[477128] Support interactive merging in CDOWorkspace.update()

https://bugs.eclipse.org/bugs/show_bug.cgi?id=477128

21 files changed, 1144 insertions, 217 deletions

diff --git a/features/org.eclipse.emf.cdo.compare-feature/feature.xml b/features/org.eclipse.emf.cdo.compare-feature/feature.xml
index dfce15b70e..421953026a 100644
--- a/features/org.eclipse.emf.cdo.compare-feature/feature.xml
+++ b/features/org.eclipse.emf.cdo.compare-feature/feature.xml
@@ -12,7 +12,7 @@
 <feature
       id="org.eclipse.emf.cdo.compare"
       label="%featureName"
-      version="4.3.0.qualifier"
+      version="4.4.0.qualifier"
       provider-name="%providerName"
       license-feature="org.eclipse.emf.cdo.license"
       license-feature-version="0.0.0">
diff --git a/plugins/org.eclipse.emf.cdo.compare/META-INF/MANIFEST.MF b/plugins/org.eclipse.emf.cdo.compare/META-INF/MANIFEST.MF
index 17860ac5a3..b4a04654bd 100644
--- a/plugins/org.eclipse.emf.cdo.compare/META-INF/MANIFEST.MF
+++ b/plugins/org.eclipse.emf.cdo.compare/META-INF/MANIFEST.MF
@@ -2,7 +2,7 @@ Manifest-Version: 1.0
 Bundle-ManifestVersion: 2
 Bundle-Name: %pluginName
 Bundle-SymbolicName: org.eclipse.emf.cdo.compare; singleton:=true
-Bundle-Version: 4.3.0.qualifier
+Bundle-Version: 4.3.100.qualifier
 Bundle-ClassPath: .
 Bundle-Vendor: %providerName
 Bundle-Localization: plugin
@@ -10,8 +10,8 @@ Bundle-Activator: org.eclipse.emf.cdo.internal.compare.bundle.OM$Activator
 Bundle-RequiredExecutionEnvironment: J2SE-1.5
 Require-Bundle: org.eclipse.emf.cdo;bundle-version="[4.0.0,5.0.0)";visibility:=reexport,
  org.eclipse.emf.compare;bundle-version="[3.0.0,4.0.0)";visibility:=reexport
-Export-Package: org.eclipse.emf.cdo.compare;version="4.3.0",
- org.eclipse.emf.cdo.internal.compare.bundle;version="4.3.0";x-friends:="org.eclipse.emf.cdo.tests"
+Export-Package: org.eclipse.emf.cdo.compare;version="4.3.100",
+ org.eclipse.emf.cdo.internal.compare.bundle;version="4.3.100";x-friends:="org.eclipse.emf.cdo.tests"
 Bundle-ActivationPolicy: lazy
 Import-Package: com.google.common.base;version="[11.0.0,16.0.0)",
  com.google.common.collect;version="[11.0.0,16.0.0)",
diff --git a/plugins/org.eclipse.emf.cdo.explorer.ui/src/org/eclipse/emf/cdo/explorer/ui/handlers/WorkspaceCheckinHandler.java b/plugins/org.eclipse.emf.cdo.explorer.ui/src/org/eclipse/emf/cdo/explorer/ui/handlers/WorkspaceCheckinHandler.java
index 055c49d976..f2fe3183fe 100644
--- a/plugins/org.eclipse.emf.cdo.explorer.ui/src/org/eclipse/emf/cdo/explorer/ui/handlers/WorkspaceCheckinHandler.java
+++ b/plugins/org.eclipse.emf.cdo.explorer.ui/src/org/eclipse/emf/cdo/explorer/ui/handlers/WorkspaceCheckinHandler.java
@@ -11,13 +11,20 @@
 package org.eclipse.emf.cdo.explorer.ui.handlers;
 
 import org.eclipse.emf.cdo.internal.explorer.checkouts.OfflineCDOCheckout;
+import org.eclipse.emf.cdo.util.CommitException;
 import org.eclipse.emf.cdo.workspace.CDOWorkspace;
 
+import org.eclipse.net4j.util.ui.UIUtil;
 import org.eclipse.net4j.util.ui.handlers.AbstractBaseHandler;
 
+import org.eclipse.emf.spi.cdo.InternalCDOTransaction.ChangeSetOutdatedException;
+
 import org.eclipse.core.commands.ExecutionEvent;
 import org.eclipse.core.runtime.IProgressMonitor;
+import org.eclipse.jface.dialogs.MessageDialog;
 import org.eclipse.jface.viewers.ISelection;
+import org.eclipse.swt.widgets.Shell;
+import org.eclipse.ui.handlers.HandlerUtil;
 
 /**
  * @author Eike Stepper
@@ -47,15 +54,53 @@ public class WorkspaceCheckinHandler extends AbstractBaseHandler<OfflineCDOCheck
   }
 
   @Override
-  protected void doExecute(ExecutionEvent event, IProgressMonitor monitor) throws Exception
+  protected void doExecute(final ExecutionEvent event, IProgressMonitor monitor) throws Exception
   {
     OfflineCDOCheckout checkout = elements.get(0);
     CDOWorkspace workspace = checkout.getWorkspace();
     if (workspace != null)
     {
-      // TODO Prompt for checkin comment.
-      // TODO Use progress monitor.
-      workspace.checkin();
+      ChangeSetOutdatedException exception = null;
+
+      try
+      {
+        // TODO Prompt for checkin comment.
+        // TODO Use progress monitor.
+        workspace.checkin();
+      }
+      catch (CommitException ex)
+      {
+        Throwable cause = ex.getCause();
+        if (cause instanceof ChangeSetOutdatedException)
+        {
+          exception = (ChangeSetOutdatedException)cause;
+        }
+        else
+        {
+          throw ex;
+        }
+      }
+      catch (ChangeSetOutdatedException ex)
+      {
+        exception = ex;
+      }
+
+      if (exception != null)
+      {
+        UIUtil.syncExec(new Runnable()
+        {
+          public void run()
+          {
+            Shell shell = HandlerUtil.getActiveShell(event);
+            if (shell == null)
+            {
+              shell = UIUtil.getShell();
+            }
+
+            MessageDialog.openError(shell, "Checkin Error", "Your checkout is outdated and needs to be updated.");
+          }
+        });
+      }
     }
   }
 }
diff --git a/plugins/org.eclipse.emf.cdo.explorer.ui/src/org/eclipse/emf/cdo/explorer/ui/handlers/WorkspaceUpdateHandler.java b/plugins/org.eclipse.emf.cdo.explorer.ui/src/org/eclipse/emf/cdo/explorer/ui/handlers/WorkspaceUpdateHandler.java
index 02a4937cda..dcba37c9ad 100644
--- a/plugins/org.eclipse.emf.cdo.explorer.ui/src/org/eclipse/emf/cdo/explorer/ui/handlers/WorkspaceUpdateHandler.java
+++ b/plugins/org.eclipse.emf.cdo.explorer.ui/src/org/eclipse/emf/cdo/explorer/ui/handlers/WorkspaceUpdateHandler.java
@@ -10,11 +10,21 @@
  */
 package org.eclipse.emf.cdo.explorer.ui.handlers;
 
+import org.eclipse.emf.cdo.common.id.CDOID;
 import org.eclipse.emf.cdo.internal.explorer.checkouts.OfflineCDOCheckout;
-import org.eclipse.emf.cdo.transaction.CDOMerger;
+import org.eclipse.emf.cdo.transaction.CDOCommitContext;
+import org.eclipse.emf.cdo.transaction.CDODefaultTransactionHandler2;
+import org.eclipse.emf.cdo.transaction.CDOMerger.ConflictException;
 import org.eclipse.emf.cdo.transaction.CDOTransaction;
+import org.eclipse.emf.cdo.ui.Support;
+import org.eclipse.emf.cdo.ui.compare.CDOCompareEditorUtil;
+import org.eclipse.emf.cdo.ui.internal.compare.CompareCDOMerger;
+import org.eclipse.emf.cdo.util.CommitException;
+import org.eclipse.emf.cdo.util.ConcurrentAccessException;
+import org.eclipse.emf.cdo.view.CDOView;
 import org.eclipse.emf.cdo.workspace.CDOWorkspace;
 
+import org.eclipse.net4j.util.ui.UIUtil;
 import org.eclipse.net4j.util.ui.handlers.AbstractBaseHandler;
 
 import org.eclipse.emf.spi.cdo.DefaultCDOMerger;
@@ -22,6 +32,8 @@ import org.eclipse.emf.spi.cdo.DefaultCDOMerger;
 import org.eclipse.core.commands.ExecutionEvent;
 import org.eclipse.core.runtime.IProgressMonitor;
 
