[345049] Optimize CDORevisionCache implementations

https://bugs.eclipse.org/bugs/show_bug.cgi?id=345049

8 files changed, 647 insertions, 194 deletions

diff --git a/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/common/revision/CDORevisionUtil.java b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/common/revision/CDORevisionUtil.java
index 08a1a6d9d9..3e38871bd2 100644
--- a/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/common/revision/CDORevisionUtil.java
+++ b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/common/revision/CDORevisionUtil.java
@@ -25,7 +25,9 @@ import org.eclipse.emf.cdo.internal.common.commit.CDOChangeSetImpl;
 import org.eclipse.emf.cdo.internal.common.messages.Messages;
 import org.eclipse.emf.cdo.internal.common.revision.CDOFeatureMapEntryImpl;
 import org.eclipse.emf.cdo.internal.common.revision.CDORevisableImpl;
-import org.eclipse.emf.cdo.internal.common.revision.CDORevisionCacheImpl;
+import org.eclipse.emf.cdo.internal.common.revision.CDORevisionCacheAuditing;
+import org.eclipse.emf.cdo.internal.common.revision.CDORevisionCacheBranching;
+import org.eclipse.emf.cdo.internal.common.revision.CDORevisionCacheNonAuditing;
 import org.eclipse.emf.cdo.internal.common.revision.CDORevisionImpl;
 import org.eclipse.emf.cdo.internal.common.revision.CDORevisionKeyImpl;
 import org.eclipse.emf.cdo.internal.common.revision.CDORevisionManagerImpl;
@@ -61,13 +63,23 @@ public final class CDORevisionUtil
   }
 
   /**
-   * Creates and returns a new memory sensitive revision cache that supports branches.
+   * Creates and returns a new memory sensitive revision cache.
    * 
    * @since 4.0
    */
-  public static CDORevisionCache createRevisionCache()
+  public static CDORevisionCache createRevisionCache(boolean supportingAudits, boolean supportingBranches)
   {
-    return new CDORevisionCacheImpl();
+    if (supportingBranches)
+    {
+      return new CDORevisionCacheBranching();
+    }
+
+    if (supportingAudits)
+    {
+      return new CDORevisionCacheAuditing();
+    }
+
+    return new CDORevisionCacheNonAuditing();
   }
 
