? EMPTY_OBJECT_ARRAY : mixinTypesProp.property().getValuesAsArray();
 
             Collection<Name> currentMixinTypes = new HashSet<Name>(targetNode.getMixinTypeNames());
 
             for (int i = 0; i < mixinTypeNames.length; i++) {
                 Name mixinTypeName = name(mixinTypeNames[i]);
 
                 if (!currentMixinTypes.remove(mixinTypeName)) {
                     JcrNodeType mixinType = session().nodeTypeManager().getNodeType(mixinTypeName);
                     childEditor.addMixin(mixinType);
                 }
             }
 
         }
 
         /**
          * Restores the properties on the target node based on the stored properties on the source node. The restoration process
          * is based on the documentation in sections 8.2.7 and 8.2.11 of the JCR 1.0.1 specification.
          * 
          * @param sourceNode the frozen source node; may not be be null
          * @param targetNode the target node; may not be null
          * @throws RepositoryException if an error occurs while accessing the repository or modifying the properties
          */
         private void restoreProperties( AbstractJcrNode sourceNode,
                                         AbstractJcrNode targetNode ) throws RepositoryException {
             NodeEditor childEditor = targetNode.editor();
             Map<Name, PropertyInfo<JcrPropertyPayload>> sourcePropertyNames = new HashMap<Name, PropertyInfo<JcrPropertyPayload>>();
             for (PropertyInfo<JcrPropertyPayload> propInfo : sourceNode.nodeInfo().getProperties()) {
                 if (!IGNORED_PROP_NAMES_FOR_RESTORE.contains(propInfo.getName())) {
                     sourcePropertyNames.put(propInfo.getName(), propInfo);
                 }
             }
 
             Collection<PropertyInfo<JcrPropertyPayload>> targetProps = new ArrayList<PropertyInfo<JcrPropertyPayload>>(
                                                                                                                        targetNode.nodeInfo()
                                                                                                                                  .getProperties());
             for (PropertyInfo<JcrPropertyPayload> propInfo : targetProps) {
                 Name propName = propInfo.getName();
 
                 if (sourcePropertyNames.containsKey(propName)) {
                     // Overwrite the current property with the property from the version
                     restoreProperty(sourcePropertyNames.get(propName).getPayload().getJcrProperty(), childEditor);
                     sourcePropertyNames.remove(propName);
                 } else {
                     PropertyDefinitionId propDefnId = propInfo.getPayload().getPropertyDefinitionId();
                     PropertyDefinition propDefn = session().nodeTypeManager().getPropertyDefinition(propDefnId);
 
                     switch (propDefn.getOnParentVersion()) {
                         case OnParentVersionAction.COPY:
                         case OnParentVersionAction.ABORT:
                         case OnParentVersionAction.VERSION:
                             childEditor.removeProperty(propName);
                             break;
 
                         case OnParentVersionAction.COMPUTE:
                         case OnParentVersionAction.INITIALIZE:
                         case OnParentVersionAction.IGNORE:
                             // Do nothing
                     }
                 }
             }
 
             for (Map.Entry<Name, PropertyInfo<JcrPropertyPayload>> sourceProperty : sourcePropertyNames.entrySet()) {
                 restoreProperty(sourceProperty.getValue().getPayload().getJcrProperty(), childEditor);
             }
         }
 
         /**
          * Resolves the given source node into a frozen node. This may be as simple as returning the node itself (if it has a
          * primary type of nt:frozenNode) or converting the node to a version history, finding the best match from the versions in
          * that version history, and returning the frozen node for the best match (if the original source node has a primary type
          * of nt:versionedChild).
          * 
          * @param sourceNode the node for which the corresponding frozen node should be returned; may not be null
          * @param checkinTime the checkin time against which the versions in the version history should be matched; may not be
          *        null
          * @return the frozen node that corresponds to the give source node; may not be null
          * @throws RepositoryException if an error occurs while accessing the repository
          * @see #closestMatchFor(JcrVersionHistoryNode, DateTime)
          */
         private Node<JcrNodePayload, JcrPropertyPayload> resolveSourceNode( Node<JcrNodePayload, JcrPropertyPayload> sourceNode,
                                                                             DateTime checkinTime ) throws RepositoryException {
             Name sourcePrimaryTypeName = name(sourceNode.getProperty(JcrLexicon.PRIMARY_TYPE).getProperty().getFirstValue());
 
             if (JcrNtLexicon.FROZEN_NODE.equals(sourcePrimaryTypeName)) return sourceNode;
             assert JcrNtLexicon.VERSIONED_CHILD.equals(sourcePrimaryTypeName);
 