+import java.util.Set;
+
 /**
  * @author Eike Stepper
  */
@@ -35,16 +47,85 @@ public class WorkspaceUpdateHandler extends AbstractBaseHandler<OfflineCDOChecko
   @Override
   protected void doExecute(ExecutionEvent event, IProgressMonitor monitor) throws Exception
   {
-    OfflineCDOCheckout checkout = elements.get(0);
-    CDOWorkspace workspace = checkout.getWorkspace();
+    final OfflineCDOCheckout checkout = elements.get(0);
+
+    final CDOWorkspace workspace = checkout.getWorkspace();
     if (workspace != null)
     {
-      // TODO Use progress monitor in update().
-      CDOMerger merger = new DefaultCDOMerger.PerFeature.ManyValued();
-      CDOTransaction transaction = workspace.update(merger);
-      transaction.commit(monitor);
-
-      checkout.refresh();
+      try
+      {
+        mergeDefault(checkout, workspace, monitor);
+      }
+      catch (ConflictException ex)
+      {
+        if (Support.COMPARE.isAvailable())
+        {
+          mergeCompare(checkout, workspace);
+        }
+        else
+        {
+          throw ex;
+        }
+      }
     }
   }
+
+  private void mergeCompare(final OfflineCDOCheckout checkout, final CDOWorkspace workspace)
+  {
+    CDOCompareEditorUtil.runWithTitle("Update " + checkout.getLabel(), new Runnable()
+    {
+      public void run()
+      {
+        CDOTransaction transaction = workspace.update(new CompareCDOMerger()
+        {
+          @Override
+          public void merge(CDOTransaction localTransaction, CDOView remoteView, Set<CDOID> affectedIDs)
+              throws ConflictException
+          {
+            remoteView.properties().put(CDOCompareEditorUtil.PROP_COMPARISON_LABEL, "From remote");
+            localTransaction.properties().put(CDOCompareEditorUtil.PROP_COMPARISON_LABEL, "To local");
+
+            super.merge(localTransaction, remoteView, affectedIDs);
+          }
+        });
+
+        transaction.addTransactionHandler(new CDODefaultTransactionHandler2()
+        {
+          @Override
+          public void rolledBackTransaction(CDOTransaction transaction)
+          {
+            closeTransaction(transaction);
+          }
+
+          @Override
+          public void committedTransaction(CDOTransaction transaction, CDOCommitContext commitContext)
+          {
+            checkout.refresh();
+            closeTransaction(transaction);
+          }
+
+          private void closeTransaction(final CDOTransaction transaction)
+          {
+            UIUtil.getDisplay().asyncExec(new Runnable()
+            {
+              public void run()
+              {
+                transaction.close();
+              }
+            });
+          }
+        });
+      }
+    });
+  }
+
+  private void mergeDefault(final OfflineCDOCheckout checkout, final CDOWorkspace workspace, IProgressMonitor monitor)
+      throws ConcurrentAccessException, CommitException
+  {
+    CDOTransaction transaction = workspace.update(new DefaultCDOMerger.PerFeature.ManyValued());
+    transaction.commit(monitor);
+    transaction.close();
+
+    checkout.refresh();
+  }
 }
diff --git a/plugins/org.eclipse.emf.cdo.explorer.ui/src/org/eclipse/emf/cdo/explorer/ui/repositories/wizards/RepositoryClonePage.java b/plugins/org.eclipse.emf.cdo.explorer.ui/src/org/eclipse/emf/cdo/explorer/ui/repositories/wizards/RepositoryClonePage.java
index 66b58c3de2..7e764b05a7 100644
--- a/plugins/org.eclipse.emf.cdo.explorer.ui/src/org/eclipse/emf/cdo/explorer/ui/repositories/wizards/RepositoryClonePage.java
+++ b/plugins/org.eclipse.emf.cdo.explorer.ui/src/org/eclipse/emf/cdo/explorer/ui/repositories/wizards/RepositoryClonePage.java
@@ -75,6 +75,11 @@ public class RepositoryClonePage extends AbstractRepositoryPage
   {
     super.doValidate(properties);
 
+    if (controller == null)
+    {
+      return;
+    }
+
     String connectorDescription = controller.getConnectorDescription();
     if (StringUtil.isEmpty(connectorDescription))
     {
diff --git a/plugins/org.eclipse.emf.cdo.explorer.ui/src/org/eclipse/emf/cdo/explorer/ui/repositories/wizards/RepositoryRemotePage.java b/plugins/org.eclipse.emf.cdo.explorer.ui/src/org/eclipse/emf/cdo/explorer/ui/repositories/wizards/RepositoryRemotePage.java
index f7463ead73..d77e59459e 100644
--- a/plugins/org.eclipse.emf.cdo.explorer.ui/src/org/eclipse/emf/cdo/explorer/ui/repositories/wizards/RepositoryRemotePage.java
+++ b/plugins/org.eclipse.emf.cdo.explorer.ui/src/org/eclipse/emf/cdo/explorer/ui/repositories/wizards/RepositoryRemotePage.java
@@ -16,6 +16,7 @@ import org.eclipse.emf.cdo.explorer.ui.checkouts.wizards.CheckoutWizardPage.Vali
 import org.eclipse.emf.cdo.internal.explorer.repositories.RemoteCDORepository;
 
 import org.eclipse.net4j.util.StringUtil;
+import org.eclipse.net4j.util.ui.UIUtil;
 
 import org.eclipse.swt.widgets.Composite;
 
@@ -44,7 +45,21 @@ public class RepositoryRemotePage extends AbstractRepositoryPage
       protected void validateController()
       {
         super.validateController();
-        validate();
+
+        if (controller != null)
+        {
+          validate();
+        }
+        else
+        {
+          UIUtil.getDisplay().asyncExec(new Runnable()
+          {
+            public void run()
+            {
+              validate();
+            }
+          });
+        }
       }
     };
   }
diff --git a/plugins/org.eclipse.emf.cdo.tests/META-INF/MANIFEST.MF b/plugins/org.eclipse.emf.cdo.tests/META-INF/MANIFEST.MF
index 3e0f2ff4cd..84ee8f906e 100644
--- a/plugins/org.eclipse.emf.cdo.tests/META-INF/MANIFEST.MF
+++ b/plugins/org.eclipse.emf.cdo.tests/META-INF/MANIFEST.MF
@@ -36,7 +36,7 @@ Require-Bundle: org.eclipse.net4j.tests;bundle-version="[4.0.0,5.0.0)";visibilit
  org.eclipse.emf.cdo.server.admin;bundle-version="[4.1.0,5.0.0)";visibility:=reexport,
  org.eclipse.gmf.runtime.notation;bundle-version="[1.5.0,2.0.0)";visibility:=reexport,
  org.eclipse.ocl.ecore;bundle-version="[3.0.0,4.0.0)",
- org.apache.log4j;bundle-version="[1.2.15,1.3.0)",
+ org.apache.log4j;bundle-version="[1.2.0,2.0.0)",
  com.google.guava;bundle-version="[10.0.0,20.0.0)"
 Export-Package: base;version="4.0.200",
  base.impl;version="4.0.200",
diff --git a/plugins/org.eclipse.emf.cdo.tests/src/org/eclipse/emf/cdo/tests/WorkspaceTest.java b/plugins/org.eclipse.emf.cdo.tests/src/org/eclipse/emf/cdo/tests/WorkspaceTest.java
index a3dcea5334..39fdd0ced9 100644
--- a/plugins/org.eclipse.emf.cdo.tests/src/org/eclipse/emf/cdo/tests/WorkspaceTest.java
+++ b/plugins/org.eclipse.emf.cdo.tests/src/org/eclipse/emf/cdo/tests/WorkspaceTest.java
@@ -10,22 +10,29 @@
  */
 package org.eclipse.emf.cdo.tests;
 
+import org.eclipse.emf.cdo.CDOObject;
 import org.eclipse.emf.cdo.common.branch.CDOBranch;
 import org.eclipse.emf.cdo.common.branch.CDOBranchPoint;
+import org.eclipse.emf.cdo.common.commit.CDOChangeSet;
 import org.eclipse.emf.cdo.common.commit.CDOChangeSetData;
 import org.eclipse.emf.cdo.common.commit.CDOCommitInfo;
 import org.eclipse.emf.cdo.common.id.CDOID;
 import org.eclipse.emf.cdo.common.revision.CDOAllRevisionsProvider;
 import org.eclipse.emf.cdo.common.revision.CDORevision;
 import org.eclipse.emf.cdo.common.revision.CDORevisionUtil;
+import org.eclipse.emf.cdo.compare.CDOCompareUtil;
+import org.eclipse.emf.cdo.compare.CDOComparisonScope;
 import org.eclipse.emf.cdo.eresource.CDOResource;
+import org.eclipse.emf.cdo.internal.server.mem.MEMStore;
 import org.eclipse.emf.cdo.server.IRepository;
 import org.eclipse.emf.cdo.server.IStore;
 import org.eclipse.emf.cdo.session.CDOSession;
 import org.eclipse.emf.cdo.session.CDOSessionConfiguration;
 import org.eclipse.emf.cdo.session.CDOSessionConfigurationFactory;
+import org.eclipse.emf.cdo.spi.common.revision.InternalCDORevision;
 import org.eclipse.emf.cdo.spi.server.InternalRepository;
 import org.eclipse.emf.cdo.spi.workspace.InternalCDOWorkspace;
+import org.eclipse.emf.cdo.spi.workspace.InternalCDOWorkspaceBase;
 import org.eclipse.emf.cdo.tests.config.IRepositoryConfig;
 import org.eclipse.emf.cdo.tests.config.impl.ConfigTest.Requires;
 import org.eclipse.emf.cdo.tests.config.impl.ConfigTest.Skips;
@@ -35,7 +42,9 @@ import org.eclipse.emf.cdo.tests.model1.Product1;
 import org.eclipse.emf.cdo.tests.model1.SalesOrder;
 import org.eclipse.emf.cdo.tests.model1.VAT;
 import org.eclipse.emf.cdo.tests.util.TestSessionConfiguration;
+import org.eclipse.emf.cdo.transaction.CDOMerger;
 import org.eclipse.emf.cdo.transaction.CDOMerger.ConflictException;
+import org.eclipse.emf.cdo.transaction.CDOMerger2;
 import org.eclipse.emf.cdo.transaction.CDOTransaction;
 import org.eclipse.emf.cdo.util.CDOUtil;
 import org.eclipse.emf.cdo.util.CommitException;
@@ -51,7 +60,14 @@ import org.eclipse.net4j.util.lifecycle.ILifecycle;
 import org.eclipse.net4j.util.lifecycle.LifecycleEventAdapter;
 import org.eclipse.net4j.util.lifecycle.LifecycleUtil;
 