   /**
diff --git a/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/internal/common/revision/AbstractCDORevisionCache.java b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/internal/common/revision/AbstractCDORevisionCache.java
new file mode 100644
index 0000000000..df0689cbef
--- /dev/null
+++ b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/internal/common/revision/AbstractCDORevisionCache.java
@@ -0,0 +1,156 @@
+/**
+ * Copyright (c) 2004 - 2011 Eike Stepper (Berlin, Germany) and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *    Eike Stepper - initial API and implementation
+ *    Simon McDuff - bug 201266
+ *    Simon McDuff - bug 230832
+ */
+package org.eclipse.emf.cdo.internal.common.revision;
+
+import org.eclipse.emf.cdo.common.branch.CDOBranch;
+import org.eclipse.emf.cdo.common.id.CDOID;
+import org.eclipse.emf.cdo.common.revision.CDORevision;
+import org.eclipse.emf.cdo.common.revision.CDORevisionKey;
+import org.eclipse.emf.cdo.spi.common.revision.InternalCDORevision;
+import org.eclipse.emf.cdo.spi.common.revision.InternalCDORevisionCache;
+
+import org.eclipse.net4j.util.event.IListener;
+import org.eclipse.net4j.util.ref.ReferenceQueueWorker;
+
+import java.lang.ref.Reference;
+import java.lang.ref.ReferenceQueue;
+import java.lang.ref.SoftReference;
+import java.text.MessageFormat;
+
+/**
+ * @author Eike Stepper
+ */
+public abstract class AbstractCDORevisionCache extends ReferenceQueueWorker<InternalCDORevision> implements
+    InternalCDORevisionCache
+{
+  private static boolean disableGC;
+
+  public AbstractCDORevisionCache()
+  {
+  }
+
+  @Override
+  protected void work(Reference<? extends InternalCDORevision> reference)
+  {
+    CDORevisionKey key = (CDORevisionKey)reference;
+
+    CDOID id = key.getID();
+    CDOBranch branch = key.getBranch();
+    int version = key.getVersion();
+
+    InternalCDORevision revision = (InternalCDORevision)removeRevision(id, branch.getVersion(version));
+    if (revision == null)
+    {
+      // Use revision in eviction event
+      key = revision;
+    }
+
+    IListener[] listeners = getListeners();
+    if (listeners != null)
+    {
+      fireEvent(new EvictionEventImpl(this, key), listeners);
+    }
+  }
+
+  protected Reference<InternalCDORevision> createReference(CDORevision revision)
+  {
+    if (disableGC)
+    {
+      return new CacheStrongReference((InternalCDORevision)revision);
+    }
+
+    return new CacheSoftReference((InternalCDORevision)revision, getQueue());
+  }
+
+  /**
+   * @author Eike Stepper
+   */
+  private static final class CacheSoftReference extends SoftReference<InternalCDORevision> implements CDORevisionKey
+  {
+    private CDOID id;
+
+    private CDOBranch branch;
+
+    private int version;
+
+    public CacheSoftReference(InternalCDORevision revision, ReferenceQueue<InternalCDORevision> queue)
+    {
+      super(revision, queue);
+      id = revision.getID();
+      branch = revision.getBranch();
+      version = revision.getVersion();
+    }
+
+    public CDOID getID()
+    {
+      return id;
+    }
+
+    public CDOBranch getBranch()
+    {
+      return branch;
+    }
+
+    public int getVersion()
+    {
+      return version;
+    }
+
+    @Override
+    public String toString()
+    {
+      return MessageFormat.format("{0}:{1}v{2}", getID(), getBranch().getID(), getVersion());
+    }
+  }
+
+  /**
+   * @author Eike Stepper
+   */
+  private static final class CacheStrongReference extends SoftReference<InternalCDORevision> implements CDORevisionKey
+  {
+    private CDOID id;
+
+    private CDOBranch branch;
+
+    private int version;
+
+    public CacheStrongReference(InternalCDORevision revision)
+    {
+      super(revision);
+      id = revision.getID();
+      branch = revision.getBranch();
+      version = revision.getVersion();
+    }
+
+    public CDOID getID()
+    {
+      return id;
+    }
+
+    public CDOBranch getBranch()
+    {
+      return branch;
+    }
+
+    public int getVersion()
+    {
+      return version;
+    }
+
+    @Override
+    public String toString()
+    {
+      return MessageFormat.format("{0}:{1}v{2}", getID(), getBranch().getID(), getVersion());
+    }
+  }
+}
diff --git a/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/internal/common/revision/CDORevisionCacheImpl.java b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/internal/common/revision/CDORevisionCacheAuditing.java
index fd1b5255ac..839added0a 100644
--- a/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/internal/common/revision/CDORevisionCacheImpl.java
+++ b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/internal/common/revision/CDORevisionCacheAuditing.java
@@ -16,8 +16,6 @@ import org.eclipse.emf.cdo.common.branch.CDOBranch;
 import org.eclipse.emf.cdo.common.branch.CDOBranchPoint;
 import org.eclipse.emf.cdo.common.branch.CDOBranchVersion;
 import org.eclipse.emf.cdo.common.id.CDOID;
-import org.eclipse.emf.cdo.common.id.CDOIDUtil;
-import org.eclipse.emf.cdo.common.revision.CDOIDAndBranch;
 import org.eclipse.emf.cdo.common.revision.CDORevision;
 import org.eclipse.emf.cdo.common.revision.CDORevisionKey;
 import org.eclipse.emf.cdo.internal.common.bundle.OM;
@@ -25,18 +23,11 @@ import org.eclipse.emf.cdo.spi.common.revision.InternalCDORevision;
 import org.eclipse.emf.cdo.spi.common.revision.InternalCDORevisionCache;
 
 import org.eclipse.net4j.util.CheckUtil;
-import org.eclipse.net4j.util.ObjectUtil;
-import org.eclipse.net4j.util.event.IListener;
 import org.eclipse.net4j.util.om.trace.ContextTracer;
-import org.eclipse.net4j.util.ref.KeyedReference;
-import org.eclipse.net4j.util.ref.KeyedSoftReference;
-import org.eclipse.net4j.util.ref.KeyedStrongReference;
-import org.eclipse.net4j.util.ref.ReferenceQueueWorker;
 
 import org.eclipse.emf.ecore.EClass;
 
 import java.lang.ref.Reference;
-import java.text.MessageFormat;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.Iterator;
@@ -48,33 +39,34 @@ import java.util.Map;
 /**
  * @author Eike Stepper
  */
-public class CDORevisionCacheImpl extends ReferenceQueueWorker<InternalCDORevision> implements InternalCDORevisionCache
+public class CDORevisionCacheAuditing extends AbstractCDORevisionCache
 {
-  private static final ContextTracer TRACER = new ContextTracer(OM.DEBUG_REVISION, CDORevisionCacheImpl.class);
+  private static final ContextTracer TRACER = new ContextTracer(OM.DEBUG_REVISION, CDORevisionCacheAuditing.class);
 
