Moved dangerous helper methods out of AVMService.

Reworked handling of path lookup failures to not throw exceptions
internally, to improve performance of certain layered directory
operations.  Unfortunately there remains at least one scenario,
handling of bulk loads, and promotions of deeply nested directories in
layered contexts, in which performance is considerably less than
ideal. 

Made AVMService.createBranch() and AVMSyncService.update() perform
implicit snapshots of source tree's stores before proceeding.


git-svn-id: https://svn.alfresco.com/repos/alfresco-enterprise/alfresco/BRANCHES/WCM-DEV2/root@3812 c4b6b30b-aa2e-2d43-bbcb-ca4b014f7261

config/alfresco/public-services-context.xml

@@ -1058,6 +1058,9 @@
         <property name="avmService">
             <ref bean="avmService"/>
         </property>
+        <property name="avmRepository">
+            <ref bean="avmRepository"/>
+        </property>
     </bean>
     
     <bean id="AVMSyncService_descriptor" parent="AlfrescoServiceDescriptor">

source/java/org/alfresco/repo/avm/AVMRepository.java

@@ -105,8 +105,12 @@ public class AVMRepository
     {
         fLookupCount.set(1);
         String[] pathParts = SplitPath(path);
-        AVMStore rep = getAVMStoreByName(pathParts[0]);
+        AVMStore store = getAVMStoreByName(pathParts[0]);
-        return rep.createFile(pathParts[1], name);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
+        return store.createFile(pathParts[1], name);
     }
 
     /**
@@ -119,8 +123,12 @@ public class AVMRepository
     {
         fLookupCount.set(1);
         String[] pathParts = SplitPath(path);
-        AVMStore rep = getAVMStoreByName(pathParts[0]);
+        AVMStore store = getAVMStoreByName(pathParts[0]);
-        rep.createFile(pathParts[1], name, data);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
+        store.createFile(pathParts[1], name, data);
     }
     
     /**
@@ -132,8 +140,12 @@ public class AVMRepository
     {
         fLookupCount.set(1);
         String[] pathParts = SplitPath(path);
-        AVMStore rep = getAVMStoreByName(pathParts[0]);
+        AVMStore store = getAVMStoreByName(pathParts[0]);
-        rep.createDirectory(pathParts[1], name);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
+        store.createDirectory(pathParts[1], name);
     }
 
     /**
@@ -157,6 +169,10 @@ public class AVMRepository
         // We need the store to do anything so...
         String [] pathParts = SplitPath(parent.getPath());
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         DirectoryNode dir = (DirectoryNode)node;
         DirectoryNode child = null;
         if (dir instanceof LayeredDirectoryNode)
@@ -188,9 +204,12 @@ public class AVMRepository
         }
         fLookupCount.set(1);
         String[] pathParts = SplitPath(dstPath);
-        AVMStore rep = getAVMStoreByName(pathParts[0]);
+        AVMStore store = getAVMStoreByName(pathParts[0]);
-//        fSession.get().lock(rep, LockMode.UPGRADE);
+        if (store == null)
-        rep.createLayeredDirectory(srcPath, pathParts[1], name);
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
+        store.createLayeredDirectory(srcPath, pathParts[1], name);
     }
 
     /**
@@ -203,8 +222,12 @@ public class AVMRepository
     {
         fLookupCount.set(1);
         String[] pathParts = SplitPath(dstPath);
-        AVMStore rep = getAVMStoreByName(pathParts[0]);
+        AVMStore store = getAVMStoreByName(pathParts[0]);
-        rep.createLayeredFile(srcPath, pathParts[1], name);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
+        store.createLayeredFile(srcPath, pathParts[1], name);
     }
 
     /**
@@ -213,15 +236,10 @@ public class AVMRepository
      */
     public void createAVMStore(String name)
     {
-        try
+        if (getAVMStoreByName(name) != null)
         {
-            getAVMStoreByName(name);
             throw new AVMExistsException("AVMStore exists: " + name);
         }
-        catch (AVMNotFoundException anf)
-        {
-            // Do nothing.
-        }
         // Newing up the object causes it to be written to the db.
         @SuppressWarnings("unused") 
         AVMStore rep = new AVMStoreImpl(this, name);
@@ -246,12 +264,32 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(srcPath);
         AVMStore srcRepo = getAVMStoreByName(pathParts[0]);
+        if (srcRepo == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
+        if (version < 0)
+        {
+            version = srcRepo.createSnapshot();
+        }
         Lookup sPath = srcRepo.lookup(version, pathParts[1], false, false);
+        if (sPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         // Lookup the destination directory.
         fLookupCount.set(1);
         pathParts = SplitPath(dstPath);
         AVMStore dstRepo = getAVMStoreByName(pathParts[0]);
+        if (dstRepo == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         Lookup dPath = dstRepo.lookupDirectory(-1, pathParts[1], true);
+        if (dPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         DirectoryNode dirNode = (DirectoryNode)dPath.getCurrentNode();
         AVMNode srcNode = sPath.getCurrentNode();
         AVMNode dstNode = null;
@@ -291,8 +329,12 @@ public class AVMRepository
     {
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
-        AVMStore rep = getAVMStoreByName(pathParts[0]);
+        AVMStore store = getAVMStoreByName(pathParts[0]);
-        return rep.getOutputStream(pathParts[1]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
+        return store.getOutputStream(pathParts[1]);
     }
     