+import org.eclipse.emf.common.util.BasicMonitor;
 import org.eclipse.emf.common.util.EList;
+import org.eclipse.emf.compare.Comparison;
+import org.eclipse.emf.compare.Diff;
+import org.eclipse.emf.compare.merge.BatchMerger;
+import org.eclipse.emf.compare.merge.IBatchMerger;
+import org.eclipse.emf.compare.merge.IMerger;
+import org.eclipse.emf.compare.merge.IMerger.RegistryImpl;
 import org.eclipse.emf.ecore.EObject;
 import org.eclipse.emf.ecore.util.EcoreUtil;
 import org.eclipse.emf.spi.cdo.DefaultCDOMerger;
@@ -63,6 +79,7 @@ import java.util.ArrayList;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
 /**
  * @author Eike Stepper
@@ -1262,7 +1279,7 @@ public class WorkspaceTest extends AbstractCDOTest
     local.commit();
     local.close();
 
-    DefaultCDOMerger.PerFeature.ManyValued merger = new DefaultCDOMerger.PerFeature.ManyValued();
+    DefaultCDOMerger merger = new DefaultCDOMerger.PerFeature.ManyValued();
     local = workspace.update(merger);
     assertEquals(0, merger.getConflicts().size());
     assertEquals(false, local.isDirty());
@@ -1274,7 +1291,7 @@ public class WorkspaceTest extends AbstractCDOTest
     assertEquals(1, countModifiedProduct(view));
   }
 
-  public void testConflictMasterAndLocalModify() throws Exception
+  public void testConflictMasterAndLocalModify_DefaultMerger() throws Exception
   {
     CDOID id = CDOUtil.getCDOObject(products.get(1)).cdoID();
 
@@ -1289,7 +1306,7 @@ public class WorkspaceTest extends AbstractCDOTest
     local.commit();
     local.close();
 
-    DefaultCDOMerger.PerFeature.ManyValued merger = new DefaultCDOMerger.PerFeature.ManyValued();
+    DefaultCDOMerger merger = new DefaultCDOMerger.PerFeature.ManyValued();
 
     try
     {
@@ -1310,6 +1327,149 @@ public class WorkspaceTest extends AbstractCDOTest
     assertEquals(1, countModifiedProduct(view));
   }
 
+  public void testConflictMasterAndLocalModify_CompareMerger() throws Exception
+  {
+    disableLog4j();
+
+    @SuppressWarnings("unused")
+    CDOID id = CDOUtil.getCDOObject(products.get(1)).cdoID();
+
+    InternalCDOWorkspace workspace = checkout("MAIN", CDOBranchPoint.UNSPECIFIED_DATE);
+    assertNotSame(CDOBranchPoint.UNSPECIFIED_DATE, workspace.getTimeStamp());
+
+    @SuppressWarnings("unused")
+    InternalCDOWorkspaceBase base = workspace.getBase();
+
+    assertEquals(1, modifyProduct(transaction, 1, "MODIFIED_1_"));
+    transaction.commit();
+
+    CDOTransaction local = workspace.openTransaction();
+    assertEquals(1, modifyProduct(local, 1, "MODIFIED_2_"));
+    local.commit();
+
+    local.close();
+
+    CDOMerger merger = new CDOMerger2()
+    {
+      @Deprecated
+      public CDOChangeSetData merge(CDOChangeSet target, CDOChangeSet source) throws UnsupportedOperationException
+      {
+        throw new UnsupportedOperationException();
+      }
+
+      public void merge(CDOTransaction localTransaction, CDOView remoteView, Set<CDOID> affectedIDs)
+          throws ConflictException
+      {
+        CDOComparisonScope scope = new CDOComparisonScope.Minimal(remoteView, localTransaction, null, affectedIDs);
+        Comparison comparison = CDOCompareUtil.compare(scope);
+        EList<Diff> differences = comparison.getDifferences();
+
+        IMerger.Registry mergerRegistry = RegistryImpl.createStandaloneInstance();
+
+        IBatchMerger merger = new BatchMerger(mergerRegistry);
+        merger.copyAllLeftToRight(differences, new BasicMonitor());
+      }
+    };
+
+    local = workspace.update(merger);
+
+    List<CDORevision> dirtyRevisions = getDirtyRevisions(local);
+    dump("dirtyRevisions", dirtyRevisions);
+
+    List<CDORevision> storeRevisions = getStoreRevisions(workspace, dirtyRevisions);
+    dump("storeRevisions", storeRevisions);
+
+    List<CDORevision> baseRevisions = getBaseRevisions(workspace);
+    dump("baseRevisions", baseRevisions);
+
+    dump("COMMIT", null);
+    local.commit();
+
+    dirtyRevisions = getDirtyRevisions(local);
+    dump("dirtyRevisions", dirtyRevisions);
+
+    storeRevisions = getStoreRevisions(workspace, dirtyRevisions);
+    dump("storeRevisions", storeRevisions);
+
+    baseRevisions = getBaseRevisions(workspace);
+    dump("baseRevisions", baseRevisions);
+
+    local.close();
+
+    CDOCommitInfo commitInfo = workspace.checkin();
+    System.out.println(commitInfo);
+  }
+
+  private void dump(String label, List<CDORevision> revisions)
+  {
+    System.out.println();
+    System.out.println(label);
+
+    if (revisions != null)
+    {
+      for (CDORevision revision : revisions)
+      {
+        System.out.println("   " + revision);
+      }
+    }
+  }
+
+  private boolean containsID(List<CDORevision> revisions, CDOID id)
+  {
+    for (CDORevision revision : revisions)
+    {
+      if (revision.getID() == id)
+      {
+        return true;
+      }
+    }
+
+    return false;
+  }
+
+  private List<CDORevision> getDirtyRevisions(CDOTransaction transaction)
+  {
+    List<CDORevision> revisions = new ArrayList<CDORevision>();
+
+    for (CDOObject dirtyObject : transaction.getDirtyObjects().values())
+    {
+      CDORevision revision = dirtyObject.cdoRevision(false);
+      revisions.add(revision);
+    }
+
+    return revisions;
+  }
+
+  private List<CDORevision> getStoreRevisions(InternalCDOWorkspace workspace, List<CDORevision> dirtyRevisions)
+  {
+    List<CDORevision> revisions = new ArrayList<CDORevision>();
+
+    MEMStore store = (MEMStore)workspace.getLocalRepository().getStore();
+    for (InternalCDORevision revision : store.getCurrentRevisions())
+    {
+      if (containsID(dirtyRevisions, revision.getID()))
+      {
+        revisions.add(revision);
+      }
+    }
+
+    return revisions;
+  }
+
+  private List<CDORevision> getBaseRevisions(InternalCDOWorkspace workspace)
+  {
+    List<CDORevision> revisions = new ArrayList<CDORevision>();
+
+    InternalCDOWorkspaceBase base = workspace.getBase();
+    for (CDOID id : base.getIDs())
+    {
+      CDORevision revision = base.getRevision(id);
+      revisions.add(revision);
+    }
+
+    return revisions;
+  }
+
   public void testRevertNoTransaction() throws Exception
   {
     // Checkout local
diff --git a/plugins/org.eclipse.emf.cdo.ui.compare/.settings/.api_filters b/plugins/org.eclipse.emf.cdo.ui.compare/.settings/.api_filters
index 975cf4695c..8a9fd7f22a 100644
--- a/plugins/org.eclipse.emf.cdo.ui.compare/.settings/.api_filters
+++ b/plugins/org.eclipse.emf.cdo.ui.compare/.settings/.api_filters
@@ -8,4 +8,12 @@
             </message_arguments>
         </filter>
     </resource>
+    <resource path="src/org/eclipse/emf/cdo/ui/compare/CDOCompareEditorUtil.java" type="org.eclipse.emf.cdo.ui.compare.CDOCompareEditorUtil$Input">
+        <filter id="576720909">
+            <message_arguments>
+                <message_argument value="ComparisonEditorInput"/>
+                <message_argument value="Input"/>
+            </message_arguments>
+        </filter>
+    </resource>
 </component>
diff --git a/plugins/org.eclipse.emf.cdo.ui.compare/META-INF/MANIFEST.MF b/plugins/org.eclipse.emf.cdo.ui.compare/META-INF/MANIFEST.MF
index 072254f847..6eb82f3240 100644
--- a/plugins/org.eclipse.emf.cdo.ui.compare/META-INF/MANIFEST.MF
+++ b/plugins/org.eclipse.emf.cdo.ui.compare/META-INF/MANIFEST.MF
@@ -2,7 +2,7 @@ Manifest-Version: 1.0
 Bundle-ManifestVersion: 2
 Bundle-Name: %pluginName
 Bundle-SymbolicName: org.eclipse.emf.cdo.ui.compare;singleton:=true
-Bundle-Version: 4.3.0.qualifier
+Bundle-Version: 4.4.0.qualifier
 Bundle-Activator: org.eclipse.emf.cdo.ui.internal.compare.bundle.OM$Activator
 Bundle-Vendor: %providerName
 Bundle-ClassPath: .
@@ -16,6 +16,10 @@ Require-Bundle: org.eclipse.core.runtime;bundle-version="[3.5.0,4.0.0)",
  org.eclipse.emf.cdo.compare;bundle-version="[4.2.0,5.0.0)";visibility:=reexport,
  org.eclipse.emf.compare.ide.ui;bundle-version="[3.0.0,5.0.0)",
  org.eclipse.emf.compare.edit;bundle-version="[3.0.0,5.0.0)"
-Export-Package: org.eclipse.emf.cdo.ui.compare;version="4.3.0",
- org.eclipse.emf.cdo.ui.internal.compare;version="4.3.0";x-internal:=true,
- org.eclipse.emf.cdo.ui.internal.compare.bundle;version="4.3.0";x-internal:=true
+Import-Package: com.google.common.base;version="[11.0.0,16.0.0)",
+ com.google.common.collect;version="[11.0.0,16.0.0)",
+ com.google.common.cache;version="[11.0.0,16.0.0)",
+ com.google.common.util.concurrent;version="[11.0.0,16.0.0)"
+Export-Package: org.eclipse.emf.cdo.ui.compare;version="4.4.0",
+ org.eclipse.emf.cdo.ui.internal.compare;version="4.4.0";x-friends:="org.eclipse.emf.cdo.explorer.ui",
+ org.eclipse.emf.cdo.ui.internal.compare.bundle;version="4.4.0";x-internal:=true
diff --git a/plugins/org.eclipse.emf.cdo.ui.compare/src/org/eclipse/emf/cdo/ui/compare/CDOCompareEditorUtil.java b/plugins/org.eclipse.emf.cdo.ui.compare/src/org/eclipse/emf/cdo/ui/compare/CDOCompareEditorUtil.java
index 17b782a0b1..2a4873be75 100644
--- a/plugins/org.eclipse.emf.cdo.ui.compare/src/org/eclipse/emf/cdo/ui/compare/CDOCompareEditorUtil.java
+++ b/plugins/org.eclipse.emf.cdo.ui.compare/src/org/eclipse/emf/cdo/ui/compare/CDOCompareEditorUtil.java
@@ -18,9 +18,11 @@ import org.eclipse.emf.cdo.common.id.CDOID;
 import org.eclipse.emf.cdo.common.revision.delta.CDORevisionDelta;
 import org.eclipse.emf.cdo.compare.CDOCompare;
 import org.eclipse.emf.cdo.compare.CDOCompareUtil;
+import org.eclipse.emf.cdo.compare.CDOComparisonScope;
 import org.eclipse.emf.cdo.session.CDORepositoryInfo;
 import org.eclipse.emf.cdo.session.CDOSession;
 import org.eclipse.emf.cdo.spi.common.branch.CDOBranchUtil;
+import org.eclipse.emf.cdo.spi.common.revision.CDOIDMapper;
 import org.eclipse.emf.cdo.spi.common.revision.InternalCDORevision;
 import org.eclipse.emf.cdo.spi.common.revision.InternalCDORevisionDelta;
 import org.eclipse.emf.cdo.transaction.CDOTransaction;
@@ -32,6 +34,7 @@ import org.eclipse.emf.cdo.view.CDOView;
 import org.eclipse.emf.cdo.view.CDOViewOpener;
 