-  private static boolean disableGC;
+  protected Map<Object, RevisionList> revisionLists = new HashMap<Object, RevisionList>();
 
-  private Map<CDOIDAndBranch, RevisionList> revisionLists = new HashMap<CDOIDAndBranch, RevisionList>();
-
-  private Map<CDOID, TypeAndRefCounter> typeMap = new HashMap<CDOID, TypeAndRefCounter>();
-
-  public CDORevisionCacheImpl()
+  public CDORevisionCacheAuditing()
   {
   }
 
   public InternalCDORevisionCache instantiate(CDORevision revision)
   {
-    return new CDORevisionCacheImpl();
+    return new CDORevisionCacheAuditing();
   }
 
   public EClass getObjectType(CDOID id)
   {
     synchronized (revisionLists)
     {
-      TypeAndRefCounter typeCounter = typeMap.get(id);
-      if (typeCounter != null)
+      RevisionList revisionList = revisionLists.get(id);
+      if (revisionList != null)
       {
-        return typeCounter.getType();
+        Reference<InternalCDORevision> ref = revisionList.getFirst();
+        InternalCDORevision revision = ref.get();
+        if (revision != null)
+        {
+          return revision.getEClass();
+        }
       }
 
       return null;
@@ -121,12 +113,50 @@ public class CDORevisionCacheImpl extends ReferenceQueueWorker<InternalCDORevisi
     return currentRevisions;
   }
 
+  public Map<CDOBranch, List<CDORevision>> getAllRevisions()
+  {
+    Map<CDOBranch, List<CDORevision>> result = new HashMap<CDOBranch, List<CDORevision>>();
+    synchronized (revisionLists)
+    {
+      for (RevisionList list : revisionLists.values())
+      {
+        list.getAllRevisions(result);
+      }
+    }
+
+    return result;
+  }
+
+  public List<CDORevision> getRevisions(CDOBranchPoint branchPoint)
+  {
+    List<CDORevision> result = new ArrayList<CDORevision>();
+    CDOBranch branch = branchPoint.getBranch();
+    synchronized (revisionLists)
+    {
+      for (Map.Entry<Object, RevisionList> entry : revisionLists.entrySet())
+      {
+        if (isKeyInBranch(entry.getKey(), branch))
+        // if (ObjectUtil.equals(entry.getKey().getBranch(), branch))
+        {
+          RevisionList list = entry.getValue();
+          InternalCDORevision revision = list.getRevision(branchPoint.getTimeStamp());
+          if (revision != null)
+          {
+            result.add(revision);
+          }
+        }
+      }
+    }
+
+    return result;
+  }
+
   public void addRevision(CDORevision revision)
   {
     CheckUtil.checkArg(revision, "revision");
 
     CDOID id = revision.getID();
-    CDOIDAndBranch key = CDOIDUtil.createIDAndBranch(id, revision.getBranch());
+    Object key = createKey(id, revision.getBranch());
 
     synchronized (revisionLists)
     {
@@ -137,23 +167,14 @@ public class CDORevisionCacheImpl extends ReferenceQueueWorker<InternalCDORevisi
         revisionLists.put(key, list);
       }
 
-      InternalCDORevision rev = (InternalCDORevision)revision;
-      list.addRevision(rev, createReference(key, rev));
-
-      TypeAndRefCounter typeCounter = typeMap.get(id);
-      if (typeCounter == null)
-      {
-        typeCounter = new TypeAndRefCounter(revision.getEClass());
-        typeMap.put(id, typeCounter);
-      }
-
-      typeCounter.increase();
+      list.addRevision((InternalCDORevision)revision, createReference(revision));
+      typeRefIncrease(id, revision.getEClass());
     }
   }
 
   public InternalCDORevision removeRevision(CDOID id, CDOBranchVersion branchVersion)
   {
-    CDOIDAndBranch key = CDOIDUtil.createIDAndBranch(id, branchVersion.getBranch());
+    Object key = createKey(id, branchVersion.getBranch());
     synchronized (revisionLists)
     {
       RevisionList list = revisionLists.get(key);
@@ -163,12 +184,7 @@ public class CDORevisionCacheImpl extends ReferenceQueueWorker<InternalCDORevisi
         if (list.isEmpty())
         {
           revisionLists.remove(key);
-
-          TypeAndRefCounter typeCounter = typeMap.get(id);
-          if (typeCounter != null && typeCounter.decreaseAndGet() == 0)
-          {
-            typeMap.remove(id);
-          }
+          typeRefDecrease(id);
 
           if (TRACER.isEnabled())
           {
@@ -186,7 +202,7 @@ public class CDORevisionCacheImpl extends ReferenceQueueWorker<InternalCDORevisi
     synchronized (revisionLists)
     {
       revisionLists.clear();
-      typeMap.clear();
+      typeRefDispose();
     }
   }
 