     /**
@@ -313,7 +355,15 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(srcPath);
         AVMStore srcRepo = getAVMStoreByName(pathParts[0]);
+        if (srcRepo == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         Lookup sPath = srcRepo.lookupDirectory(-1, pathParts[1], true);
+        if (sPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         DirectoryNode srcDir = (DirectoryNode)sPath.getCurrentNode();
         AVMNode srcNode = srcDir.lookupChild(sPath, srcName, -1, true, false);
         if (srcNode == null)
@@ -323,7 +373,15 @@ public class AVMRepository
         fLookupCount.set(1);
         pathParts = SplitPath(dstPath);
         AVMStore dstRepo = getAVMStoreByName(pathParts[0]);
+        if (dstRepo == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         Lookup dPath = dstRepo.lookupDirectory(-1, pathParts[1], true);
+        if (dPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         DirectoryNode dstDir = (DirectoryNode)dPath.getCurrentNode();
         AVMNode dstNode = dstDir.lookupChild(dPath, dstName, -1, true, false);
         if (dstNode != null)
@@ -425,8 +483,12 @@ public class AVMRepository
     {
         fLookupCount.set(1);
         String [] pathParts = SplitPath(dirPath);
-        AVMStore repo = getAVMStoreByName(pathParts[0]);
+        AVMStore store = getAVMStoreByName(pathParts[0]);
-        repo.uncover(pathParts[1], name);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
+        store.uncover(pathParts[1], name);
     }
 
     /**
@@ -439,8 +501,12 @@ public class AVMRepository
         List<Integer> result = new ArrayList<Integer>();
         for (String repName : repositories)
         {
-            AVMStore repo = getAVMStoreByName(repName);
+            AVMStore store = getAVMStoreByName(repName);
-            result.add(repo.createSnapshot());
+            if (store == null)
+            {
+                throw new AVMNotFoundException("Store not found.");
+            }
+            result.add(store.createSnapshot());
         }
         return result;
     }
@@ -453,6 +519,10 @@ public class AVMRepository
     public int createSnapshot(String storeName)
     {
         AVMStore store = getAVMStoreByName(storeName);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         return store.createSnapshot();
     }
 
@@ -466,6 +536,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }        
         store.removeNode(pathParts[1], name);
     }
 
@@ -478,6 +552,10 @@ public class AVMRepository
     public void purgeAVMStore(String name)
     {
         AVMStore store = getAVMStoreByName(name);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         AVMNode root = store.getRoot();
         root.setIsRoot(false);
         VersionRootDAO vrDAO = AVMContext.fgInstance.fVersionRootDAO;
@@ -505,6 +583,10 @@ public class AVMRepository
     public void purgeVersion(String name, int version)
     {
         AVMStore store = getAVMStoreByName(name);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         store.purgeVersion(version);
     }
 
@@ -519,6 +601,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         return store.getInputStream(version, pathParts[1]);
     }
 
@@ -535,6 +621,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         return store.getListing(version, pathParts[1], includeDeleted);
     }
 
@@ -550,6 +640,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         return store.getListingDirect(version, pathParts[1], includeDeleted);
     }
     
@@ -612,6 +706,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         return store.getDeleted(version, pathParts[1]);
     }
     
@@ -639,6 +737,10 @@ public class AVMRepository
     public AVMStoreDescriptor getAVMStore(String name)
     {
         AVMStore store = getAVMStoreByName(name);
+        if (store == null)
+        {
+            return null;
+        }
         return store.getDescriptor();
     }
     
@@ -650,6 +752,10 @@ public class AVMRepository
     public List<VersionDescriptor> getAVMStoreVersions(String name)
     {
         AVMStore store = getAVMStoreByName(name);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         return store.getVersions();
     }
 
@@ -664,6 +770,10 @@ public class AVMRepository
     public List<VersionDescriptor> getAVMStoreVersions(String name, Date from, Date to)
     {
         AVMStore store = getAVMStoreByName(name);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         return store.getVersions(from, to);
     }
     
@@ -696,6 +806,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         return store.getIndirectionPath(version, pathParts[1]);
     }
 
@@ -707,6 +821,10 @@ public class AVMRepository
     public int getLatestVersionID(String name)
     {
         AVMStore store = getAVMStoreByName(name);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         return store.getNextVersionID();
     }
     
@@ -717,12 +835,7 @@ public class AVMRepository
      */
     private AVMStore getAVMStoreByName(String name)
     {
-        AVMStore store = AVMContext.fgInstance.fAVMStoreDAO.getByName(name);
+        return AVMContext.fgInstance.fAVMStoreDAO.getByName(name);
-        if (store == null)
-        {
-            throw new AVMNotFoundException("AVMStore not found: " + name);
-        }
-        return store;
     }
 
     /**
@@ -768,8 +881,11 @@ public class AVMRepository
             }
             String [] pathParts = SplitPath(path);
             AVMStore store = getAVMStoreByName(pathParts[0]);
-            Lookup result = store.lookup(version, pathParts[1], false, includeDeleted);
+            if (store == null)
-            return result;
+            {
+                return null;
+            }
+            return store.lookup(version, pathParts[1], false, includeDeleted);
         }
         finally
         {
@@ -780,6 +896,7 @@ public class AVMRepository
         }
     }
     
+    // TODO This should really return null for not found.
     /**
      * Lookup a descriptor from a directory descriptor.
      * @param dir The directory descriptor.
@@ -814,7 +931,15 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         Lookup lookup = store.lookup(version, pathParts[1], false, false);
+        if (lookup == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         return new LayeringDescriptor(!lookup.getDirectlyContained(),
                                       lookup.getAVMStore().getDescriptor(),
                                       lookup.getFinalStore().getDescriptor());
@@ -834,6 +959,10 @@ public class AVMRepository
         }
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            return null;
+        }
         return store.lookupDirectory(version, pathParts[1], false);
     }
 
@@ -861,6 +990,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String[] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         store.makePrimary(pathParts[1]);
     }
 
@@ -874,6 +1007,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String[] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         store.retargetLayeredDirectory(pathParts[1], target);
     }
     