 import org.eclipse.net4j.util.lifecycle.LifecycleUtil;
+import org.eclipse.net4j.util.registry.IRegistry;
 import org.eclipse.net4j.util.ui.UIUtil;
 
 import org.eclipse.emf.common.notify.AdapterFactory;
@@ -64,8 +67,10 @@ import org.eclipse.swt.widgets.Shell;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
 /**
  * Static methods to open an EMF Compare dialog.
@@ -75,6 +80,18 @@ import java.util.Map;
  */
 public class CDOCompareEditorUtil
 {
+  /**
+   * @since 4.4
+   */
+  public static final String PROP_COMPARISON_LABEL = "comparison.label";
+
+  /**
+   * @since 4.4
+   */
+  public static final String PROP_COMPARISON_IMAGE = "comparison.image";
+
+  private static final ThreadLocal<String> COMPARISON_TITLE = new ThreadLocal<String>();
+
   private static final ThreadLocal<Boolean> ACTIVATE_EDITOR = new ThreadLocal<Boolean>();
 
   private static final ThreadLocal<Boolean> SUPPRESS_COMMIT = new ThreadLocal<Boolean>();
@@ -160,6 +177,23 @@ public class CDOCompareEditorUtil
   }
 
   /**
+   * @since 4.4
+   */
+  public static boolean openEditor(CDOView leftView, CDOView rightView, Set<CDOID> affectedIDs, boolean activate)
+  {
+    ACTIVATE_EDITOR.set(activate);
+
+    try
+    {
+      return openDialog(leftView, rightView, affectedIDs);
+    }
+    finally
+    {
+      ACTIVATE_EDITOR.remove();
+    }
+  }
+
+  /**
    * @since 4.3
    */
   public static boolean openDialog(CDOSession session, CDOBranchPoint leftPoint, CDOBranchPoint rightPoint)
@@ -249,11 +283,26 @@ public class CDOCompareEditorUtil
   /**
    * @since 4.3
    */
-  public static boolean openDialog(CDOView leftView, final CDOView rightView, CDOView[] originView,
-      CDOViewOpener viewOpener)
+  public static boolean openDialog(CDOView leftView, CDOView rightView, CDOView[] originView, CDOViewOpener viewOpener)
   {
-    final Input input = createComparisonInput(leftView, rightView, originView, viewOpener);
+    Input input = createComparisonInput(leftView, rightView, originView, viewOpener);
+    return openDialog(input, rightView);
+  }
 
+  /**
+   * @since 4.4
+   */
+  public static boolean openDialog(CDOView leftView, CDOView rightView, Set<CDOID> affectedIDs)
+  {
+    Input input = createComparisonInput(leftView, rightView, affectedIDs);
+    return openDialog(input, rightView);
+  }
+
+  /**
+   * @since 4.4
+   */
+  public static boolean openDialog(final Input input, final CDOView rightView)
+  {
     if (input == null)
     {
       UIUtil.getDisplay().syncExec(new Runnable()
@@ -319,6 +368,24 @@ public class CDOCompareEditorUtil
       CDOViewOpener viewOpener)
   {
     Comparison comparison = CDOCompareUtil.compare(leftView, rightView, originView, viewOpener);
+    return createComparisonInput(leftView, rightView, comparison);
+  }
+
+  /**
+   * @since 4.4
+   */
+  public static Input createComparisonInput(CDOView leftView, CDOView rightView, Set<CDOID> affectedIDs)
+  {
+    CDOComparisonScope scope = new CDOComparisonScope.Minimal(leftView, rightView, null, affectedIDs);
+    Comparison comparison = CDOCompareUtil.compare(scope);
+    return createComparisonInput(leftView, rightView, comparison);
+  }
+
+  /**
+   * @since 4.4
+   */
+  public static Input createComparisonInput(CDOView leftView, CDOView rightView, Comparison comparison)
+  {
     if (comparison.getDifferences().isEmpty())
     {
       return null;
@@ -348,19 +415,54 @@ public class CDOCompareEditorUtil
       }
     };
 
-    Image leftImage = itemProvider.getImage(leftBranchPoint);
-    String leftLabel = itemProvider.getText(leftBranchPoint);
-    Image rightImage = itemProvider.getImage(rightBranchPoint);
-    String rightLabel = itemProvider.getText(rightBranchPoint);
+    IRegistry<String, Object> leftProperties = leftView.properties();
+    Image leftImage = (Image)leftProperties.get(PROP_COMPARISON_IMAGE);
+    if (leftImage == null)
+    {
+      leftImage = itemProvider.getImage(leftBranchPoint);
+    }
+
+    String leftLabel = (String)leftProperties.get(PROP_COMPARISON_LABEL);
+    if (leftLabel == null)
+    {
+      leftLabel = itemProvider.getText(leftBranchPoint);
+    }
+
+    IRegistry<String, Object> rightProperties = rightView.properties();
+    Image rightImage = (Image)rightProperties.get(PROP_COMPARISON_IMAGE);
+    if (rightImage == null)
+    {
+      rightImage = itemProvider.getImage(rightBranchPoint);
+    }
+
+    String rightLabel = (String)rightProperties.get(PROP_COMPARISON_LABEL);
+    if (rightLabel == null)
+    {
+      rightLabel = itemProvider.getText(rightBranchPoint);
+    }
+
     itemProvider.dispose();
 
     boolean leftEditable = !leftView.isReadOnly();
     boolean rightEditable = !rightView.isReadOnly();
-    boolean merge = leftEditable || rightEditable;
-    if (merge)
+
+    String title = COMPARISON_TITLE.get();
+    if (title == null)
     {
-      leftLabel = "From " + leftLabel;
-      rightLabel = "Into " + rightLabel;
+      String repositoryName = ((InternalCDOView)leftView).getRepositoryName();
+
+      boolean merge = leftEditable || rightEditable;
+      if (merge)
+      {
+        title = "Merge " + repositoryName + " from " + leftLabel + " into " + rightLabel;
+
+        leftLabel = "From " + leftLabel;
+        rightLabel = "Into " + rightLabel;
+      }
+      else
+      {
+        title = "Compare " + repositoryName + " between " + leftLabel + " and " + rightLabel;
+      }
     }
 
     CompareConfiguration configuration = new CompareConfiguration();
@@ -371,16 +473,29 @@ public class CDOCompareEditorUtil
     configuration.setRightLabel(rightLabel);
     configuration.setRightEditable(rightEditable);
 
-    String repositoryName = ((InternalCDOView)leftView).getRepositoryName();
-    String title = (merge ? "Merge " : "Compare ") + repositoryName + " " + leftLabel + (merge ? " into " : " and ")
-        + rightLabel;
-
     Input input = new Input(rightView, configuration, comparison, editingDomain, adapterFactory);
     input.setTitle(title);
     return input;
   }
 
   /**
+   * @since 4.4
+   */
+  public static void runWithTitle(String title, Runnable runnable)
+  {
+    COMPARISON_TITLE.set(title);
+
+    try
+    {
+      runnable.run();
+    }
+    finally
+    {
+      COMPARISON_TITLE.remove();
+    }
+  }
+
+  /**
    * @since 4.3
    */
   public static boolean isSuppressCommit()
@@ -486,9 +601,10 @@ public class CDOCompareEditorUtil
 
   /**
    * @author Eike Stepper
+   * @since 4.4
    */
   @SuppressWarnings("restriction")
-  private static final class Input extends org.eclipse.emf.compare.ide.ui.internal.editor.ComparisonEditorInput
+  public static final class Input extends org.eclipse.emf.compare.ide.ui.internal.editor.ComparisonEditorInput
   {
     private static final Image COMPARE_IMAGE = OM.getImage("icons/compare.gif");
 