@@ -199,130 +215,44 @@ public class CDORevisionCacheImpl extends ReferenceQueueWorker<InternalCDORevisi
     }
   }
 
-  public Map<CDOBranch, List<CDORevision>> getAllRevisions()
+  protected void typeRefIncrease(CDOID id, EClass type)
   {
-    Map<CDOBranch, List<CDORevision>> result = new HashMap<CDOBranch, List<CDORevision>>();
-    synchronized (revisionLists)
-    {
-      for (RevisionList list : revisionLists.values())
-      {
-        list.getAllRevisions(result);
-      }
-    }
-
-    return result;
+    // Do nothing
   }
 
-  public List<CDORevision> getRevisions(CDOBranchPoint branchPoint)
+  protected void typeRefDecrease(CDOID id)
   {
-    List<CDORevision> result = new ArrayList<CDORevision>();
-    CDOBranch branch = branchPoint.getBranch();
-    synchronized (revisionLists)
-    {
-      for (Map.Entry<CDOIDAndBranch, RevisionList> entry : revisionLists.entrySet())
-      {
-        if (ObjectUtil.equals(entry.getKey().getBranch(), branch))
-        {
-          RevisionList list = entry.getValue();
-          InternalCDORevision revision = list.getRevision(branchPoint.getTimeStamp());
-          if (revision != null)
-          {
-            result.add(revision);
-          }
-        }
-      }
-    }
-
-    return result;
+    // Do nothing
   }
 
-  @Override
-  protected void work(Reference<? extends InternalCDORevision> reference)
+  protected void typeRefDispose()
   {
-    @SuppressWarnings("unchecked")
-    KeyedReference<CDORevisionKey, InternalCDORevision> keyedRef = (KeyedReference<CDORevisionKey, InternalCDORevision>)reference;
-    CDORevisionKey key = keyedRef.getKey();
-
-    CDOID id = key.getID();
-    CDOBranch branch = key.getBranch();
-    int version = key.getVersion();
-
-    InternalCDORevision revision = removeRevision(id, branch.getVersion(version));
-    if (revision == null)
-    {
-      // Use revision in eviction event
-      key = revision;
-    }
-
-    IListener[] listeners = getListeners();
-    if (listeners != null)
-    {
-      fireEvent(new EvictionEventImpl(this, key), listeners);
-    }
+    // Do nothing
   }
 
-  private KeyedReference<CDORevisionKey, InternalCDORevision> createReference(CDOIDAndBranch idAndBranch,
-      InternalCDORevision revision)
+  protected Object createKey(CDOID id, CDOBranch branch)
   {
-    CDORevisionKey key = new RevisionKey(idAndBranch, revision.getVersion());
-    if (disableGC)
-    {
-      return new KeyedStrongReference<CDORevisionKey, InternalCDORevision>(key, revision);
-    }
-
-    return new KeyedSoftReference<CDORevisionKey, InternalCDORevision>(key, revision, getQueue());
+    return id;
   }
 
-  private RevisionList getRevisionList(CDOID id, CDOBranch branch)
+  protected boolean isKeyInBranch(Object key, CDOBranch branch)
   {
-    CDOIDAndBranch key = CDOIDUtil.createIDAndBranch(id, branch);
-    synchronized (revisionLists)
-    {
-      return revisionLists.get(key);
-    }
+    return true;
   }
 
-  /**
-   * @author Eike Stepper
-   */
-  private static final class RevisionKey implements CDORevisionKey
+  protected RevisionList getRevisionList(CDOID id, CDOBranch branch)
   {
-    private CDOIDAndBranch idAndBranch;
-
-    private int version;
-
-    public RevisionKey(CDOIDAndBranch idAndBranch, int version)
-    {
-      this.idAndBranch = idAndBranch;
-      this.version = version;
-    }
-
-    public CDOID getID()
-    {
-      return idAndBranch.getID();
-    }
-
-    public CDOBranch getBranch()
-    {
-      return idAndBranch.getBranch();
-    }
-
-    public int getVersion()
-    {
-      return version;
-    }
-
-    @Override
-    public String toString()
+    Object key = createKey(id, branch);
+    synchronized (revisionLists)
     {
-      return MessageFormat.format("{0}:{1}v{2}", getID(), getBranch().getID(), getVersion());
+      return revisionLists.get(key);
     }
   }
 
   /**
    * @author Eike Stepper
    */
-  private static final class RevisionList extends LinkedList<KeyedReference<CDORevisionKey, InternalCDORevision>>
+  protected static final class RevisionList extends LinkedList<Reference<InternalCDORevision>>
   {
     private static final long serialVersionUID = 1L;
 