@@ -918,6 +1055,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String[] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         store.setOpacity(pathParts[1], opacity);
     }
         
@@ -932,6 +1073,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         store.setNodeProperty(pathParts[1], name, value);
     }
     
@@ -945,6 +1090,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         store.setNodeProperties(pathParts[1], properties);
     }
     
@@ -960,6 +1109,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         return store.getNodeProperty(version, pathParts[1], name);
     }
     
@@ -974,6 +1127,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         return store.getNodeProperties(version, pathParts[1]);
     }
     
@@ -987,6 +1144,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         store.deleteNodeProperty(pathParts[1], name);
     }
 
@@ -999,6 +1160,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         store.deleteNodeProperties(pathParts[1]);
     }
     
@@ -1010,7 +1175,12 @@ public class AVMRepository
      */
     public void setStoreProperty(String store, QName name, PropertyValue value)
     {
-        getAVMStoreByName(store).setProperty(name, value);
+        AVMStore st = getAVMStoreByName(store);
+        if (st == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
+        st.setProperty(name, value);
     }
     
     /**
@@ -1020,7 +1190,12 @@ public class AVMRepository
      */
     public void setStoreProperties(String store, Map<QName, PropertyValue> props)
     {
-        getAVMStoreByName(store).setProperties(props);
+        AVMStore st = getAVMStoreByName(store);
+        if (st == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
+        st.setProperties(props);
     }
     
     /**
@@ -1031,7 +1206,16 @@ public class AVMRepository
      */
     public PropertyValue getStoreProperty(String store, QName name)
     {
-        return getAVMStoreByName(store).getProperty(name);
+        if (store == null)
+        {
+            throw new AVMBadArgumentException("Null store name.");
+        }
+        AVMStore st = getAVMStoreByName(store);
+        if (st == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
+        return st.getProperty(name);
     }
     
     /**
@@ -1042,8 +1226,13 @@ public class AVMRepository
      */
     public Map<QName, PropertyValue> queryStorePropertyKey(String store, QName keyPattern)
     {
+        AVMStore st = getAVMStoreByName(store);
+        if (st == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         List<AVMStoreProperty> matches =
-            AVMContext.fgInstance.fAVMStorePropertyDAO.queryByKeyPattern(getAVMStoreByName(store),
+            AVMContext.fgInstance.fAVMStorePropertyDAO.queryByKeyPattern(st,
                                                                          keyPattern);
         Map<QName, PropertyValue> results = new HashMap<QName, PropertyValue>();
         for (AVMStoreProperty prop : matches)
@@ -1086,7 +1275,16 @@ public class AVMRepository
      */
     public Map<QName, PropertyValue> getStoreProperties(String store)
     {
-        return getAVMStoreByName(store).getProperties();
+        if (store == null)
+        {
+            throw new AVMBadArgumentException("Null store name.");
+        }
+        AVMStore st = getAVMStoreByName(store);
+        if (st == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
+        return st.getProperties();
     }
     
     /**
@@ -1096,17 +1294,12 @@ public class AVMRepository
      */
     public void deleteStoreProperty(String store, QName name)
     {
-        getAVMStoreByName(store).deleteProperty(name);
+        AVMStore st = getAVMStoreByName(store);
-    }
+        if (st == null)
-    
+        {
-    /**
+            throw new AVMNotFoundException("Store not found.");
-     * Get the AVMStoreDescriptor for an AVMStore.
+        }
-     * @param name The name of the AVMStore.
+        st.deleteProperty(name);
-     * @return The descriptor.
-     */
-    public AVMStoreDescriptor getAVMStoreDescriptor(String name)
-    {
-        return getAVMStoreByName(name).getDescriptor();
     }
     
     /**
@@ -1179,6 +1372,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         return store.getContentDataForWrite(pathParts[1]);
     }
 
@@ -1192,6 +1389,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }        
         store.setContentData(pathParts[1], data);
     }
     
@@ -1214,6 +1415,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         store.addAspect(pathParts[1], aspectName);
     }
     
@@ -1228,6 +1433,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         return store.getAspects(version, pathParts[1]);
     }
     
@@ -1241,6 +1450,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         store.removeAspect(pathParts[1], aspectName);
     }
     
@@ -1256,6 +1469,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         return store.hasAspect(version, pathParts[1], aspectName);
     }
     
@@ -1269,6 +1486,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         store.setACL(pathParts[1], acl);
     }
     
@@ -1283,6 +1504,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         return store.getACL(version, pathParts[1]);
     }
     
@@ -1297,6 +1522,10 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(parentPath);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         store.link(pathParts[1], name, toLink);
     }
     
@@ -1353,8 +1582,16 @@ public class AVMRepository
         fLookupCount.set(1);
         String [] pathParts = SplitPath(path);
         AVMStore store = getAVMStoreByName(pathParts[0]);
+        if (store == null)
+        {
+            throw new AVMNotFoundException("Store not found.");
+        }
         // Just force a copy if needed by looking up in write mode.
         Lookup lPath = store.lookup(-1, pathParts[1], true, false);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         AVMNode node = lPath.getCurrentNode();
         return node.getDescriptor(lPath);
     }

source/java/org/alfresco/repo/avm/AVMServiceImpl.java

@@ -307,22 +307,6 @@ public class AVMServiceImpl implements AVMService
         fAVMRepository.createDirectory(path, name);
     }
 