@@ -554,6 +670,8 @@ public class CDOCompareEditorUtil
           Collection<CDOObject> values = transaction.getNewObjects().values();
           if (!values.isEmpty())
           {
+            Map<CDOID, CDOID> idMappings = new HashMap<CDOID, CDOID>();
+
             CDOObject[] rightObjects = values.toArray(new CDOObject[values.size()]);
             for (CDOObject rightObject : rightObjects)
             {
@@ -563,24 +681,43 @@ public class CDOCompareEditorUtil
                 CDOObject leftObject = CDOUtil.getCDOObject(match.getLeft());
                 CDOID id = leftObject.cdoID();
 
+                idMappings.put(rightObject.cdoID(), id);
                 org.eclipse.emf.internal.cdo.transaction.CDOTransactionImpl.resurrectObject(rightObject, id);
               }
             }
-          }
 
-          try
-          {
-            if (!suppressCommit)
+            if (!idMappings.isEmpty())
             {
-              transaction.commit(monitor);
-              setDirty(false);
+              CDOIDMapper idMapper = new CDOIDMapper(idMappings);
+              // idMapper.setAllowUnmappedTempIDs(true);
+
+              for (CDOObject newObject : values)
+              {
+                InternalCDORevision revision = (InternalCDORevision)newObject.cdoRevision();
+                revision.adjustReferences(idMapper);
+              }
+
+              for (CDOObject dirtyObject : transaction.getDirtyObjects().values())
+              {
+                InternalCDORevision revision = (InternalCDORevision)dirtyObject.cdoRevision();
+                revision.adjustReferences(idMapper);
+              }
             }
           }
-          catch (Exception ex)
+        }
+
+        try
+        {
+          if (!suppressCommit)
           {
-            OM.BUNDLE.coreException(ex);
+            transaction.commit(monitor);
+            setDirty(false);
           }
         }
+        catch (Exception ex)
+        {
+          OM.BUNDLE.coreException(ex);
+        }
       }
     }
 
diff --git a/plugins/org.eclipse.emf.cdo.ui.compare/src/org/eclipse/emf/cdo/ui/internal/compare/CompareCDOMerger.java b/plugins/org.eclipse.emf.cdo.ui.compare/src/org/eclipse/emf/cdo/ui/internal/compare/CompareCDOMerger.java
new file mode 100644
index 0000000000..11f6fcb72e
--- /dev/null
+++ b/plugins/org.eclipse.emf.cdo.ui.compare/src/org/eclipse/emf/cdo/ui/internal/compare/CompareCDOMerger.java
@@ -0,0 +1,111 @@
+/*
+ * Copyright (c) 2015 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
+ */
+package org.eclipse.emf.cdo.ui.internal.compare;
+
+import org.eclipse.emf.cdo.common.commit.CDOChangeSet;
+import org.eclipse.emf.cdo.common.commit.CDOChangeSetData;
+import org.eclipse.emf.cdo.common.id.CDOID;
+import org.eclipse.emf.cdo.transaction.CDOMerger2;
+import org.eclipse.emf.cdo.transaction.CDOTransaction;
+import org.eclipse.emf.cdo.ui.compare.CDOCompareEditorUtil;
+import org.eclipse.emf.cdo.view.CDOView;
+
+import org.eclipse.net4j.util.lifecycle.ILifecycle;
+import org.eclipse.net4j.util.lifecycle.LifecycleEventAdapter;
+import org.eclipse.net4j.util.ui.UIUtil;
+
+import org.eclipse.ui.IEditorPart;
+import org.eclipse.ui.IPartListener;
+import org.eclipse.ui.IWorkbenchPage;
+import org.eclipse.ui.IWorkbenchPart;
+
+import java.util.Set;
+
+/**
+ * @author Eike Stepper
+ */
+public class CompareCDOMerger implements CDOMerger2
+{
+  public CompareCDOMerger()
+  {
+  }
+
+  @Deprecated
+  public CDOChangeSetData merge(CDOChangeSet target, CDOChangeSet source) throws UnsupportedOperationException
+  {
+    throw new UnsupportedOperationException();
+  }
+
+  public void merge(final CDOTransaction localTransaction, CDOView remoteView, Set<CDOID> affectedIDs)
+      throws ConflictException
+  {
+    final IEditorPart[] result = { null };
+
+    final IWorkbenchPage page = UIUtil.getActiveWorkbenchPage();
+    final IPartListener listener = new IPartListener()
+    {
+      @SuppressWarnings("restriction")
+      public void partOpened(IWorkbenchPart part)
+      {
+        if (part instanceof org.eclipse.compare.internal.CompareEditor)
+        {
+          result[0] = (IEditorPart)part;
+        }
+      }
+
+      public void partDeactivated(IWorkbenchPart part)
+      {
+        // Do nothing.
+      }
+
+      public void partClosed(IWorkbenchPart part)
+      {
+        if (part == result[0])
+        {
+          localTransaction.close();
+          page.removePartListener(this);
+        }
+      }
+
+      public void partBroughtToTop(IWorkbenchPart part)
+      {
+        // Do nothing.
+      }
+
+      public void partActivated(IWorkbenchPart part)
+      {
+        // Do nothing.
+      }
+    };
+
+    page.addPartListener(listener);
+
+    localTransaction.addListener(new LifecycleEventAdapter()
+    {
+      @Override
+      protected void onDeactivated(ILifecycle lifecycle)
+      {
+        if (result[0] != null)
+        {
+          UIUtil.getDisplay().asyncExec(new Runnable()
+          {
+            public void run()
+            {
+              page.closeEditor(result[0], false);
+            }
+          });
+        }
+      }
+    });
+
+    CDOCompareEditorUtil.openEditor(remoteView, localTransaction, affectedIDs, true);
+  }
+}
diff --git a/plugins/org.eclipse.emf.cdo.ui.compare/src/org/eclipse/emf/cdo/ui/internal/compare/CompareConflictHandler.java b/plugins/org.eclipse.emf.cdo.ui.compare/src/org/eclipse/emf/cdo/ui/internal/compare/CompareConflictHandler.java
index f052ca9b6a..158bcdd81b 100644
--- a/plugins/org.eclipse.emf.cdo.ui.compare/src/org/eclipse/emf/cdo/ui/internal/compare/CompareConflictHandler.java
+++ b/plugins/org.eclipse.emf.cdo.ui.compare/src/org/eclipse/emf/cdo/ui/internal/compare/CompareConflictHandler.java
@@ -54,7 +54,7 @@ public class CompareConflictHandler implements ConflictHandler
     try
     {
       CDOCompareEditorUtil.setSuppressCommit(true);
-      return CDOCompareEditorUtil.openDialog(remoteView, transaction, null);
+      return CDOCompareEditorUtil.openDialog(remoteView, transaction, (CDOView[])null);
     }
     finally
     {
diff --git a/plugins/org.eclipse.emf.cdo.ui/src/org/eclipse/emf/cdo/ui/CDOLabelDecorator.java b/plugins/org.eclipse.emf.cdo.ui/src/org/eclipse/emf/cdo/ui/CDOLabelDecorator.java
index f1826f0e05..e0f6eab7b4 100644
--- a/plugins/org.eclipse.emf.cdo.ui/src/org/eclipse/emf/cdo/ui/CDOLabelDecorator.java
+++ b/plugins/org.eclipse.emf.cdo.ui/src/org/eclipse/emf/cdo/ui/CDOLabelDecorator.java
@@ -105,7 +105,15 @@ public class CDOLabelDecorator implements ILabelDecorator
 
   public Image decorateImage(Image image, Object element)
   {
-    return decorate(image, element);
+    try
+    {
+      image = decorate(image, element);
+    }
+    catch (RuntimeException ignore)
+    {
+    }
+
+    return image;
   }
 
   public String decorateText(String text, Object element)
diff --git a/plugins/org.eclipse.emf.cdo.workspace/src/org/eclipse/emf/cdo/internal/workspace/CDOWorkspaceImpl.java b/plugins/org.eclipse.emf.cdo.workspace/src/org/eclipse/emf/cdo/internal/workspace/CDOWorkspaceImpl.java
index 5bce99852c..2431874930 100644
--- a/plugins/org.eclipse.emf.cdo.workspace/src/org/eclipse/emf/cdo/internal/workspace/CDOWorkspaceImpl.java
+++ b/plugins/org.eclipse.emf.cdo.workspace/src/org/eclipse/emf/cdo/internal/workspace/CDOWorkspaceImpl.java
@@ -65,6 +65,8 @@ import org.eclipse.emf.cdo.transaction.CDODefaultTransactionHandler1;
 import org.eclipse.emf.cdo.transaction.CDODefaultTransactionHandler2;
 import org.eclipse.emf.cdo.transaction.CDODefaultTransactionHandler3;
 import org.eclipse.emf.cdo.transaction.CDOMerger;
+import org.eclipse.emf.cdo.transaction.CDOMerger.ConflictException;
+import org.eclipse.emf.cdo.transaction.CDOMerger2;
 import org.eclipse.emf.cdo.transaction.CDOTransaction;
 import org.eclipse.emf.cdo.transaction.CDOTransactionFinishedEvent;
 import org.eclipse.emf.cdo.util.CommitException;
@@ -192,8 +194,7 @@ public class CDOWorkspaceImpl extends Notifier implements InternalCDOWorkspace
   protected void checkout()
   {
     final OMMonitor monitor = new Monitor();
-    final IStoreAccessor.Raw accessor = getLocalWriter(null);
-    StoreThreadLocal.setAccessor(accessor);
+    final IStoreAccessor.Raw accessor = beginRawAccess(null);
 
     try
     {
@@ -526,151 +527,218 @@ public class CDOWorkspaceImpl extends Notifier implements InternalCDOWorkspace
         timeStamp = remoteSession.getLastUpdateTime();
       }
 
-      final long newTimeStamp = timeStamp;
+      long newTimeStamp = timeStamp;
 