@@ -334,7 +264,7 @@ public class CDORevisionCacheImpl extends ReferenceQueueWorker<InternalCDORevisi
     {
       if (timeStamp == CDORevision.UNSPECIFIED_DATE)
       {
-        KeyedReference<CDORevisionKey, InternalCDORevision> ref = isEmpty() ? null : getFirst();
+        Reference<InternalCDORevision> ref = isEmpty() ? null : getFirst();
         if (ref != null)
         {
           InternalCDORevision revision = ref.get();
@@ -354,9 +284,9 @@ public class CDORevisionCacheImpl extends ReferenceQueueWorker<InternalCDORevisi
         return null;
       }
 
-      for (Iterator<KeyedReference<CDORevisionKey, InternalCDORevision>> it = iterator(); it.hasNext();)
+      for (Iterator<Reference<InternalCDORevision>> it = iterator(); it.hasNext();)
       {
-        KeyedReference<CDORevisionKey, InternalCDORevision> ref = it.next();
+        Reference<InternalCDORevision> ref = it.next();
         InternalCDORevision revision = ref.get();
         if (revision != null)
         {
@@ -383,9 +313,9 @@ public class CDORevisionCacheImpl extends ReferenceQueueWorker<InternalCDORevisi
 
     public synchronized InternalCDORevision getRevisionByVersion(int version)
     {
-      for (Iterator<KeyedReference<CDORevisionKey, InternalCDORevision>> it = iterator(); it.hasNext();)
+      for (Iterator<Reference<InternalCDORevision>> it = iterator(); it.hasNext();)
       {
-        KeyedReference<CDORevisionKey, InternalCDORevision> ref = it.next();
+        Reference<InternalCDORevision> ref = it.next();
         InternalCDORevision revision = ref.get();
         if (revision != null)
         {
@@ -408,17 +338,16 @@ public class CDORevisionCacheImpl extends ReferenceQueueWorker<InternalCDORevisi
       return null;
     }
 
-    public synchronized boolean addRevision(InternalCDORevision revision,
-        KeyedReference<CDORevisionKey, InternalCDORevision> reference)
+    public synchronized boolean addRevision(InternalCDORevision revision, Reference<InternalCDORevision> reference)
     {
       int version = revision.getVersion();
-      for (ListIterator<KeyedReference<CDORevisionKey, InternalCDORevision>> it = listIterator(); it.hasNext();)
+      for (ListIterator<Reference<InternalCDORevision>> it = listIterator(); it.hasNext();)
       {
-        KeyedReference<CDORevisionKey, InternalCDORevision> ref = it.next();
+        Reference<InternalCDORevision> ref = it.next();
         InternalCDORevision foundRevision = ref.get();
         if (foundRevision != null)
         {
-          CDORevisionKey key = ref.getKey();
+          CDORevisionKey key = (CDORevisionKey)ref;
           int v = key.getVersion();
           if (v == version)
           {
@@ -444,10 +373,10 @@ public class CDORevisionCacheImpl extends ReferenceQueueWorker<InternalCDORevisi
 
     public synchronized void removeRevision(int version)
     {
-      for (Iterator<KeyedReference<CDORevisionKey, InternalCDORevision>> it = iterator(); it.hasNext();)
+      for (Iterator<Reference<InternalCDORevision>> it = iterator(); it.hasNext();)
       {
-        KeyedReference<CDORevisionKey, InternalCDORevision> ref = it.next();
-        CDORevisionKey key = ref.getKey();
+        Reference<InternalCDORevision> ref = it.next();
+        CDORevisionKey key = (CDORevisionKey)ref;
         int v = key.getVersion();
         if (v == version)
         {
@@ -470,9 +399,9 @@ public class CDORevisionCacheImpl extends ReferenceQueueWorker<InternalCDORevisi
     public String toString()
     {
       StringBuffer buffer = new StringBuffer();
-      for (Iterator<KeyedReference<CDORevisionKey, InternalCDORevision>> it = iterator(); it.hasNext();)
+      for (Iterator<Reference<InternalCDORevision>> it = iterator(); it.hasNext();)
       {
-        KeyedReference<CDORevisionKey, InternalCDORevision> ref = it.next();
+        Reference<InternalCDORevision> ref = it.next();
         InternalCDORevision revision = ref.get();
         if (buffer.length() == 0)
         {
@@ -492,9 +421,9 @@ public class CDORevisionCacheImpl extends ReferenceQueueWorker<InternalCDORevisi
 
