[247427] Explicit locking

https://bugs.eclipse.org/bugs/show_bug.cgi?id=247427

13 files changed, 668 insertions, 2 deletions

diff --git a/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/cdo/CDOLock.java b/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/cdo/CDOLock.java
new file mode 100644
index 0000000000..a02c8c95c4
--- /dev/null
+++ b/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/cdo/CDOLock.java
@@ -0,0 +1,33 @@
+/***************************************************************************
+ * Copyright (c) 2004 - 2008 Eike Stepper, Germany.
+ * 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:
+ *    Simon McDuff - initial API and implementation
+ **************************************************************************/
+package org.eclipse.emf.cdo;
+
+import org.eclipse.net4j.util.concurrent.RWLockManager;
+
+import java.util.concurrent.locks.Lock;
+
+/**
+ * @author Simon McDuff
+ * @since 2.0
+ */
+public interface CDOLock extends Lock
+{
+  public static final int WAIT = RWLockManager.WAIT;
+
+  public static final int NO_WAIT = RWLockManager.NO_WAIT;
+
+  /**
+   * Return true if it is currently lock.
+   */
+  public boolean isLocked();
+
+  public RWLockManager.LockType getType();
+}
diff --git a/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/cdo/CDOObject.java b/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/cdo/CDOObject.java
index 0f199e8b6e..91eabaa7d9 100644
--- a/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/cdo/CDOObject.java
+++ b/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/cdo/CDOObject.java
@@ -39,5 +39,19 @@ public interface CDOObject extends EObject
    */
   public CDOResource cdoDirectResource();
 
+  /**
+   * Returns read lock associate with this object.
+   * 
+   * @since 2.0
+   */
+  public CDOLock cdoReadLock();
+
+  /**
+   * Returns write lock associate with this object.
+   * 
+   * @since 2.0
+   */
+  public CDOLock cdoWriteLock();
+
   public void cdoReload();
 }
diff --git a/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/cdo/CDOTransaction.java b/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/cdo/CDOTransaction.java
index dd17d2c8bc..d47cd76ff4 100644
--- a/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/cdo/CDOTransaction.java
+++ b/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/cdo/CDOTransaction.java
@@ -39,6 +39,28 @@ public interface CDOTransaction extends CDOView, CDOUserTransaction
   public void setCommitTimeout(long timeout);
 
   /**
+   * Specifies whether locks in this view will be removed when {@link CDOTransaction#commit()} or
+   * {@link CDOTransaction#rollback()} is called.
+   * <p>
+   * If false all locks are kept.
+   * <p>
+   * Default value is true.
+   * 
+   * @since 2.0
+   */
+  public boolean setAutoReleaseLocksEnabled(boolean on);
+
+  /**
+   * Returns true if locks in this view will be removes when {@link CDOTransaction#commit()} or
+   * {@link CDOTransaction#rollback()} is called.
+   * <p>
+   * Default value is true.
+   * 
+   * @since 2.0
+   */
+  public boolean isAutoReleaseLocksEnabled();
+
+  /**
    * @since 2.0
    */
   public long getLastCommitTime();
diff --git a/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/cdo/CDOView.java b/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/cdo/CDOView.java
index ae4e013213..5e8514b5dc 100644
--- a/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/cdo/CDOView.java
+++ b/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/cdo/CDOView.java
@@ -20,6 +20,7 @@ import org.eclipse.emf.cdo.eresource.CDOResourceNode;
 import org.eclipse.emf.cdo.util.ReadOnlyException;
 
 import org.eclipse.net4j.util.collection.CloseableIterator;
+import org.eclipse.net4j.util.concurrent.RWLockManager;
 import org.eclipse.net4j.util.event.INotifier;
 
 import org.eclipse.emf.common.util.URI;
@@ -27,6 +28,7 @@ import org.eclipse.emf.ecore.EObject;
 import org.eclipse.emf.ecore.resource.ResourceSet;
 import org.eclipse.emf.ecore.resource.URIHandler;
 
+import java.util.Collection;
 import java.util.List;
 import java.util.concurrent.locks.ReentrantLock;
 
@@ -337,5 +339,25 @@ public interface CDOView extends CDOProtocolView, INotifier
   /**
    * @since 2.0
    */
+  public void lockObjects(Collection<? extends CDOObject> objects, RWLockManager.LockType lockType, long timeout)
+      throws InterruptedException;
+
+  /**
+   * Unlocks the given locked objects of this view.
+   * 
+   * @since 2.0
+   */
+  public void unlockObjects(Collection<? extends CDOObject> objects, RWLockManager.LockType lockType);
+
+  /**
+   * Unlocks all locked objects of this view.
+   * 
+   * @since 2.0
+   */
+  public void unlockObjects();
+
+  /**
+   * @since 2.0
+   */
   public CDOQuery createQuery(String language, String queryString);
 }
diff --git a/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/CDOObjectImpl.java b/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/CDOObjectImpl.java
index bd266242e5..61b7e3a735 100644
--- a/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/CDOObjectImpl.java
+++ b/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/CDOObjectImpl.java
@@ -11,6 +11,7 @@
  **************************************************************************/
 package org.eclipse.emf.internal.cdo;
 