             // Must be a versioned child - try to see if it's one of the versions we're restoring
             PropertyInfo<JcrPropertyPayload> historyUuidProp = sourceNode.getProperty(JcrLexicon.CHILD_VERSION_HISTORY);
             UUID uuid = uuid(historyUuidProp.getProperty().getFirstValue());
             assert uuid != null;
             String uuidString = uuid.toString();
 
             /*
              * First try to find a match among the rootless versions in this restore operation
              */
             for (Version version : nonExistingVersions) {
                 if (uuidString.equals(version.getContainingHistory().getIdentifier())) {
                     JcrVersionNode versionNode = (JcrVersionNode)version;
                     nonExistingVersions.remove(version);
                     return versionNode.getFrozenNode().nodeInfo();
                 }
             }
 
             /*
              * Then check the rooted versions in this restore operation
              */
             for (Version version : existingVersions.keySet()) {
                 if (uuidString.equals(version.getContainingHistory().getIdentifier())) {
                     JcrVersionNode versionNode = (JcrVersionNode)version;
                     existingVersions.remove(version);
                     return versionNode.getFrozenNode().nodeInfo();
                 }
             }
 
             /*
              * If there was a label for this restore operation, try to match that way
              */
             JcrVersionHistoryNode versionHistory = (JcrVersionHistoryNode)cache().findJcrNode(Location.create(uuid));
 
             if (labelToRestore != null) {
                 try {
                     JcrVersionNode versionNode = versionHistory.getVersionByLabel(labelToRestore);
                     return versionNode.getFrozenNode().nodeInfo();
                 } catch (VersionException noVersionWithThatLabel) {
                     // This can happen if there's no version with that label - valid
                 }
             }
 
             /*
              * If all else fails, find the last version checked in before the checkin time for the version being restored
              */
             AbstractJcrNode match = closestMatchFor(versionHistory, checkinTime);
 
             return match.nodeInfo();
         }
 
         /**
          * Finds a node that has the same UUID as is specified in the jcr:frozenUuid property of {@code sourceNode}. If a match
          * exists and it is a descendant of one of the {@link #versionRootPaths root paths} for this restore operation, it is
          * returned. If a match exists but is not a descendant of one of the root paths for this restore operation, either an
          * exception is thrown (if {@link #removeExisting} is false) or the match is deleted and null is returned (if
          * {@link #removeExisting} is true).
          * 
          * @param sourceNode the node for which the match should be checked; may not be null
          * @return the existing node with the same UUID as is specified in the jcr:frozenUuid property of {@code sourceNode}; null
          *         if no node exists with that UUID
          * @throws ItemExistsException if {@link #removeExisting} is false and the node is not a descendant of any of the
          *         {@link #versionRootPaths root paths} for this restore command
          * @throws RepositoryException if any other error occurs while accessing the repository
          */
         private Node<JcrNodePayload, JcrPropertyPayload> findMatchFor( Node<JcrNodePayload, JcrPropertyPayload> sourceNode )
             throws ItemExistsException, RepositoryException {
 
             PropertyInfo<JcrPropertyPayload> uuidProp = sourceNode.getProperty(JcrLexicon.FROZEN_UUID);
             UUID sourceUuid = uuid(uuidProp.getProperty().getFirstValue());
 
             try {
                 AbstractJcrNode match = cache().findJcrNode(Location.create(sourceUuid));
 
                 if (nodeIsOutsideRestoredForest(match)) return null;
 
                 return match.nodeInfo();
             } catch (ItemNotFoundException infe) {
                 return null;
             }
         }
 