-      final InternalCDOBranchManager branchManager = remoteSession.getBranchManager();
-      final CDOBranchPoint basePoint = branchManager.getBranch(this.branchPath).getPoint(this.timeStamp);
-      final CDOBranchPoint remotePoint = branchManager.getBranch(branchPath).getPoint(newTimeStamp);
+      InternalCDOBranchManager branchManager = remoteSession.getBranchManager();
+      CDOBranchPoint basePoint = branchManager.getBranch(this.branchPath).getPoint(this.timeStamp);
+      CDOBranchPoint remotePoint = branchManager.getBranch(branchPath).getPoint(newTimeStamp);
+      CDOBranchPointRange range = CDOBranchUtil.createRange(basePoint, remotePoint);
 
-      final CDOBranchPointRange range = CDOBranchUtil.createRange(basePoint, remotePoint);
+      CDOChangeSetData remoteData = remoteSession.getSessionProtocol().loadChangeSets(range)[0];
+      CDOChangeSetData localData = getLocalChanges();
 
-      final CDOChangeSetData remoteData = remoteSession.getSessionProtocol().loadChangeSets(range)[0];
-      final CDOChangeSetData localData = getLocalChanges();
-      final CDOChangeSetData result = getMergeResult(merger, basePoint, remotePoint, localData, remoteData);
+      InternalCDOTransaction transaction;
 
-      final InternalCDOTransaction transaction = (InternalCDOTransaction)getLocalSession().openTransaction();
-      initView(transaction);
+      if (merger instanceof CDOMerger2)
+      {
+        CDOMerger2 merger2 = (CDOMerger2)merger;
+
+        Set<CDOID> affectedIDs = new HashSet<CDOID>();
+        addIDs(affectedIDs, remoteData);
+        addIDs(affectedIDs, localData);
+
+        transaction = openLocalTransaction(remoteSession, remoteData, remotePoint, newTimeStamp);
+
+        InternalCDOBranch remoteBranch = remoteSession.getBranchManager().getBranch(branchPath);
+        CDOView remoteView = remoteSession.openView(remoteBranch);
+
+        merger2.merge(transaction, remoteView, affectedIDs);
+      }
+      else
+      {
+        CDOChangeSetData result = getMergeResult(merger, basePoint, remotePoint, localData, remoteData);
+
+        transaction = openLocalTransaction(remoteSession, remoteData, remotePoint, newTimeStamp);
+        transaction.applyChangeSet(result, new BaseRevisionProvider(), this, null, false);
+      }
+
+      if (saveBranchPoint)
+      {
+        CDOBranch branch = remotePoint.getBranch();
+        branchID = branch.getID();
+        this.branchPath = branch.getPathName();
+        this.timeStamp = timeStamp;
+        saveProperties();
+      }
 
-      transaction.applyChangeSet(result, new BaseRevisionProvider(), this, null, false);
-      transaction.addTransactionHandler(new CDODefaultTransactionHandler3()
+      return transaction;
+    }
+    catch (ConflictException ex)
+    {
+      return handleMergeConflict(ex);
+    }
+    catch (RuntimeException ex)
+    {
+      closeRemoteSession(remoteSession);
+      throw ex;
+    }
+    catch (Error ex)
+    {
+      closeRemoteSession(remoteSession);
+      throw ex;
+    }
+  }
+
+  private InternalCDOTransaction openLocalTransaction(final InternalCDOSession remoteSession,
+      final CDOChangeSetData remoteData, final CDOBranchPoint remotePoint, final long newTimeStamp)
+  {
+    InternalCDOTransaction transaction = (InternalCDOTransaction)getLocalSession().openTransaction();
+    initView(transaction);
+
+    transaction.addTransactionHandler(new CDODefaultTransactionHandler3()
+    {
+      @Override
+      public void committedTransaction(CDOTransaction transaction, CDOCommitContext commitContext, CDOCommitInfo result)
       {
-        @Override
-        public void rolledBackTransaction(CDOTransaction transaction)
+        Set<CDOID> affectedIDs = getAffectedIDs(commitContext, remoteData);
+
+        CDORevisionProvider local = CDOWorkspaceImpl.this;
+        CDORevisionProvider remote = new ManagedRevisionProvider(remoteSession.getRevisionManager(), remotePoint);
+
+        updateBase(local, remote, affectedIDs);
+        setDirtyFromBase();
+        setTimeStamp(newTimeStamp);
+
+        fireEvent(new ObjectStatesChangedEventImpl(CDOWorkspaceImpl.this, affectedIDs));
+      }
+
+      private void updateBase(CDORevisionProvider local, CDORevisionProvider remote, Set<CDOID> affectedIDs)
+      {
+        IStoreAccessor.Raw accessor = null;
+
+        try
         {
-          closeRemoteSession(remoteSession);
+          for (CDOID id : affectedIDs)
+          {
+            InternalCDORevision localRevision = getRevision(id, local);
+            InternalCDORevision remoteRevision = getRevision(id, remote);
+            accessor = updateBase(localRevision, remoteRevision, id, accessor);
+          }
         }
+        finally
+        {
+          finishRawAccess(accessor);
+        }
+      }
 
-        @Override
-        public void committedTransaction(CDOTransaction transaction, CDOCommitContext commitContext,
-            CDOCommitInfo result)
+      private IStoreAccessor.Raw updateBase(InternalCDORevision localRevision, InternalCDORevision remoteRevision,
+          CDOID id, IStoreAccessor.Raw accessor)
+      {
+        if (localRevision == null)
         {
-          try
+          if (remoteRevision == null)
           {
-            Set<CDOID> affectedIDs = getAffectedIDs(commitContext, remoteData);
-
-            CDORevisionProvider local = CDOWorkspaceImpl.this;
-            CDORevisionProvider remote = new ManagedRevisionProvider(remoteSession.getRevisionManager(), remotePoint);
-
-            updateBase(affectedIDs, local, remote);
-            setTimeStamp(newTimeStamp);
-
-            fireEvent(new ObjectStatesChangedEventImpl(CDOWorkspaceImpl.this, affectedIDs));
+            // Unchanged
+            base.deregisterObject(id);
           }
-          finally
+          else
           {
-            closeRemoteSession(remoteSession);
+            // Detached
+            InternalCDORevision baseRevision = remoteRevision.copy();
+            baseRevision.setBranchPoint(localSessionHead);
+
+            base.registerChangedOrDetachedObject(baseRevision);
           }
         }
-
-        private void updateBase(Set<CDOID> affectedIDs, CDORevisionProvider local, CDORevisionProvider remote)
+        else
         {
-          for (CDOID id : affectedIDs)
+          if (remoteRevision == null)
+          {
+            // Added
+            base.registerAddedObject(id);
+          }
+          else
           {
-            CDORevision localRevision = getRevision(id, local);
-            CDORevision remoteRevision = getRevision(id, remote);
-            if (localRevision == null)
+            InternalCDORevision baseRevision = null;
+            if (localRevision.getVersion() != remoteRevision.getVersion())
             {
-              if (remoteRevision == null)
-              {
-                // Unchanged
-                base.deregisterObject(id);
-              }
-              else
-              {
-                // Detached
-                InternalCDORevision baseRevision = ((InternalCDORevision)remoteRevision).copy();
-                baseRevision.setBranchPoint(localSessionHead);
+              baseRevision = (InternalCDORevision)base.getRevision(id);
+            }
 
-                base.registerChangedOrDetachedObject(baseRevision);
-              }
+            // Unchanged
+            base.deregisterObject(id);
+
+            CDORevisionDelta delta = localRevision.compare(remoteRevision);
+            if (!delta.isEmpty())
+            {
+              // Changed
+              baseRevision = remoteRevision.copy();
+              baseRevision.setBranchPoint(localSessionHead);
+
+              base.registerChangedOrDetachedObject(baseRevision);
             }
-            else
+            else if (baseRevision != null)
             {
-              if (remoteRevision == null)
-              {
-                // Added
-                base.registerAddedObject(id);
-              }
-              else
+              // If the delta is empty but multiple local revisions exist replace them all by the remote revision.
+              // This compensates the missing checkin post processing as there is no base revision anymore.
+              accessor = beginRawAccess(accessor);
+
+              int version = Math.abs(localRevision.getVersion());
+              CDOBranch branch = localRevision.getBranch();
+              EClass eClass = localRevision.getEClass();
+
+              for (int v = baseRevision.getVersion(); v <= version; v++)
               {
-                // Unchanged
-                base.deregisterObject(id);
-
-                CDORevisionDelta delta = localRevision.compare(remoteRevision);
-                if (!delta.isEmpty())
-                {
-                  // Changed
-                  InternalCDORevision baseRevision = ((InternalCDORevision)remoteRevision).copy();
-                  baseRevision.setBranchPoint(localSessionHead);
-
-                  base.registerChangedOrDetachedObject(baseRevision);
-                }
+                accessor.rawDelete(id, v, branch, eClass, new Monitor());
               }
+
+              localRevision = remoteRevision.copy();
+              localRevision.setBranchPoint(localSessionHead);
+
+              accessor.rawStore(localRevision, new Monitor());
             }
           }
         }
 
-        private Set<CDOID> getAffectedIDs(CDOCommitContext commitContext, final CDOChangeSetData remoteData)
-        {
-          Set<CDOID> affectedIDs = new HashSet<CDOID>();
-
-          // Base IDs
-          affectedIDs.addAll(base.getIDs());
-
-          // Remote IDs
-          affectedIDs.addAll(remoteData.getChangeKinds().keySet());
-
-          // Local IDs
-          affectedIDs.addAll(commitContext.getNewObjects().keySet());
-          affectedIDs.addAll(commitContext.getDirtyObjects().keySet());
-          affectedIDs.addAll(commitContext.getDetachedObjects().keySet());
+        return accessor;
+      }
 