     public void getAllRevisions(Map<CDOBranch, List<CDORevision>> result)
     {
-      for (Iterator<KeyedReference<CDORevisionKey, InternalCDORevision>> it = iterator(); it.hasNext();)
+      for (Iterator<Reference<InternalCDORevision>> it = iterator(); it.hasNext();)
       {
-        KeyedReference<CDORevisionKey, InternalCDORevision> ref = it.next();
+        Reference<InternalCDORevision> ref = it.next();
         InternalCDORevision revision = ref.get();
         if (revision != null)
         {
@@ -511,34 +440,4 @@ public class CDORevisionCacheImpl extends ReferenceQueueWorker<InternalCDORevisi
       }
     }
   }
-
-  /**
-   * @author Eike Stepper
-   */
-  private static final class TypeAndRefCounter
-  {
-    private EClass type;
-
-    private int refCounter;
-
-    public TypeAndRefCounter(EClass type)
-    {
-      this.type = type;
-    }
-
-    public EClass getType()
-    {
-      return type;
-    }
-
-    public void increase()
-    {
-      ++refCounter;
-    }
-
-    public int decreaseAndGet()
-    {
-      return --refCounter;
-    }
-  }
 }
diff --git a/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/internal/common/revision/CDORevisionCacheBranching.java b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/internal/common/revision/CDORevisionCacheBranching.java
new file mode 100644
index 0000000000..c64f373d15
--- /dev/null
+++ b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/internal/common/revision/CDORevisionCacheBranching.java
@@ -0,0 +1,131 @@
+/**
+ * Copyright (c) 2004 - 2011 Eike Stepper (Berlin, Germany) and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *    Eike Stepper - initial API and implementation
+ *    Simon McDuff - bug 201266
+ *    Simon McDuff - bug 230832
+ */
+package org.eclipse.emf.cdo.internal.common.revision;
+
+import org.eclipse.emf.cdo.common.branch.CDOBranch;
+import org.eclipse.emf.cdo.common.id.CDOID;
+import org.eclipse.emf.cdo.common.id.CDOIDUtil;
+import org.eclipse.emf.cdo.common.revision.CDOIDAndBranch;
+import org.eclipse.emf.cdo.common.revision.CDORevision;
+import org.eclipse.emf.cdo.spi.common.revision.InternalCDORevisionCache;
+
+import org.eclipse.net4j.util.ObjectUtil;
+
+import org.eclipse.emf.ecore.EClass;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * @author Eike Stepper
+ */
+public class CDORevisionCacheBranching extends CDORevisionCacheAuditing
+{
+  private Map<CDOID, TypeAndRefCounter> typeMap = new HashMap<CDOID, TypeAndRefCounter>();
+
+  public CDORevisionCacheBranching()
+  {
+  }
+
+  @Override
+  public InternalCDORevisionCache instantiate(CDORevision revision)
+  {
+    return new CDORevisionCacheBranching();
+  }
+
+  @Override
+  public EClass getObjectType(CDOID id)
+  {
+    synchronized (revisionLists)
+    {
+      TypeAndRefCounter typeCounter = typeMap.get(id);
+      if (typeCounter != null)
+      {
+        return typeCounter.getType();
+      }
+
+      return null;
+    }
+  }
+
+  @Override
+  protected void typeRefIncrease(CDOID id, EClass type)
+  {
+    TypeAndRefCounter typeCounter = typeMap.get(id);
+    if (typeCounter == null)
+    {
+      typeCounter = new TypeAndRefCounter(type);
+      typeMap.put(id, typeCounter);
+    }
+
+    typeCounter.increase();
+  }
+
+  @Override
+  protected void typeRefDecrease(CDOID id)
+  {
+    TypeAndRefCounter typeCounter = typeMap.get(id);
+    if (typeCounter != null && typeCounter.decreaseAndGet() == 0)
+    {
+      typeMap.remove(id);
+    }
+  }
+
+  @Override
+  protected void typeRefDispose()
+  {
+    typeMap.clear();
+  }
+
+  @Override
+  protected boolean isKeyInBranch(Object key, CDOBranch branch)
+  {
+    return ObjectUtil.equals(((CDOIDAndBranch)key).getBranch(), branch);
+  }
+
+  @Override
+  protected Object createKey(CDOID id, CDOBranch branch)
+  {
+    return CDOIDUtil.createIDAndBranch(id, branch);
+  }
+
+  /**
+   * @author Eike Stepper
+   */
+  private static final class TypeAndRefCounter
+  {
+    private EClass type;
+
+    private int refCounter;
+
+    public TypeAndRefCounter(EClass type)
+    {
+      this.type = type;
+    }
+
+    public EClass getType()
+    {
+      return type;
+    }
+
+    public void increase()
+    {
+      ++refCounter;
+    }
+
+    public int decreaseAndGet()
+    {
+      return --refCounter;
+    }
+  }
+}
diff --git a/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/internal/common/revision/CDORevisionCacheNonAuditing.java b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/internal/common/revision/CDORevisionCacheNonAuditing.java
new file mode 100644
index 0000000000..44bdce9c64
--- /dev/null
+++ b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/internal/common/revision/CDORevisionCacheNonAuditing.java
@@ -0,0 +1,216 @@
+/**
+ * Copyright (c) 2004 - 2011 Eike Stepper (Berlin, Germany) and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *    Eike Stepper - initial API and implementation
+ *    Simon McDuff - bug 201266
+ *    Simon McDuff - bug 230832
+ */
+package org.eclipse.emf.cdo.internal.common.revision;
+
+import org.eclipse.emf.cdo.common.branch.CDOBranch;
+import org.eclipse.emf.cdo.common.branch.CDOBranchPoint;
+import org.eclipse.emf.cdo.common.branch.CDOBranchVersion;
+import org.eclipse.emf.cdo.common.id.CDOID;
+import org.eclipse.emf.cdo.common.revision.CDORevision;
+import org.eclipse.emf.cdo.spi.common.revision.InternalCDORevision;