         /**
          * Copies the given {@link Iterable} into a {@link List} and returns that list.
          * 
          * @param rawElements the iterator containing the items that should be copied; may not be null
          * @param size the number of elements in the iterator; may not be negative, but inaccurate values will lead to a badly
          *        sized list
          * @return a list containing the same elements as {@code rawElements} in the same order; never null
          */
         private List<Node<JcrNodePayload, JcrPropertyPayload>> copyOf( Iterable<Node<JcrNodePayload, JcrPropertyPayload>> rawElements,
                                                                        int size ) {
             List<Node<JcrNodePayload, JcrPropertyPayload>> newList = new ArrayList<Node<JcrNodePayload, JcrPropertyPayload>>(size);
             for (Node<JcrNodePayload, JcrPropertyPayload> node : rawElements) {
                 newList.add(node);
             }
             return newList;
         }
 
         /**
          * Checks if the given node is outside any of the root paths for this restore command. If this occurs, a special check of
          * the {@link #removeExisting} flag must be performed.
          * 
          * @param node the node to check; may not be null
          * @return true if the node is not a descendant of any of the {@link #versionRootPaths root paths} for this restore
          *         command, false otherwise.
          * @throws ItemExistsException if {@link #removeExisting} is false and the node is not a descendant of any of the
          *         {@link #versionRootPaths root paths} for this restore command
          * @throws RepositoryException if any other error occurs while accessing the repository
          */
         private boolean nodeIsOutsideRestoredForest( AbstractJcrNode node ) throws ItemExistsException, RepositoryException {
             Path nodePath = node.path();
 
             for (Path rootPath : versionRootPaths) {
                 if (nodePath.isAtOrBelow(rootPath)) return false;
             }
 
             if (!removeExisting) {
                 throw new ItemExistsException(JcrI18n.itemAlreadyExistsWithUuid.text(node.uuid(),
                                                                                      workspace().getName(),
                                                                                      node.getPath()));
             }
 
             node.remove();
             return true;
         }
 
         /**
          * Returns the most recent version for the given version history that was checked in before the given time.
          * 
          * @param versionHistory the version history to check; may not be null
          * @param checkinTime the checkin time against which the versions in the version history should be matched; may not be
          *        null
          * @return the {@link JcrVersionNode#getFrozenNode() frozen node} under the most recent {@link Version version} for the
          *         version history that was checked in before {@code checkinTime}; never null
          * @throws RepositoryException if an error occurs accessing the repository
          */
         private AbstractJcrNode closestMatchFor( JcrVersionHistoryNode versionHistory,
                                                  DateTime checkinTime ) throws RepositoryException {
             DateTimeFactory dateFactory = context().getValueFactories().getDateFactory();
 
             VersionIterator iter = versionHistory.getAllVersions();
             Map<DateTime, Version> versions = new HashMap<DateTime, Version>((int)iter.getSize());
 
             while (iter.hasNext()) {
                 Version version = iter.nextVersion();
                 versions.put(dateFactory.create(version.getCreated()), version);
             }
 
             List<DateTime> versionDates = new ArrayList<DateTime>(versions.keySet());
             Collections.sort(versionDates);
 
             for (int i = versionDates.size() - 1; i >= 0; i--) {
                 if (versionDates.get(i).isBefore(checkinTime)) {
                     Version version = versions.get(versionDates.get(i));
                     return ((JcrVersionNode)version).getFrozenNode();
                 }
             }
 
             throw new IllegalStateException("First checkin must be before the checkin time of the node to be restored");
         }
     }
 
     @NotThreadSafe
     private class MergeCommand {
         private final Collection<AbstractJcrNode> failures;
         private final AbstractJcrNode targetNode;
         private final boolean bestEffort;
         private final boolean isShallow;
         private final JcrSession sourceSession;
         private final String workspaceName;
 
         public MergeCommand( AbstractJcrNode targetNode,
                              JcrSession sourceSession,
                              boolean bestEffort,
                              boolean isShallow ) {
             super();
             this.targetNode = targetNode;
             this.sourceSession = sourceSession;
             this.bestEffort = bestEffort;
             this.isShallow = isShallow;
 
             this.workspaceName = sourceSession.getWorkspace().getName();
             this.failures = new LinkedList<AbstractJcrNode>();
         }
 
         final JcrChildNodeIterator getFailures() {
             return new JcrChildNodeIterator(failures, failures.size());
         }
 
         void execute() throws RepositoryException {
             doMerge(targetNode);
         }
 