-    /**
-     * Create a new directory, in an already copy on written node.
-     * This should only be used if you really know what you're doing.
-     * @param parent The parent node.
-     * @param name The name of the new directory.
-     * @return A descriptor for the newly created directory.
-     */
-    public AVMNodeDescriptor createDirectory(AVMNodeDescriptor parent, String name)
-    {
-        if (parent == null || name == null)
-        {
-            throw new AVMBadArgumentException("Illegal null argument.");
-        }
-        return fAVMRepository.createDirectory(parent, name);
-    }
-
     /**
      * Create a new layered file.  It must not exist.
      * @param srcPath The src path.  Ie the target for the layering.
@@ -511,6 +495,10 @@ public class AVMServiceImpl implements AVMService
         try
         {
             Lookup lookup = fAVMRepository.lookup(version, path, includeDeleted);
+            if (lookup == null)
+            {
+                return null;
+            }
             return lookup.getCurrentNode().getDescriptor(lookup);
         }
         catch (AVMNotFoundException e)
@@ -1082,42 +1070,6 @@ public class AVMServiceImpl implements AVMService
         fAVMRepository.link(parentPath, name, toLink);
     }
 
-    /**
-     * This is a more dangerous version of link, which assumes
-     * that copy on write has occurred for the parent node. This is
-     * an internal call. Don't use it if you don't know precisely
-     * what you are doing.
-     * @param parent The parent node.
-     * @param name The name to give the child.
-     * @param child The child node to link.
-     */
-    public void link(AVMNodeDescriptor parent, String name, AVMNodeDescriptor child)
-    {
-        if (parent == null || child == null)
-        {
-            throw new AVMBadArgumentException("Illegal Null Argument.");
-        }
-        fAVMRepository.link(parent, name, child);
-    }
-    
-    /**
-     * Flatten a direct child of a layered directory. This does
-     * the equivalent of removing the given child from the directory 
-     * and then doing an uncover. This routine makes many dangerous 
-     * assumptions and is only for use by AVMSyncService. Don't use it
-     * if you don't know precisely what you are doing.
-     * @param lDir The layered directory node.
-     * @param name The name to flatten.
-     */
-    public void flatten(AVMNodeDescriptor lDir, String name)
-    {
-        if (lDir == null || name == null)
-        {
-            throw new AVMBadArgumentException("Illegal Null Argument.");
-        }
-        fAVMRepository.flatten(lDir, name);
-    }
-
     /**
      * Force copy on write of a path.
      * @param path The path to force.

source/java/org/alfresco/repo/avm/AVMServiceTest.java

@@ -59,6 +59,61 @@ import org.alfresco.service.transaction.TransactionService;
  */
 public class AVMServiceTest extends AVMServiceTestBase
 {
+    /**
+     * Test that an update forces a snapshot on the source.
+     */
+    public void testUpdateSnapshot()
+    {
+        try
+        {
+            setupBasicTree();
+            fService.createAVMStore("branch");
+            fService.createBranch(-1, "main:/", "branch:/", "branch");
+            // Modify some things in the branch.
+            fService.createFile("branch:/branch/a/b", "fing").close();
+            fService.getFileOutputStream("branch:/branch/a/b/c/foo").close();
+            fService.removeNode("branch:/branch/a/b/c", "bar");
+            List<AVMDifference> diffs =
+                fSyncService.compare(-1, "branch:/branch", -1, "main:/");
+            assertEquals(3, diffs.size());
+            // Now update.
+            fSyncService.update(diffs, false, false, false, false);
+            diffs = fSyncService.compare(-1, "branch:/branch", -1, "main:/");
+            assertEquals(0, diffs.size());
+            fService.getFileOutputStream("branch:/branch/a/b/fing").close();
+            assertTrue(fService.lookup(-1, "branch:/branch/a/b/fing").getId() !=
+                       fService.lookup(-1, "main:/a/b/fing").getId());
+        }
+        catch (Exception e)
+        {
+            e.printStackTrace(System.err);
+            fail();
+        }
+    }
+    
+    /**
+     * Test that branching forces a snapshot on the source repository.
+     */
+    public void testBranchSnapshot()
+    {
+        try
+        {
+            setupBasicTree();
+            fService.getFileOutputStream("main:/a/b/c/foo").close();
+            fService.createBranch(-1, "main:/a", "main:/", "abranch");
+            assertEquals(fService.lookup(-1, "main:/a/b/c/foo").getId(),
+                         fService.lookup(-1, "main:/abranch/b/c/foo").getId());
+            fService.getFileOutputStream("main:/a/b/c/foo").close();
+            assertTrue(fService.lookup(-1, "main:/a/b/c/foo").getId() !=
+                       fService.lookup(-1, "main:/abranch/b/c/foo").getId());
+        }
+        catch (Exception e)
+        {
+            e.printStackTrace(System.err);
+            fail();
+        }
+    }
+    
     /**
      * Test bulk update.
      */