+import org.eclipse.emf.cdo.CDOLock;
 import org.eclipse.emf.cdo.CDOState;
 import org.eclipse.emf.cdo.CDOView;
 import org.eclipse.emf.cdo.common.id.CDOID;
@@ -29,6 +30,9 @@ import org.eclipse.emf.internal.cdo.util.GenUtil;
 import org.eclipse.emf.internal.cdo.util.ModelUtil;
 
 import org.eclipse.net4j.util.ImplementationError;
+import org.eclipse.net4j.util.WrappedException;
+import org.eclipse.net4j.util.concurrent.RWLockManager;
+import org.eclipse.net4j.util.concurrent.TimeoutRuntimeException;
 import org.eclipse.net4j.util.om.trace.ContextTracer;
 
 import org.eclipse.emf.common.notify.Adapter;
@@ -58,9 +62,12 @@ import org.eclipse.emf.ecore.util.FeatureMap;
 import org.eclipse.emf.ecore.util.InternalEList;
 
 import java.util.Collection;
+import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
 import java.util.ListIterator;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.locks.Condition;
 
 /**
  * @author Eike Stepper
@@ -78,7 +85,7 @@ public class CDOObjectImpl extends EStoreEObjectImpl implements InternalCDOObjec
   private InternalCDORevision revision;
 
   /**
-   * CDO used this list instead of eSettings for transient objects. EMF used eSettings as cache. CDO deactivated the
+   * CDO used this list instead of eSettings for transient objects. EMF used eSettings as cache. CDO deactivates the
    * cache but EMF still used eSettings to store list wrappers. CDO needs another place to store the real list with the
    * actual data (transient mode) and accessible through EStore. This allows CDO to always use the same instance of the
    * list wrapper.
@@ -297,6 +304,34 @@ public class CDOObjectImpl extends EStoreEObjectImpl implements InternalCDOObjec
     cdoSettings = null;
   }
 
+  /**
+   * @since 2.0
+   */
+  public CDOLock cdoReadLock()
+  {
+    if (FSMUtil.isTransient(this) || FSMUtil.isNew(this))
+    {
+      return NOOPLockImpl.INSTANCE;
+    }
+
+    // Should we cache the locks ?
+    return new CDOLockImpl(RWLockManager.LockType.READ);
+  }
+
+  /**
+   * @since 2.0
+   */
+  public CDOLock cdoWriteLock()
+  {
+    if (FSMUtil.isTransient(this) || FSMUtil.isNew(this))
+    {
+      return NOOPLockImpl.INSTANCE;
+    }
+
+    // Should we cache the locks ?
+    return new CDOLockImpl(RWLockManager.LockType.WRITE);
+  }
+
   @SuppressWarnings("unchecked")
   private void populateRevisionFeature(CDOViewImpl view, InternalCDORevision revision, EStructuralFeature eFeature,
       Object[] eSettings, int i)
@@ -976,7 +1011,92 @@ public class CDOObjectImpl extends EStoreEObjectImpl implements InternalCDOObjec
   }
 
   /**
-   * @author Eike Stepper
+   * @author Simon McDuff
+   * @since 2.0
+   */
+  private final class CDOLockImpl implements CDOLock
+  {
+    private RWLockManager.LockType type;
+
+    public CDOLockImpl(RWLockManager.LockType type)
+    {
+      this.type = type;
+    }
+
+    public RWLockManager.LockType getType()
+    {
+      return type;
+    }
+
+    public boolean isLocked()
+    {
+      return cdoView().isLocked(CDOObjectImpl.this, type);
+    }
+
+    public void lock()
+    {
+      try
+      {
+        cdoView().lockObjects(Collections.singletonList(CDOObjectImpl.this), type, CDOLock.WAIT);
+      }
+      catch (InterruptedException ex)
+      {
+        throw WrappedException.wrap(ex);
+      }
+    }
+
+    public void lockInterruptibly() throws InterruptedException
+    {
+      lock();
+    }
+
+    public Condition newCondition()
+    {
+      throw new UnsupportedOperationException();
+    }
+
+    public boolean tryLock()
+    {
+      try
+      {
+        cdoView().lockObjects(Collections.singletonList(CDOObjectImpl.this), type, CDOLock.NO_WAIT);
+        return true;
+      }
+      catch (TimeoutRuntimeException ex)
+      {
+        return false;
+      }
+      catch (InterruptedException ex)
+      {
+        return false;
+      }
+    }
+
+    /**
+     * @throws will
+     *           throw an exception if timeout is reached.
+     */
+    public boolean tryLock(long time, TimeUnit unit) throws InterruptedException
+    {
+      try
+      {
+        cdoView().lockObjects(Collections.singletonList(CDOObjectImpl.this), type, unit.toMillis(time));
+        return true;
+      }
+      catch (TimeoutRuntimeException ex)
+      {
+        return false;
+      }
+    }
+
+    public void unlock()
+    {
+      cdoView().unlockObjects(Collections.singletonList(CDOObjectImpl.this), type);
+    }
+  }
+
+  /**
+   * @author Simon McDuff
    * @since 2.0
    */
   public static class CDOStoreSettingsImpl implements InternalEObject.EStore
diff --git a/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/CDOObjectWrapper.java b/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/CDOObjectWrapper.java
index 78441c6506..699451eac6 100644
--- a/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/CDOObjectWrapper.java
+++ b/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/CDOObjectWrapper.java
@@ -11,6 +11,7 @@
 package org.eclipse.emf.internal.cdo;
 