         /*
         let n' be the corresponding node of n in ws'. 
         if no such n' doleave(n).
 
         else if n is not versionable doupdate(n, n'). 
         else if n' is not versionable doleave(n). 
         let v be base version of n. 
         let v' be base version of n'.
         if v' is an eventual successor of v and n is not checked-in doupdate(n, n').
         else if v is equal to or an eventual predecessor of v' doleave(n). 
         else dofail(n, v').
          */
         private void doMerge( AbstractJcrNode targetNode ) throws RepositoryException {
             // n is targetNode
             // n' is sourceNode
             Path sourcePath = targetNode.correspondingNodePath(workspaceName);
 
             AbstractJcrNode sourceNode;
             try {
                 sourceNode = sourceSession.getNode(sourcePath);
             } catch (ItemNotFoundException infe) {
                 doLeave(targetNode);
                 return;
             }
 
             if (!targetNode.isNodeType(JcrMixLexicon.VERSIONABLE)) {
                 doUpdate(targetNode, sourceNode);
                 return;
             } else if (!sourceNode.isNodeType(JcrMixLexicon.VERSIONABLE)) {
                 doLeave(targetNode);
                 return;
             }
 
             JcrVersionNode sourceVersion = sourceNode.getBaseVersion();
             JcrVersionNode targetVersion = targetNode.getBaseVersion();
 
             if (sourceVersion.isSuccessorOf(targetVersion) && !targetNode.isCheckedOut()) {
                 doUpdate(targetNode, sourceNode);
                 return;
             }
 
             if (targetVersion.isSuccessorOf(sourceVersion) || targetVersion.uuid().equals(sourceVersion.uuid())) {
                 doLeave(targetNode);
                 return;
             }
 
             doFail(targetNode, sourceVersion);
         }
 
         /*
         if isShallow = false
             for each child node c of n domerge(c).
          */
         private void doLeave( AbstractJcrNode targetNode ) throws RepositoryException {
             if (isShallow == false) {
 
                 for (NodeIterator iter = targetNode.getNodes(); iter.hasNext();) {
                     doMerge((AbstractJcrNode)iter.nextNode());
                 }
             }
         }
 
         /*
         replace set of properties of n with those of n'. 
         let S be the set of child nodes of n. 
         let S' be the set of child nodes of n'. 
 
         judging by the name of the child node:
         let C be the set of nodes in S and in S' 
         let D be the set of nodes in S but not in S'. 
         let D' be the set of nodes in S' but not in S.
         remove from n all child nodes in D. 
         for each child node of n' in D' copy it (and its subtree) to n
         as a new child node (if an incoming node has the same UUID as a node already existing in this workspace, the already existing node is removed).
         for each child node m of n in C domerge(m).
          */
         private void doUpdate( AbstractJcrNode targetNode,
                                AbstractJcrNode sourceNode ) throws RepositoryException {
             restoreProperties(sourceNode, targetNode);
 
             LinkedHashMap<String, AbstractJcrNode> sourceNodes = childNodeMapFor(sourceNode);
             LinkedHashMap<String, AbstractJcrNode> targetNodes = childNodeMapFor(targetNode);
 
             // D' set in algorithm above
             Map<String, AbstractJcrNode> sourceOnly = new LinkedHashMap<String, AbstractJcrNode>(sourceNodes);
             sourceOnly.keySet().removeAll(targetNodes.keySet());
 
             for (AbstractJcrNode node : sourceOnly.values()) {
                 workspace().copy(workspaceName, node.getPath(), targetNode.getPath() + "/" + node.getName());
             }
 