source/java/org/alfresco/repo/avm/AVMStoreImpl.java

@@ -141,7 +141,8 @@ public class AVMStoreImpl implements AVMStore, Serializable
         // If the root isn't new, we can't take a snapshot since nothing has changed.
         if (!fRoot.getIsNew())
         {
-            throw new AVMExistsException("Already snapshotted.");
+            // So we just return the most recent snapshot.
+            return AVMContext.fgInstance.fVersionRootDAO.getMaxVersionID(this);
         }
         // Clear out the new nodes.
         List<AVMNode> newInRep = AVMContext.fgInstance.fAVMNodeDAO.getNewInStore(this);
@@ -150,11 +151,16 @@ public class AVMStoreImpl implements AVMStore, Serializable
             newGuy.setStoreNew(null);
         }
         // Make up a new version record.
+        String user = AVMContext.fgInstance.getAuthenticationComponent().getCurrentUserName();
+        if (user == null)
+        {
+            user = AVMContext.fgInstance.getAuthenticationComponent().getSystemUserName();
+        }
         VersionRoot versionRoot = new VersionRootImpl(this,
                                                       fRoot,
                                                       fNextVersionID,
                                                       System.currentTimeMillis(),
-                                                      "britt");
+                                                      user);
         AVMContext.fgInstance.fVersionRootDAO.save(versionRoot);
         // Increment the version id.
         fNextVersionID++;
@@ -169,6 +175,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public void createDirectory(String path, String name)
     {
         Lookup lPath = lookupDirectory(-1, path, true);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         DirectoryNode dir = (DirectoryNode)lPath.getCurrentNode();
         if (dir.lookupChild(lPath, name, -1, true, false) != null)
         {
@@ -202,6 +212,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
                                        String name)
     {
         Lookup lPath = lookupDirectory(-1, dstPath, true);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         DirectoryNode dir = (DirectoryNode)lPath.getCurrentNode();
         if (dir.lookupChild(lPath, name, -1, true, false) != null)
         {
@@ -236,6 +250,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public OutputStream createFile(String path, String name)
     {
         Lookup lPath = lookupDirectory(-1, path, true);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         DirectoryNode dir = (DirectoryNode)lPath.getCurrentNode();
         if (dir.lookupChild(lPath, name, -1, true, false) != null)
         {
@@ -262,6 +280,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public void createFile(String path, String name, File data)
     {
         Lookup lPath = lookupDirectory(-1, path, true);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         DirectoryNode dir = (DirectoryNode)lPath.getCurrentNode();
         if (dir.lookupChild(lPath, name, -1, true, false) != null)
         {
@@ -288,6 +310,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public void createLayeredFile(String srcPath, String dstPath, String name)
     {
         Lookup lPath = lookupDirectory(-1, dstPath, true);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         DirectoryNode dir = (DirectoryNode)lPath.getCurrentNode();
         if (dir.lookupChild(lPath, name, -1, true, false) != null)
         {
@@ -354,6 +380,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
                                                            boolean includeDeleted)
     {
         Lookup lPath = lookupDirectory(version, path, false);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         DirectoryNode dir = (DirectoryNode)lPath.getCurrentNode();
         Map<String, AVMNode> listing = dir.getListing(lPath, includeDeleted);
         return translateListing(listing, lPath);
@@ -369,6 +399,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
                                                                  boolean includeDeleted)
     {
         Lookup lPath = lookupDirectory(version, path, false);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         DirectoryNode dir = (DirectoryNode)lPath.getCurrentNode();
         if (lPath.isLayered() && dir.getType() != AVMNodeType.LAYERED_DIRECTORY)
         {
@@ -407,6 +441,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public List<String> getDeleted(int version, String path)
     {
         Lookup lPath = lookupDirectory(version, path, false);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         DirectoryNode dir = (DirectoryNode)lPath.getCurrentNode();
         return dir.getDeletedNames();
     }
@@ -443,6 +481,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public void removeNode(String path, String name)
     {
         Lookup lPath = lookupDirectory(-1, path, true);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         DirectoryNode dir = (DirectoryNode)lPath.getCurrentNode();
         if (dir.lookupChild(lPath, name, -1, true, false) == null)
         {
@@ -460,6 +502,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public void uncover(String dirPath, String name)
     {
         Lookup lPath = lookup(-1, dirPath, true, false);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         AVMNode node = lPath.getCurrentNode();
         if (node.getType() != AVMNodeType.LAYERED_DIRECTORY)
         {
@@ -540,7 +586,7 @@ public class AVMStoreImpl implements AVMStore, Serializable
         Lookup result = new Lookup(this, fName);
         if (path.length() == 0)
         {
-            throw new AVMException("Invalid path: " + path);
+            return null;
         }
         while (path.startsWith("/"))
         {
@@ -576,13 +622,13 @@ public class AVMStoreImpl implements AVMStore, Serializable
             AVMNode child = dir.lookupChild(result, pathElements[i], version, write, includeDeleted);
             if (child == null)
             {
-                throw new AVMNotFoundException("Not found: " + pathElements[i]);
+                return null;
             }
             // Every element that is not the last needs to be a directory.
             if (child.getType() != AVMNodeType.PLAIN_DIRECTORY &&
                 child.getType() != AVMNodeType.LAYERED_DIRECTORY)
             {
-                throw new AVMNotFoundException("Not a directory: " + pathElements[i]);
+                return null;
             }
             result.add(child, pathElements[i], write);
             dir = (DirectoryNode)result.getCurrentNode();
@@ -592,7 +638,7 @@ public class AVMStoreImpl implements AVMStore, Serializable
                                         includeDeleted);
         if (child == null)
         {
-            throw new AVMNotFoundException("Not found: " + pathElements[pathElements.length - 1]);
+            return null;
         }
         result.add(child, pathElements[pathElements.length - 1], write);
         return result;
@@ -629,10 +675,14 @@ public class AVMStoreImpl implements AVMStore, Serializable
         // Just do a regular lookup and assert that the last element
         // is a directory.