-          return affectedIDs;
-        }
+      private Set<CDOID> getAffectedIDs(CDOCommitContext commitContext, final CDOChangeSetData remoteData)
+      {
+        Set<CDOID> affectedIDs = new HashSet<CDOID>();
+        addIDs(affectedIDs, base.getIDs()); // Base IDs
+        addIDs(affectedIDs, remoteData.getChangeKinds()); // Remote IDs
+        addIDs(affectedIDs, commitContext); // Local IDs
+        return affectedIDs;
+      }
 
-        private CDORevision getRevision(CDOID id, CDORevisionProvider revisionProvider)
+      private InternalCDORevision getRevision(CDOID id, CDORevisionProvider revisionProvider)
+      {
+        CDORevision revision = revisionProvider.getRevision(id);
+        if (revision instanceof DetachedCDORevision)
         {
-          CDORevision revision = revisionProvider.getRevision(id);
-          if (revision instanceof DetachedCDORevision)
-          {
-            revision = null;
-          }
-
-          return revision;
+          revision = null;
         }
-      });
 
-      if (saveBranchPoint)
-      {
-        CDOBranch branch = remotePoint.getBranch();
-        branchID = branch.getID();
-        this.branchPath = branch.getPathName();
-        this.timeStamp = timeStamp;
-        saveProperties();
+        return (InternalCDORevision)revision;
       }
+    });
 
-      return transaction;
-    }
-    catch (RuntimeException ex)
+    transaction.addListener(new LifecycleEventAdapter()
     {
-      closeRemoteSession(remoteSession);
-      throw ex;
-    }
-    catch (Error ex)
-    {
-      closeRemoteSession(remoteSession);
-      throw ex;
-    }
+      @Override
+      protected void onDeactivated(ILifecycle lifecycle)
+      {
+        closeRemoteSession(remoteSession);
+      }
+    });
+
+    return transaction;
+  }
+
+  private InternalCDOTransaction handleMergeConflict(ConflictException ex)
+  {
+    throw ex;
   }
 
   private CDOChangeSetData getMergeResult(CDOMerger merger, CDOBranchPoint basePoint, CDOBranchPoint remotePoint,
@@ -695,9 +763,7 @@ public class CDOWorkspaceImpl extends Notifier implements InternalCDOWorkspace
   public void revert(CDOChangeSetData revertData)
   {
     final CDOBranch localBranch = localSessionHead.getBranch();
-
-    IStoreAccessor.Raw accessor = getLocalWriter(null);
-    StoreThreadLocal.setAccessor(accessor);
+    IStoreAccessor.Raw accessor = beginRawAccess(null);
 
     final List<InternalCDORevision> changedRevisions = new ArrayList<InternalCDORevision>();
     for (CDORevisionKey key : revertData.getChangedObjects())
@@ -864,12 +930,7 @@ public class CDOWorkspaceImpl extends Notifier implements InternalCDOWorkspace
 
         clearBase();
         setTimeStamp(info.getTimeStamp());
-
-        for (CDOIDAndVersion key : changes.getNewObjects())
-        {
-          ids.add(key.getID());
-        }
-
+        addIDs(ids, changes.getNewObjects());
         return info;
       }
       finally
@@ -911,23 +972,13 @@ public class CDOWorkspaceImpl extends Notifier implements InternalCDOWorkspace
 
         for (int v = baseRevision.getVersion(); v < localSessionRevision.getVersion(); v++)
         {
-          if (accessor == null)
-          {
-            accessor = getLocalWriter(null);
-            StoreThreadLocal.setAccessor(accessor);
-          }
-
+          accessor = beginRawAccess(accessor);
           accessor.rawDelete(id, v, localSessionBranch, eClass, new Monitor());
         }
 
         if (localSessionRevision.getVersion() != remoteRevision.getVersion())
         {
-          if (accessor == null)
-          {
-            accessor = getLocalWriter(null);
-            StoreThreadLocal.setAccessor(accessor);
-          }
-
+          accessor = beginRawAccess(accessor);
           accessor.rawDelete(id, localSessionRevision.getVersion(), localSessionBranch, eClass, new Monitor());
 
           // Local session revisions are not cached and can directly be modified and stored in the local repository.
@@ -946,6 +997,17 @@ public class CDOWorkspaceImpl extends Notifier implements InternalCDOWorkspace
     return ids;
   }
 
+  private IStoreAccessor.Raw beginRawAccess(IStoreAccessor.Raw accessor)
+  {
+    if (accessor == null)
+    {
+      accessor = getLocalWriter(null);
+      StoreThreadLocal.setAccessor(accessor);
+    }
+
+    return accessor;
+  }
+
   private void finishRawAccess(IStoreAccessor.Raw accessor)
   {
     if (accessor != null)
@@ -1348,6 +1410,38 @@ public class CDOWorkspaceImpl extends Notifier implements InternalCDOWorkspace
     fixed = Boolean.parseBoolean(props.get(PROP_FIXED));
   }
 
+  private void addIDs(Set<CDOID> result, Set<CDOID> ids)
+  {
+    result.addAll(ids);
+  }
+
+  private void addIDs(Set<CDOID> result, Map<CDOID, ?> map)
+  {
+    addIDs(result, map.keySet());
+  }
+
+  private void addIDs(Set<CDOID> ids, List<? extends CDOIDAndVersion> keys)
+  {
+    for (CDOIDAndVersion key : keys)
+    {
+      ids.add(key.getID());
+    }
+  }
+
+  private void addIDs(Set<CDOID> ids, CDOChangeSetData changeSetData)
+  {
+    addIDs(ids, changeSetData.getNewObjects());
+    addIDs(ids, changeSetData.getChangedObjects());
+    addIDs(ids, changeSetData.getDetachedObjects());
+  }
+
+  private void addIDs(Set<CDOID> result, CDOCommitContext commitContext)
+  {
+    addIDs(result, commitContext.getNewObjects());
+    addIDs(result, commitContext.getDirtyObjects());
+    addIDs(result, commitContext.getDetachedObjects());
+  }
+
   /**
    * @author Eike Stepper
    */
diff --git a/plugins/org.eclipse.emf.cdo.workspace/src/org/eclipse/emf/cdo/internal/workspace/CachingCDOWorkspaceBase.java b/plugins/org.eclipse.emf.cdo.workspace/src/org/eclipse/emf/cdo/internal/workspace/CachingCDOWorkspaceBase.java
new file mode 100644
index 0000000000..aaf9291d3f
--- /dev/null
+++ b/plugins/org.eclipse.emf.cdo.workspace/src/org/eclipse/emf/cdo/internal/workspace/CachingCDOWorkspaceBase.java
@@ -0,0 +1,118 @@
+/*
+ * Copyright (c) 2015 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
+ */
+package org.eclipse.emf.cdo.internal.workspace;
+
+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.StubCDORevision;
+import org.eclipse.emf.cdo.spi.workspace.InternalCDOWorkspace;
+
+import org.eclipse.emf.ecore.EcorePackage;
+
+import java.io.File;
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+/**
+ * @author Eike Stepper
+ */
+public class CachingCDOWorkspaceBase extends FolderCDOWorkspaceBase
+{
+  private static final CDORevision ADDED = new StubCDORevision(EcorePackage.Literals.EOBJECT)
+  {
+    @Override
+    public String toString()
+    {
+      return "ADDED";
+    }
+  };
+
+  private final Map<CDOID, CDORevision> revisions = new LinkedHashMap<CDOID, CDORevision>();
+
+  private final Map<CDOID, Integer> detachedVersions = new LinkedHashMap<CDOID, Integer>();
+
+  public CachingCDOWorkspaceBase(File folder)
+  {
+    super(folder);
+  }
+
+  @Override
+  public void init(InternalCDOWorkspace workspace)
+  {
+    super.init(workspace);
+
+    for (CDOID id : getIDs())
+    {
+      CDORevision revision = getRevision(id);
+      if (revision == null)
+      {
+        revision = ADDED;
+      }
+
+      revisions.put(id, revision);
+    }
+
+    handleAddedAndDetachedObjects(new AddedAndDetachedHandler()
+    {
+      public void handleAddedAndDetachedHandler(CDOID id, int detachedVersion)
+      {
+        detachedVersions.put(id, detachedVersion);
+      }
+    });
+  }
+
+  @Override
+  protected void doRegisterChangedOrDetachedObject(InternalCDORevision revision)
+  {
+    super.doRegisterChangedOrDetachedObject(revision);
+
+    CDOID id = revision.getID();
+    if (revisions.containsKey(id))
+    {
+      return;
+    }
+
+    revisions.put(id, revision);
+  }
+
+  @Override
+  protected void doRegisterAddedAndDetachedObject(InternalCDORevision revision)
+  {
+    super.doRegisterAddedAndDetachedObject(revision);
+
+    CDOID id = revision.getID();
+    int detachedVersion = revision.getVersion();
+    detachedVersions.put(id, detachedVersion);
+  }
+
+  @Override
+  protected void doRegisterAddedObject(CDOID id)
+  {
+    super.doRegisterAddedObject(id);
+    revisions.put(id, ADDED);
+  }
+
+  @Override
+  protected void doDeregisterObject(CDOID id)
+  {
+    super.doDeregisterObject(id);
+    revisions.remove(id);
+  }
+
+  @Override
+  protected void doClear()
+  {
+    super.doClear();
+    revisions.clear();
+    detachedVersions.clear();
+  }
+}
diff --git a/plugins/org.eclipse.emf.cdo.workspace/src/org/eclipse/emf/cdo/internal/workspace/FolderCDOWorkspaceBase.java b/plugins/org.eclipse.emf.cdo.workspace/src/org/eclipse/emf/cdo/internal/workspace/FolderCDOWorkspaceBase.java
index 414de9374c..916f4a1b35 100644
--- a/plugins/org.eclipse.emf.cdo.workspace/src/org/eclipse/emf/cdo/internal/workspace/FolderCDOWorkspaceBase.java
+++ b/plugins/org.eclipse.emf.cdo.workspace/src/org/eclipse/emf/cdo/internal/workspace/FolderCDOWorkspaceBase.java
@@ -84,44 +84,18 @@ public class FolderCDOWorkspaceBase extends AbstractCDOWorkspaceBase
     return file.length() == 0;
   }
 