             // D set in algorithm above
             LinkedHashMap<String, AbstractJcrNode> targetOnly = new LinkedHashMap<String, AbstractJcrNode>(targetNodes);
             targetOnly.keySet().removeAll(targetOnly.keySet());
 
             for (AbstractJcrNode node : targetOnly.values()) {
                 node.remove();
             }
 
             // C set in algorithm above
             Map<String, AbstractJcrNode> presentInBoth = new HashMap<String, AbstractJcrNode>(targetNodes);
             presentInBoth.keySet().retainAll(sourceNodes.keySet());
             for (AbstractJcrNode node : presentInBoth.values()) {
                 if (isShallow && node.isNodeType(JcrMixLexicon.VERSIONABLE)) continue;
                 doMerge(node);
             }
         }
 
         private LinkedHashMap<String, AbstractJcrNode> childNodeMapFor( AbstractJcrNode node ) throws RepositoryException {
             LinkedHashMap<String, AbstractJcrNode> childNodes = new LinkedHashMap<String, AbstractJcrNode>();
 
             for (NodeIterator iter = node.getNodes(); iter.hasNext();) {
                 AbstractJcrNode child = (AbstractJcrNode)iter.nextNode();
                 childNodes.put(child.getName(), child);
             }
 
             return childNodes;
         }
 
         /*
         if bestEffort = false throw MergeException. 
         else add identifier of v' (if not already present) to the
             jcr:mergeFailed property of n, 
             add identifier of n to failedset, 
             if isShallow = false 
                 for each versionable child node c of n domerge(c)
          */
 
         private void doFail( AbstractJcrNode targetNode,
                              JcrVersionNode sourceVersion ) throws RepositoryException {
             if (!bestEffort) {
                 throw new MergeException();
             }
 
             NodeEditor targetEditor = targetNode.editor();
             if (targetNode.hasProperty(JcrLexicon.MERGE_FAILED)) {
                 JcrValue[] existingValues = (JcrValue[])targetNode.getProperty(JcrLexicon.MERGE_FAILED).getValues();
 
                 boolean found = false;
                 String sourceUuidString = sourceVersion.uuid().toString();
                 for (int i = 0; i < existingValues.length; i++) {
                     if (sourceUuidString.equals(existingValues[i].getString())) {
                         found = true;
                         break;
                     }
                 }
 
                 if (!found) {
                     JcrValue[] newValues = new JcrValue[existingValues.length + 1];
                     System.arraycopy(existingValues, 0, newValues, 0, existingValues.length);
                     newValues[newValues.length - 1] = targetNode.valueFrom(sourceVersion);
                     targetEditor.setProperty(JcrLexicon.MERGE_FAILED, newValues, PropertyType.REFERENCE, false);
                 }
 
             } else {
                 targetEditor.setProperty(JcrLexicon.MERGE_FAILED, targetNode.valueFrom(sourceVersion), false, false);
             }
             failures.add(targetNode);
 
             if (isShallow == false) {
                 for (NodeIterator iter = targetNode.getNodes(); iter.hasNext();) {
                     AbstractJcrNode childNode = (AbstractJcrNode)iter.nextNode();
 
                     if (childNode.isNodeType(JcrMixLexicon.VERSIONABLE)) {
                         doMerge(childNode);
                     }
                 }
             }
         }
 
         /**
          * Restores the properties on the target node based on the stored properties on the source node. The restoration process
          * involves copying over all of the properties on the source to the target.
          * 
          * @param sourceNode the source node; may not be be null
          * @param targetNode the target node; may not be null
          * @throws RepositoryException if an error occurs while accessing the repository or modifying the properties
          */
         private void restoreProperties( AbstractJcrNode sourceNode,
                                         AbstractJcrNode targetNode ) throws RepositoryException {
             NodeEditor childEditor = targetNode.editor();
             Map<Name, PropertyInfo<JcrPropertyPayload>> sourcePropertyNames = new HashMap<Name, PropertyInfo<JcrPropertyPayload>>();
             for (PropertyInfo<JcrPropertyPayload> propInfo : sourceNode.nodeInfo().getProperties()) {
                 if (!IGNORED_PROP_NAMES_FOR_RESTORE.contains(propInfo.getName())) {
                     sourcePropertyNames.put(propInfo.getName(), propInfo);
                 }
             }
 