         Lookup lPath = lookup(version, path, write, false);
+        if (lPath == null)
+        {
+            return null;
+        }
         if (lPath.getCurrentNode().getType() != AVMNodeType.PLAIN_DIRECTORY &&
             lPath.getCurrentNode().getType() != AVMNodeType.LAYERED_DIRECTORY)
         {
-            throw new AVMWrongTypeException("Not a directory: " + path);
+            return null;
         }
         return lPath;
     }
@@ -646,6 +696,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public String getIndirectionPath(int version, String path)
     {
         Lookup lPath = lookup(version, path, false, false);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         AVMNode node = lPath.getCurrentNode();
         if (node.getType() == AVMNodeType.LAYERED_DIRECTORY)
         {
@@ -665,7 +719,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public void makePrimary(String path)
     {
         Lookup lPath = lookupDirectory(-1, path, true);
-//        lPath.acquireLocks();
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         DirectoryNode dir = (DirectoryNode)lPath.getCurrentNode();
         if (!lPath.isLayered())
         {
@@ -683,7 +740,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public void retargetLayeredDirectory(String path, String target)
     {
         Lookup lPath = lookupDirectory(-1, path, true);
-//        lPath.acquireLocks();
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         DirectoryNode dir = (DirectoryNode)lPath.getCurrentNode();
         if (!lPath.isLayered())
         {
@@ -844,6 +904,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public void setOpacity(String path, boolean opacity)
     {
         Lookup lPath = lookup(-1, path, true, false);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         AVMNode node = lPath.getCurrentNode();
         if (!(node instanceof LayeredDirectoryNode))
         {
@@ -863,6 +927,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public void setNodeProperty(String path, QName name, PropertyValue value)
     {
         Lookup lPath = lookup(-1, path, true, false);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         AVMNode node = lPath.getCurrentNode();
         node.setProperty(name, value);
     }
@@ -875,6 +943,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public void setNodeProperties(String path, Map<QName, PropertyValue> properties)
     {
         Lookup lPath = lookup(-1, path, true, false);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         AVMNode node = lPath.getCurrentNode();
         node.setProperties(properties);
     }
@@ -889,6 +961,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public PropertyValue getNodeProperty(int version, String path, QName name)
     {
         Lookup lPath = lookup(version, path, false, false);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         AVMNode node = lPath.getCurrentNode();
         return node.getProperty(name);
     }
@@ -902,6 +978,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public Map<QName, PropertyValue> getNodeProperties(int version, String path)
     {
         Lookup lPath = lookup(version, path, false, false);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         AVMNode node = lPath.getCurrentNode();
         return node.getProperties();
     }
@@ -914,6 +994,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public void deleteNodeProperty(String path, QName name)
     {
         Lookup lPath = lookup(-1, path, true, false);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         AVMNode node = lPath.getCurrentNode();
         node.deleteProperty(name);
     }
@@ -925,6 +1009,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public void deleteNodeProperties(String path)
     {
         Lookup lPath = lookup(-1, path, true, false);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         AVMNode node = lPath.getCurrentNode();
         node.deleteProperties();
     }
@@ -999,6 +1087,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public ContentData getContentDataForRead(int version, String path)
     {
         Lookup lPath = lookup(version, path, false, false);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         AVMNode node = lPath.getCurrentNode();
         if (!(node instanceof FileNode))
         {
@@ -1015,6 +1107,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public ContentData getContentDataForWrite(String path)
     {
         Lookup lPath = lookup(-1, path, true, false);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         AVMNode node = lPath.getCurrentNode();
         if (!(node instanceof FileNode))
         {
@@ -1031,6 +1127,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public void setContentData(String path, ContentData data)
     {
         Lookup lPath = lookup(-1, path, true, false);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         AVMNode node = lPath.getCurrentNode();
         if (!(node instanceof FileNode))
         {
@@ -1047,6 +1147,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public void addAspect(String path, QName aspectName)
     {
         Lookup lPath = lookup(-1, path, true, false);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         AVMNode node = lPath.getCurrentNode();
         if (AVMContext.fgInstance.fAVMAspectNameDAO.exists(node, aspectName))
         {
@@ -1068,6 +1172,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public List<QName> getAspects(int version, String path)
     {
         Lookup lPath = lookup(version, path, false, false);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         AVMNode node = lPath.getCurrentNode();
         List<AVMAspectName> names = 
             AVMContext.fgInstance.fAVMAspectNameDAO.get(node);
@@ -1087,6 +1195,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public void removeAspect(String path, QName aspectName)
     {
         Lookup lPath = lookup(-1, path, true, false);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         AVMNode node = lPath.getCurrentNode();
         AVMContext.fgInstance.fAVMAspectNameDAO.delete(node, aspectName);
         AspectDefinition def = AVMContext.fgInstance.getDictionaryService().getAspect(aspectName);
@@ -1108,6 +1220,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public boolean hasAspect(int version, String path, QName aspectName)
     {
         Lookup lPath = lookup(version, path, false, false);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         AVMNode node = lPath.getCurrentNode();
         return AVMContext.fgInstance.fAVMAspectNameDAO.exists(node, aspectName);
     }
@@ -1120,6 +1236,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public void setACL(String path, DbAccessControlList acl)
     {
         Lookup lPath = lookup(-1, path, true, false);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         AVMNode node = lPath.getCurrentNode();
         node.setAcl(acl);
     }
@@ -1133,6 +1253,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public DbAccessControlList getACL(int version, String path)
     {
         Lookup lPath = lookup(version, path, false, false);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         return lPath.getCurrentNode().getAcl();
     }
     