+import org.eclipse.emf.cdo.spi.common.revision.InternalCDORevisionCache;
+
+import org.eclipse.net4j.util.CheckUtil;
+import org.eclipse.net4j.util.ObjectUtil;
+
+import org.eclipse.emf.ecore.EClass;
+
+import java.lang.ref.Reference;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * @author Eike Stepper
+ */
+public class CDORevisionCacheNonAuditing extends AbstractCDORevisionCache
+{
+  private Map<CDOID, Reference<InternalCDORevision>> revisions = new HashMap<CDOID, Reference<InternalCDORevision>>();
+
+  public CDORevisionCacheNonAuditing()
+  {
+  }
+
+  public InternalCDORevisionCache instantiate(CDORevision revision)
+  {
+    return new CDORevisionCacheNonAuditing();
+  }
+
+  public EClass getObjectType(CDOID id)
+  {
+    synchronized (revisions)
+    {
+      Reference<InternalCDORevision> ref = revisions.get(id);
+      if (ref != null)
+      {
+        InternalCDORevision revision = ref.get();
+        if (revision != null)
+        {
+          return revision.getEClass();
+        }
+      }
+
+      return null;
+    }
+  }
+
+  public InternalCDORevision getRevision(CDOID id, CDOBranchPoint branchPoint)
+  {
+    synchronized (revisions)
+    {
+      Reference<InternalCDORevision> ref = revisions.get(id);
+      if (ref != null)
+      {
+        InternalCDORevision revision = ref.get();
+        if (revision != null && revision.isValid(branchPoint))
+        {
+          return revision;
+        }
+      }
+
+      return null;
+    }
+  }
+
+  public InternalCDORevision getRevisionByVersion(CDOID id, CDOBranchVersion branchVersion)
+  {
+    synchronized (revisions)
+    {
+      Reference<InternalCDORevision> ref = revisions.get(id);
+      if (ref != null)
+      {
+        InternalCDORevision revision = ref.get();
+        if (revision != null && revision.getVersion() == branchVersion.getVersion())
+        {
+          return revision;
+        }
+      }
+
+      return null;
+    }
+  }
+
+  public List<CDORevision> getCurrentRevisions()
+  {
+    List<CDORevision> currentRevisions = new ArrayList<CDORevision>();
+    synchronized (revisions)
+    {
+      for (Reference<InternalCDORevision> ref : revisions.values())
+      {
+        InternalCDORevision revision = ref.get();
+        if (revision != null && !revision.isHistorical())
+        {
+          currentRevisions.add(revision);
+        }
+      }
+    }
+
+    return currentRevisions;
+  }
+
+  public Map<CDOBranch, List<CDORevision>> getAllRevisions()
+  {
+    Map<CDOBranch, List<CDORevision>> result = new HashMap<CDOBranch, List<CDORevision>>();
+    synchronized (revisions)
+    {
+      List<CDORevision> list = new ArrayList<CDORevision>();
+      for (Reference<InternalCDORevision> ref : revisions.values())
+      {
+        InternalCDORevision revision = ref.get();
+        if (revision != null)
+        {
+          list.add(revision);
+        }
+      }
+
+      if (!list.isEmpty())
+      {
+        result.put(list.get(0).getBranch(), list);
+      }
+    }
+
+    return result;
+  }
+
+  public List<CDORevision> getRevisions(CDOBranchPoint branchPoint)
+  {
+    List<CDORevision> result = new ArrayList<CDORevision>();
+    synchronized (revisions)
+    {
+      for (Reference<InternalCDORevision> ref : revisions.values())
+      {
+        InternalCDORevision revision = ref.get();
+        if (revision != null && revision.isValid(branchPoint))
+        {
+          result.add(revision);
+        }
+      }
+    }
+
+    return result;
+  }
+
+  public void addRevision(CDORevision revision)
+  {
+    CheckUtil.checkArg(revision, "revision");
+    if (!revision.isHistorical())
+    {
+      synchronized (revisions)
+      {
+        revisions.put(revision.getID(), createReference(revision));
+      }
+    }
+  }
+
+  public InternalCDORevision removeRevision(CDOID id, CDOBranchVersion branchVersion)
+  {
+    synchronized (revisions)
+    {
+      Reference<InternalCDORevision> ref = revisions.get(id);
+      if (ref != null)
+      {
+        InternalCDORevision revision = ref.get();
+        if (revision != null && ObjectUtil.equals(revision.getBranch(), branchVersion.getBranch())
+            && revision.getVersion() == branchVersion.getVersion())
+        {
+          revisions.remove(id);
+          return revision;
+        }
+      }
+      else
+      {
+        revisions.remove(id);
+      }
+    }
+
+    return null;
+  }
+
+  public void clear()
+  {
+    synchronized (revisions)
+    {
+      revisions.clear();
+    }
+  }
+
+  @Override
+  public String toString()
+  {
+    synchronized (revisions)
+    {
+      return revisions.toString();
+    }
+  }
+}
diff --git a/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/internal/common/revision/CDORevisionManagerImpl.java b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/internal/common/revision/CDORevisionManagerImpl.java
index d27681509e..9600474611 100644
--- a/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/internal/common/revision/CDORevisionManagerImpl.java
+++ b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/internal/common/revision/CDORevisionManagerImpl.java
@@ -49,6 +49,8 @@ public class CDORevisionManagerImpl extends Lifecycle implements InternalCDORevi
 {
   private static final ContextTracer TRACER = new ContextTracer(OM.DEBUG_REVISION, CDORevisionManagerImpl.class);
 