-  public void deleteAddedAndDetachedObjects(IStoreAccessor.Raw accessor, CDOBranch branch)
+  public void deleteAddedAndDetachedObjects(final IStoreAccessor.Raw accessor, final CDOBranch branch)
   {
-    if (!addedAndDetachedFile.exists())
+    handleAddedAndDetachedObjects(new AddedAndDetachedHandler()
     {
-      return;
-    }
-
-    FileReader fileReader = null;
-
-    try
-    {
-      fileReader = new FileReader(addedAndDetachedFile);
-
-      @SuppressWarnings("resource")
-      BufferedReader lineReader = new BufferedReader(fileReader);
-
-      String line;
-      while ((line = lineReader.readLine()) != null)
+      public void handleAddedAndDetachedHandler(CDOID id, int detachedVersion)
       {
-        String[] tokens = line.split("\t");
-
-        CDOID id = CDOIDUtil.read(tokens[0]);
-        int detachedVersion = Integer.parseInt(tokens[1]);
-
         for (int v = 1; v <= detachedVersion; v++)
         {
           accessor.rawDelete(id, v, branch, null, new Monitor());
         }
       }
-    }
-    catch (IOException ex)
-    {
-      throw new IllegalStateException("Could not read from " + addedAndDetachedFile, ex);
-    }
-    finally
-    {
-      IOUtil.close(fileReader);
-    }
+    });
   }
 
   @Override
@@ -217,6 +191,43 @@ public class FolderCDOWorkspaceBase extends AbstractCDOWorkspaceBase
     checkExists(file, false);
   }
 
+  protected final void handleAddedAndDetachedObjects(AddedAndDetachedHandler handler)
+  {
+    if (!addedAndDetachedFile.exists())
+    {
+      return;
+    }
+
+    FileReader fileReader = null;
+
+    try
+    {
+      fileReader = new FileReader(addedAndDetachedFile);
+
+      @SuppressWarnings("resource")
+      BufferedReader lineReader = new BufferedReader(fileReader);
+
+      String line;
+      while ((line = lineReader.readLine()) != null)
+      {
+        String[] tokens = line.split("\t");
+
+        CDOID id = CDOIDUtil.read(tokens[0]);
+        int detachedVersion = Integer.parseInt(tokens[1]);
+
+        handler.handleAddedAndDetachedHandler(id, detachedVersion);
+      }
+    }
+    catch (IOException ex)
+    {
+      throw new IllegalStateException("Could not read from " + addedAndDetachedFile, ex);
+    }
+    finally
+    {
+      IOUtil.close(fileReader);
+    }
+  }
+
   protected CDOID getCDOID(String filename)
   {
     return CDOIDUtil.read(filename);
@@ -333,6 +344,14 @@ public class FolderCDOWorkspaceBase extends AbstractCDOWorkspaceBase
   /**
    * @author Eike Stepper
    */
+  public interface AddedAndDetachedHandler
+  {
+    public void handleAddedAndDetachedHandler(CDOID id, int detachedVersion);
+  }
+
+  /**
+   * @author Eike Stepper
+   */
   public static final class Factory extends org.eclipse.net4j.util.factory.Factory
   {
     public static final String TYPE = "folder";
diff --git a/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/cdo/transaction/CDOMerger2.java b/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/cdo/transaction/CDOMerger2.java
new file mode 100644
index 0000000000..6a0d3373b5
--- /dev/null
+++ b/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/cdo/transaction/CDOMerger2.java
@@ -0,0 +1,34 @@
+/*
+ * Copyright (c) 2015 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
+ */
+package org.eclipse.emf.cdo.transaction;
+
+import org.eclipse.emf.cdo.common.commit.CDOChangeSet;
+import org.eclipse.emf.cdo.common.commit.CDOChangeSetData;
+import org.eclipse.emf.cdo.common.id.CDOID;
+import org.eclipse.emf.cdo.view.CDOView;
+
+import java.util.Set;
+
+/**
+ * @author Eike Stepper
+ * @since 4.5
+ */
+public interface CDOMerger2 extends CDOMerger
+{
+  /**
+   * @noreference This method is not intended to be referenced by clients.
+   */
+  @Deprecated
+  public CDOChangeSetData merge(CDOChangeSet target, CDOChangeSet source) throws UnsupportedOperationException;
+
+  public void merge(CDOTransaction localTransaction, CDOView remoteView, Set<CDOID> affectedIDs)
+      throws ConflictException;
+}
diff --git a/plugins/org.eclipse.net4j.tests/META-INF/MANIFEST.MF b/plugins/org.eclipse.net4j.tests/META-INF/MANIFEST.MF
index a131dc475b..c84c8696ca 100644
--- a/plugins/org.eclipse.net4j.tests/META-INF/MANIFEST.MF
+++ b/plugins/org.eclipse.net4j.tests/META-INF/MANIFEST.MF
@@ -16,6 +16,7 @@ Require-Bundle: org.eclipse.core.runtime;bundle-version="[3.5.0,4.0.0)";visibili
  org.eclipse.net4j.http.server;bundle-version="[4.0.0,5.0.0)";visibility:=reexport,
  org.eclipse.net4j.defs;bundle-version="[4.0.0,5.0.0)";visibility:=reexport,
  org.eclipse.net4j.util.defs;bundle-version="[4.0.0,5.0.0)";visibility:=reexport,
+ org.apache.log4j;bundle-version="[1.2.0,2.0.0)",
  org.junit;bundle-version="[4.0.0,5.0.0)";visibility:=reexport
 Export-Package: org.eclipse.net4j.tests;version="4.1.400",
  org.eclipse.net4j.tests.apps;version="4.1.400",
diff --git a/plugins/org.eclipse.net4j.tests/src/org/eclipse/net4j/util/tests/AbstractOMTest.java b/plugins/org.eclipse.net4j.tests/src/org/eclipse/net4j/util/tests/AbstractOMTest.java
index 143b436b09..29758f5a5a 100644
--- a/plugins/org.eclipse.net4j.tests/src/org/eclipse/net4j/util/tests/AbstractOMTest.java
+++ b/plugins/org.eclipse.net4j.tests/src/org/eclipse/net4j/util/tests/AbstractOMTest.java
@@ -33,6 +33,12 @@ import org.eclipse.net4j.util.om.log.PrintLogHandler;
 import org.eclipse.net4j.util.om.trace.ContextTracer;
 import org.eclipse.net4j.util.om.trace.PrintTraceHandler;
 
+import org.apache.log4j.Appender;
+import org.apache.log4j.BasicConfigurator;
+import org.apache.log4j.Layout;
+import org.apache.log4j.spi.ErrorHandler;
+import org.apache.log4j.spi.Filter;
+import org.apache.log4j.spi.LoggingEvent;
 import org.junit.Assert;
 
 import java.io.File;
@@ -753,6 +759,65 @@ public abstract class AbstractOMTest extends TestCase
     skipTest(true);
   }
 
+  public static void disableLog4j()
+  {
+    BasicConfigurator.configure(new Appender()
+    {
+      public void setName(String arg0)
+      {
+      }
+
+      public void setLayout(Layout arg0)
+      {
+      }
+
+      public void setErrorHandler(ErrorHandler arg0)
+      {
+      }
+
+      public boolean requiresLayout()
+      {
+        return false;
+      }
+
+      public String getName()
+      {
+        return null;
+      }
+
+      public Layout getLayout()
+      {
+        return null;
+      }
+
+      public Filter getFilter()
+      {
+        return null;
+      }
+
+      public ErrorHandler getErrorHandler()
+      {
+        return null;
+      }
+
+      public void doAppend(LoggingEvent arg0)
+      {
+      }
+
+      public void close()
+      {
+      }
+
+      public void clearFilters()
+      {
+      }
+
+      public void addFilter(Filter arg0)
+      {
+      }
+    });
+  }
+
   /**
    * @author Eike Stepper
    */
diff --git a/plugins/org.eclipse.net4j.util.ui/src/org/eclipse/net4j/util/ui/UIUtil.java b/plugins/org.eclipse.net4j.util.ui/src/org/eclipse/net4j/util/ui/UIUtil.java
index b63c84f4c6..e8b7bc8ed5 100644
--- a/plugins/org.eclipse.net4j.util.ui/src/org/eclipse/net4j/util/ui/UIUtil.java
+++ b/plugins/org.eclipse.net4j.util.ui/src/org/eclipse/net4j/util/ui/UIUtil.java
@@ -239,7 +239,18 @@ public final class UIUtil
    */
   public static IWorkbenchWindow getActiveWorkbenchWindow()
   {
-    IWorkbenchWindow window = getWorkbench().getActiveWorkbenchWindow();
+    IWorkbench workbench = getWorkbench();
+
+    IWorkbenchWindow window = workbench.getActiveWorkbenchWindow();
+    if (window == null)
+    {
+      IWorkbenchWindow[] windows = workbench.getWorkbenchWindows();
+      if (windows.length != 0)
+      {
+        window = windows[0];
+      }
+    }
+
     if (window == null)
     {
       throw new IllegalStateException("No active window available"); //$NON-NLS-1$
@@ -253,7 +264,18 @@ public final class UIUtil
    */
   public static IWorkbenchPage getActiveWorkbenchPage()
   {
-    IWorkbenchPage page = getActiveWorkbenchWindow().getActivePage();
+    IWorkbenchWindow window = getActiveWorkbenchWindow();
+
+    IWorkbenchPage page = window.getActivePage();
+    if (page == null)
+    {
+      IWorkbenchPage[] pages = window.getPages();
+      if (pages.length != 0)
+      {
+        page = pages[0];
+      }
+    }
+
     if (page == null)
     {
       throw new IllegalStateException("No active page available"); //$NON-NLS-1$