@@ -1145,6 +1269,10 @@ public class AVMStoreImpl implements AVMStore, Serializable
     public void link(String parentPath, String name, AVMNodeDescriptor toLink)
     {
         Lookup lPath = lookupDirectory(-1, parentPath, true);
+        if (lPath == null)
+        {
+            throw new AVMNotFoundException("Path not found.");
+        }
         DirectoryNode dir = (DirectoryNode)lPath.getCurrentNode();
         dir.link(lPath, name, toLink);
     }

source/java/org/alfresco/repo/avm/AVMSyncServiceImpl.java

@@ -46,6 +46,11 @@ public class AVMSyncServiceImpl implements AVMSyncService
      */
     private AVMService fAVMService;
 
+    /**
+     * The AVMRepository.
+     */
+    private AVMRepository fAVMRepository;
+    
     /**
      * Do nothing constructor.
      */
@@ -54,10 +59,7 @@ public class AVMSyncServiceImpl implements AVMSyncService
     }
 
     /**
-     * Set the AVM Service. For Spring. For now, at least,
+     * Set the AVM Service. For Spring. 
-     * it's important to wire this using the unintercepted AVMServiceImpl,
-     * as AVMServiceImpl uses Runtime Exceptions for handling valid states
-     * that should not cause rollbacks.
      * @param avmService The AVMService reference.
      */
     public void setAvmService(AVMService avmService)
@@ -65,6 +67,11 @@ public class AVMSyncServiceImpl implements AVMSyncService
         fAVMService = avmService;
     }
     
+    public void setAvmRepository(AVMRepository avmRepository)
+    {
+        fAVMRepository = avmRepository;
+    }
+    
     /**
      * Get a difference list between two corresponding node trees.
      * @param srcVersion The version id for the source tree.
@@ -280,7 +287,14 @@ public class AVMSyncServiceImpl implements AVMSyncService
             {
                 throw new AVMSyncException("Malformed AVMDifference.");
             }
-            AVMNodeDescriptor srcDesc = fAVMService.lookup(diff.getSourceVersion(),
+            int colonOff = diff.getSourcePath().indexOf(':');
+            if (colonOff == -1)
+            {
+                throw new AVMBadArgumentException("Invalid path.");
+            }
+            String storeName = diff.getSourcePath().substring(0, colonOff);
+            int version = fAVMService.createSnapshot(storeName);
+            AVMNodeDescriptor srcDesc = fAVMService.lookup(version,
                                                            diff.getSourcePath(), true);
             if (srcDesc == null)
             {
@@ -385,8 +399,6 @@ public class AVMSyncServiceImpl implements AVMSyncService
         fAVMService.link(parentPath, name, toLink);
     }
     
-    // TODO doesn't handle copies from non head nodes.
-    
     /**
      * Recursively copy a node into the given position.
      * @param parentPath The place to put it.
@@ -417,12 +429,12 @@ public class AVMSyncServiceImpl implements AVMSyncService
         // If it's a file or deleted simply link it in.
         if (toCopy.isFile() || toCopy.isDeleted() || toCopy.isPlainDirectory())
         {
-            fAVMService.link(parent, name, toCopy);
+            fAVMRepository.link(parent, name, toCopy);
             return;
         }
         // Otherwise make a directory in the target parent, and recursiveCopy all the source
         // children into it.
-        AVMNodeDescriptor newParentDesc = fAVMService.createDirectory(parent, name);
+        AVMNodeDescriptor newParentDesc = fAVMRepository.createDirectory(parent, name);
         fgLogger.error(newParentDesc);
         Map<String, AVMNodeDescriptor> children = 
             fAVMService.getDirectoryListing(toCopy, true);
@@ -613,14 +625,14 @@ public class AVMSyncServiceImpl implements AVMSyncService
             // We've found an identity so flatten it.
             if (topNode.getId() == bottomNode.getId())
             {
-                fAVMService.flatten(layer, name);
+                fAVMRepository.flatten(layer, name);
             }
             else
             {
                 // Otherwise recursively flatten the children.
                 if (flatten(topNode, bottomNode))
                 {
-                    fAVMService.flatten(layer, name);
+                    fAVMRepository.flatten(layer, name);
                 }
                 else
                 {

source/java/org/alfresco/repo/avm/LayeredDirectoryNodeImpl.java

@@ -25,7 +25,6 @@ import java.util.SortedMap;
 import java.util.TreeMap;
 
 import org.alfresco.service.cmr.avm.AVMBadArgumentException;
-import org.alfresco.service.cmr.avm.AVMCycleException;
 import org.alfresco.service.cmr.avm.AVMException;
 import org.alfresco.service.cmr.avm.AVMExistsException;
 import org.alfresco.service.cmr.avm.AVMNodeDescriptor;
@@ -316,18 +315,14 @@ class LayeredDirectoryNodeImpl extends DirectoryNodeImpl implements LayeredDirec
         }
         else
         {
-            try
+            Lookup lookup = AVMRepository.GetInstance().lookupDirectory(-1, getUnderlying(lPath));
+            if (lookup != null)
             {
-                Lookup lookup = AVMRepository.GetInstance().lookupDirectory(-1, getUnderlying(lPath));
                 DirectoryNode dir = (DirectoryNode)lookup.getCurrentNode();
                 listing = dir.getListing(lookup, includeDeleted);
             }
-            catch (AVMException re)
+            else
             {
-                if (re instanceof AVMCycleException)
-                {
-                    throw re;
-                }
                 // It's OK for an indirection to dangle.
                 listing = new HashMap<String, AVMNode>();
             }
@@ -406,9 +401,9 @@ class LayeredDirectoryNodeImpl extends DirectoryNodeImpl implements LayeredDirec
         // If we are not opaque, get the underlying base listing.
         if (!fOpacity)
         {
-            try
+            Lookup lookup = AVMRepository.GetInstance().lookupDirectory(-1, dir.getIndirection());
+            if (lookup != null)
             {
-                Lookup lookup = AVMRepository.GetInstance().lookupDirectory(-1, dir.getIndirection());
                 DirectoryNode dirNode = (DirectoryNode)lookup.getCurrentNode();
                 Map<String, AVMNode> listing = dirNode.getListing(lookup, includeDeleted);
                 for (String name : listing.keySet())
@@ -418,13 +413,6 @@ class LayeredDirectoryNodeImpl extends DirectoryNodeImpl implements LayeredDirec
                                                                     lookup.getCurrentIndirection()));
                 }
             }
-            catch (AVMException e)
-            {
-                if (e instanceof AVMCycleException)
-                {   
-                    throw e;
-                }
-            }
         }
         List<ChildEntry> children = AVMContext.fgInstance.fChildEntryDAO.getByParent(this);
         for (ChildEntry child : children)
@@ -489,20 +477,16 @@ class LayeredDirectoryNodeImpl extends DirectoryNodeImpl implements LayeredDirec
             return null;
         }
         // Not here so check our indirection.
-        try
+        Lookup lookup = AVMRepository.GetInstance().lookupDirectory(-1, getUnderlying(lPath));
+        if (lookup != null)
         {
-            Lookup lookup = AVMRepository.GetInstance().lookupDirectory(-1, getUnderlying(lPath));
             DirectoryNode dir = (DirectoryNode)lookup.getCurrentNode();
             AVMNode retVal = dir.lookupChild(lookup, name, -1, false, includeDeleted);
             lPath.setFinalStore(lookup.getFinalStore());
             return retVal;
         }
-        catch (AVMException re)
+        else
         {
-            if (re instanceof AVMCycleException)
-            {
-                throw re;
-            }
             return null;
         }
     }
@@ -535,9 +519,9 @@ class LayeredDirectoryNodeImpl extends DirectoryNodeImpl implements LayeredDirec
         {
             return null;
         }
-        try
+        Lookup lookup = AVMRepository.GetInstance().lookupDirectory(-1, mine.getIndirection());
+        if (lookup != null)
         {
-            Lookup lookup = AVMRepository.GetInstance().lookupDirectory(-1, mine.getIndirection());
             DirectoryNode dir = (DirectoryNode)lookup.getCurrentNode();
             AVMNode child = dir.lookupChild(lookup, name, -1, false, includeDeleted);
             if (child == null)
@@ -546,12 +530,8 @@ class LayeredDirectoryNodeImpl extends DirectoryNodeImpl implements LayeredDirec
             }
             return child.getDescriptor(lookup);
         }
-        catch (AVMException e)
+        else
         {
-            if (e instanceof AVMCycleException)
-            {
-                throw e;
-            }
             return null;
         }
     }