             Collection<PropertyInfo<JcrPropertyPayload>> targetProps = new ArrayList<PropertyInfo<JcrPropertyPayload>>(
                                                                                                                        targetNode.nodeInfo()
                                                                                                                                  .getProperties());
             for (PropertyInfo<JcrPropertyPayload> propInfo : targetProps) {
                 Name propName = propInfo.getName();
 
                 if (sourcePropertyNames.containsKey(propName)) {
                     // Overwrite the current property with the property from the version
                     restoreProperty(sourcePropertyNames.get(propName).getPayload().getJcrProperty(), childEditor);
                     sourcePropertyNames.remove(propName);
                 } else {
                     PropertyDefinitionId propDefnId = propInfo.getPayload().getPropertyDefinitionId();
                     PropertyDefinition propDefn = session().nodeTypeManager().getPropertyDefinition(propDefnId);
 
                     switch (propDefn.getOnParentVersion()) {
                         case OnParentVersionAction.COPY:
                         case OnParentVersionAction.ABORT:
                         case OnParentVersionAction.VERSION:
                             childEditor.removeProperty(propName);
                             break;
 
                         case OnParentVersionAction.COMPUTE:
                         case OnParentVersionAction.INITIALIZE:
                         case OnParentVersionAction.IGNORE:
                             // Do nothing
                     }
                 }
             }
 
             for (Map.Entry<Name, PropertyInfo<JcrPropertyPayload>> sourceProperty : sourcePropertyNames.entrySet()) {
                 restoreProperty(sourceProperty.getValue().getPayload().getJcrProperty(), childEditor);
             }
         }
 
     }
 
     @Override
     public void cancelMerge( String absPath,
                              Version version ) throws VersionException, InvalidItemStateException, RepositoryException {
         cancelMerge(session.getNode(absPath), version);
     }
 
     /**
      * Throw an {@link UnsupportedRepositoryOperationException} if the node is not versionable (i.e.,
      * isNodeType(JcrMixLexicon.VERSIONABLE) == false).
      * 
      * @param node the node to check
      * @throws UnsupportedRepositoryOperationException if <code>!isNodeType({@link JcrMixLexicon#VERSIONABLE})</code>
      * @throws RepositoryException if an error occurs reading the node types for this node
      */
     private void checkVersionable( AbstractJcrNode node ) throws UnsupportedRepositoryOperationException, RepositoryException {
         if (!node.isNodeType(JcrMixLexicon.VERSIONABLE)) {
             throw new UnsupportedRepositoryOperationException(JcrI18n.requiresVersionable.text());
         }
     }
 
     @Override
     public Version checkin( String absPath )
         throws VersionException, InvalidItemStateException, LockException, RepositoryException {
         return checkin(session.getNode(absPath));
     }
 
     @Override
     public void checkout( String absPath ) throws LockException, RepositoryException {
         checkout(session.getNode(absPath));
     }
 
     @Override
     public Version checkpoint( String absPath )
         throws VersionException, InvalidItemStateException, LockException, RepositoryException {
         Version version = checkin(absPath);
         checkout(absPath);
         return version;
     }
 
     @Override
     public void doneMerge( String absPath,
                            Version version ) throws VersionException, InvalidItemStateException, RepositoryException {
         doneMerge(session.getNode(absPath), version);
     }
 
     @Override
     public javax.jcr.Node getActivity() throws UnsupportedRepositoryOperationException, RepositoryException {
         throw new UnsupportedRepositoryOperationException();
     }
 
     @Override
     public Version getBaseVersion( String absPath ) throws RepositoryException {
         return session.getNode(absPath).getBaseVersion();
     }
 
     @Override
     public VersionHistory getVersionHistory( String absPath ) throws UnsupportedRepositoryOperationException, RepositoryException {
         return session.getNode(absPath).getVersionHistory();
     }
 