+  private boolean supportingAudits;
+
   private boolean supportingBranches;
 
   private RevisionLoader revisionLoader;
@@ -83,6 +85,17 @@ public class CDORevisionManagerImpl extends Lifecycle implements InternalCDORevi
   {
   }
 
+  public boolean isSupportingAudits()
+  {
+    return supportingAudits;
+  }
+
+  public void setSupportingAudits(boolean on)
+  {
+    checkInactive();
+    supportingAudits = on;
+  }
+
   public boolean isSupportingBranches()
   {
     return supportingBranches;
@@ -420,7 +433,7 @@ public class CDORevisionManagerImpl extends Lifecycle implements InternalCDORevi
 
     if (cache == null)
     {
-      cache = (InternalCDORevisionCache)CDORevisionUtil.createRevisionCache();
+      cache = (InternalCDORevisionCache)CDORevisionUtil.createRevisionCache(supportingAudits, supportingBranches);
     }
   }
 
diff --git a/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/spi/common/revision/DelegatingCDORevisionManager.java b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/spi/common/revision/DelegatingCDORevisionManager.java
index 58d1c7b34c..045818a4f4 100644
--- a/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/spi/common/revision/DelegatingCDORevisionManager.java
+++ b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/spi/common/revision/DelegatingCDORevisionManager.java
@@ -77,6 +77,22 @@ public abstract class DelegatingCDORevisionManager extends Lifecycle implements
     getDelegate().setRevisionLocker(revisionLocker);
   }
 
+  /**
+   * @since 4.0
+   */
+  public boolean isSupportingAudits()
+  {
+    return getDelegate().isSupportingAudits();
+  }
+
+  /**
+   * @since 4.0
+   */
+  public void setSupportingAudits(boolean on)
+  {
+    getDelegate().setSupportingAudits(on);
+  }
+
   public boolean isSupportingBranches()
   {
     return getDelegate().isSupportingBranches();
diff --git a/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/spi/common/revision/InternalCDORevisionManager.java b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/spi/common/revision/InternalCDORevisionManager.java
index b20d3ced75..556d46b851 100644
--- a/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/spi/common/revision/InternalCDORevisionManager.java
+++ b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/spi/common/revision/InternalCDORevisionManager.java
@@ -30,6 +30,16 @@ import java.util.List;
  */
 public interface InternalCDORevisionManager extends CDORevisionManager, CDORevisionCacheAdder, ILifecycle
 {
+  /**
+   * @since 4.0
+   */
+  public boolean isSupportingAudits();
+
+  /**
+   * @since 4.0
+   */
+  public void setSupportingAudits(boolean on);
+
   public boolean isSupportingBranches();
 
   public void setSupportingBranches(boolean on);