source/java/org/alfresco/repo/avm/LayeredFileNodeImpl.java

@@ -79,6 +79,10 @@ class LayeredFileNodeImpl extends FileNodeImpl implements LayeredFileNode
     {
         // LayeredFileNodes are always copied.
         Lookup lookup = AVMRepository.GetInstance().lookup(-1, fIndirection, false);
+        if (lookup == null)
+        {
+            throw new AVMException("Unbacked layered file node.");
+        }
         AVMNode indirect = lookup.getCurrentNode();
         if (indirect.getType() != AVMNodeType.LAYERED_FILE &&
             indirect.getType() != AVMNodeType.PLAIN_FILE)
@@ -250,6 +254,10 @@ class LayeredFileNodeImpl extends FileNodeImpl implements LayeredFileNode
     public ContentData getContentData(Lookup lPath)
     {
         Lookup lookup = lPath.getAVMStore().getAVMRepository().lookup(-1, getIndirection(), false);
+        if (lookup == null)
+        {
+            throw new AVMException("Invalid target.");
+        }
         AVMNode node = lookup.getCurrentNode();
         if (!(node instanceof FileNode))
         {

source/java/org/alfresco/repo/avm/VersionRootDAO.java

@@ -68,4 +68,11 @@ public interface VersionRootDAO
      * @return The highest numbered version.
      */
     public VersionRoot getMaxVersion(AVMStore store);
+    
+    /**
+     * Get the highest numbered id from all the versions in a store.
+     * @param store The store.
+     * @return The highest numbered id.
+     */
+    public Integer getMaxVersionID(AVMStore store);
 }

source/java/org/alfresco/repo/avm/hibernate/VersionRootDAOHibernate.java

@@ -141,4 +141,17 @@ class VersionRootDAOHibernate extends HibernateDaoSupport implements
                                                "(select max(v.versionID) from VersionRootImpl v)");
         return (VersionRoot)query.uniqueResult();
     }
+    
+    /**
+     * Get the highest numbered id from all the versions in a store.
+     * @param store The store.
+     * @return The highest numbered id.
+     */
+    public Integer getMaxVersionID(AVMStore store)
+    {
+        Query query = getSession().createQuery("select max(vr.versionID) from VersionRootImpl vr " + 
+                                               "where vr.avmStore = :store");
+        query.setEntity("store", store);
+        return (Integer)query.uniqueResult();
+    }
 }

source/java/org/alfresco/service/cmr/avm/AVMService.java

@@ -192,15 +192,6 @@ public interface AVMService
      */
     public void createDirectory(String path, String name);
     
-    /**
-     * Create a new directory, in an already copy on written node.
-     * This should only be used if you really know what you're doing.
-     * @param parent The parent node.
-     * @param name The name of the new directory.
-     * @return A descriptor for the newly created directory.
-     */
-    public AVMNodeDescriptor createDirectory(AVMNodeDescriptor parent, String name);
-    
     /**
      * Create a new layered file.
      * @param targetPath The simple absolute path that the new file will point at.
@@ -695,28 +686,6 @@ public interface AVMService
      */
     public void link(String parentPath, String name, AVMNodeDescriptor toLink);
     
-    /**
-     * This is a more dangerous version of link, which assumes
-     * that copy on write has occurred for the parent node. This is
-     * an internal call. Don't use it if you don't know precisely
-     * what you are doing.
-     * @param parent The parent node.
-     * @param name The name to give the child.
-     * @param child The child node to link.
-     */
-    public void link(AVMNodeDescriptor parent, String name, AVMNodeDescriptor child);
-    
-    /**
-     * Flatten a direct child of a layered directory. This does
-     * the equivalent of removing the given child from the directory 
-     * and then doing an uncover. This routine makes many dangerous 
-     * assumptions and is only for use by AVMSyncService. Don't use it
-     * if you don't know precisely what you are doing.
-     * @param lDir The layered directory node.
-     * @param name The name to flatten.
-     */
-    public void flatten(AVMNodeDescriptor lDir, String name);
-    
     /**
      * Force copy on write of a path.
      * @param path The path to force.