     @Override
     public boolean isCheckedOut( String absPath ) throws RepositoryException {
         AbstractJcrNode node = session.getNode(absPath);
         return node.isCheckedOut();
     }
 
     @SuppressWarnings( "unused" )
     @Override
     public NodeIterator merge( javax.jcr.Node activityNode )
         throws VersionException, AccessDeniedException, MergeException, LockException, InvalidItemStateException,
         RepositoryException {
         throw new UnsupportedRepositoryOperationException();
     }
 
     @Override
     public NodeIterator merge( String absPath,
                                String srcWorkspace,
                                boolean bestEffort,
                                boolean isShallow )
         throws NoSuchWorkspaceException, AccessDeniedException, MergeException, LockException, InvalidItemStateException,
         RepositoryException {
         CheckArg.isNotNull(srcWorkspace, "source workspace name");
 
         AbstractJcrNode node = session.getNode(absPath);
 
         return merge(node, srcWorkspace, bestEffort, isShallow);
     }
 
     @Override
     public NodeIterator merge( String absPath,
                                String srcWorkspace,
                                boolean bestEffort )
         throws NoSuchWorkspaceException, AccessDeniedException, MergeException, LockException, InvalidItemStateException,
         RepositoryException {
         return merge(absPath, srcWorkspace, bestEffort, false);
     }
 
     @Override
     public void restore( String absPath,
                          String versionName,
                          boolean removeExisting )
         throws VersionException, ItemExistsException, LockException, InvalidItemStateException, RepositoryException {
 
         Version version = null;
 
         // See if the node at absPath exists and has version storage.
         Path path = session.pathFor(absPath, "absPath");
 
         AbstractJcrNode existingNode = session.getNode(path);
         VersionHistory historyNode = existingNode.getVersionHistory();
         if (historyNode != null) {
             version = historyNode.getVersion(versionName);
         }
 
         assert version != null;
 
         // AbstractJcrNode versionStorage = session.getRootNode().getNode(JcrLexicon.SYSTEM).getNode(JcrLexicon.VERSION_STORAGE);
         // assert versionStorage != null;
 
         restore(path, version, null, removeExisting);
     }
 
     @Override
     public void restore( String absPath,
                          Version version,
                          boolean removeExisting )
         throws PathNotFoundException, ItemExistsException, VersionException, ConstraintViolationException, LockException,
         InvalidItemStateException, RepositoryException {
         Path path = session.pathFor(absPath, "absPath");
 
         restore(path, version, null, removeExisting);
     }
 
     @Override
     public void restore( Version version,
                          boolean removeExisting )
         throws VersionException, ItemExistsException, InvalidItemStateException, LockException, RepositoryException {
         AbstractJcrNode node = session.getNodeByIdentifier(version.getContainingHistory().getVersionableIdentifier());
         Path path = node.path();
 
         restore(path, version, null, removeExisting);
     }
 
     @Override
     public void restoreByLabel( String absPath,
                                 String versionLabel,
                                 boolean removeExisting )
         throws VersionException, ItemExistsException, LockException, InvalidItemStateException, RepositoryException {
         session.getNode(absPath).restoreByLabel(versionLabel, removeExisting);
     }
 
     @Override
     public javax.jcr.Node setActivity( javax.jcr.Node activity )
         throws UnsupportedRepositoryOperationException, RepositoryException {
         throw new UnsupportedRepositoryOperationException();
     }
 
     @SuppressWarnings( "unused" )
     @Override
     public void removeActivity( javax.jcr.Node activityNode )
         throws UnsupportedRepositoryOperationException, VersionException, RepositoryException {
         throw new UnsupportedRepositoryOperationException();
     }
 
     @Override
     public javax.jcr.Node createActivity( String title ) throws UnsupportedRepositoryOperationException, RepositoryException {
         throw new UnsupportedRepositoryOperationException();
     }
 
     @Override
     public javax.jcr.Node createConfiguration( String absPath )
         throws UnsupportedRepositoryOperationException, RepositoryException {
         throw new UnsupportedRepositoryOperationException();
     }
 
 }