 import org.eclipse.emf.cdo.CDOView;
+import org.eclipse.emf.cdo.CDOLock;
 import org.eclipse.emf.cdo.common.id.CDOID;
 import org.eclipse.emf.cdo.eresource.impl.CDOResourceImpl;
 
@@ -125,6 +126,22 @@ public abstract class CDOObjectWrapper implements InternalCDOObject
   /**
    * @since 2.0
    */
+  public CDOLock cdoReadLock()
+  {
+    throw new UnsupportedOperationException();
+  }
+
+  /**
+   * @since 2.0
+   */
+  public CDOLock cdoWriteLock()
+  {
+    throw new UnsupportedOperationException();
+  }
+
+  /**
+   * @since 2.0
+   */
   public void eFireRead(int featureID)
   {
     // Do nothing
diff --git a/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/CDOTransactionImpl.java b/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/CDOTransactionImpl.java
index fdf07f55f7..456e9f9f56 100644
--- a/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/CDOTransactionImpl.java
+++ b/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/CDOTransactionImpl.java
@@ -95,6 +95,8 @@ public class CDOTransactionImpl extends CDOViewImpl implements InternalCDOTransa
 
   private CDOTransactionStrategy transactionStrategy;
 
+  private boolean autoReleaseLocksEnabled = true;
+
   public CDOTransactionImpl(int id, CDOSessionImpl session)
   {
     super(session, id);
@@ -168,6 +170,29 @@ public class CDOTransactionImpl extends CDOViewImpl implements InternalCDOTransa
   /**
    * @since 2.0
    */
+  synchronized public boolean setAutoReleaseLocksEnabled(boolean on)
+  {
+    try
+    {
+      return autoReleaseLocksEnabled;
+    }
+    finally
+    {
+      autoReleaseLocksEnabled = on;
+    }
+  }
+
+  /**
+   * @since 2.0
+   */
+  public boolean isAutoReleaseLocksEnabled()
+  {
+    return autoReleaseLocksEnabled;
+  }
+
+  /**
+   * @since 2.0
+   */
   public long getLastCommitTime()
   {
     return lastCommitTime;
@@ -718,6 +743,12 @@ public class CDOTransactionImpl extends CDOViewImpl implements InternalCDOTransa
       // Load from first savepoint up to current savepoint
       loadSavepoint(lastSavepoint, idsOfNewObjectWithDeltas);
 
+      if (lastSavepoint == firstSavepoint && isAutoReleaseLocksEnabled())
+      {
+        // Unlock all objects
+        unlockObjects(null, null);
+      }
+
       Map<CDOIDTemp, CDOID> idMappings = Collections.emptyMap();
       fireEvent(new FinishedEvent(CDOTransactionFinishedEvent.Type.ROLLED_BACK, idMappings));
       for (CDOTransactionHandler handler : getHandlers())
@@ -1158,6 +1189,14 @@ public class CDOTransactionImpl extends CDOViewImpl implements InternalCDOTransa
           throw new TransactionException(ex);
         }
       }
+      else
+      {
+        // Removes locks even if no one touch the transaction
+        if (isAutoReleaseLocksEnabled())
+        {
+          unlockObjects(null, null);
+        }
+      }
     }
 
     @SuppressWarnings("unchecked")
diff --git a/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/CDOViewImpl.java b/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/CDOViewImpl.java
index aaf101509d..01048a54eb 100644
--- a/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/CDOViewImpl.java
+++ b/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/CDOViewImpl.java
@@ -51,14 +51,20 @@ import org.eclipse.emf.cdo.util.ReadOnlyException;
 
 import org.eclipse.emf.internal.cdo.bundle.OM;
 import org.eclipse.emf.internal.cdo.protocol.ChangeSubscriptionRequest;
+import org.eclipse.emf.internal.cdo.protocol.LockObjectsRequest;
+import org.eclipse.emf.internal.cdo.protocol.ObjectLockedRequest;
+import org.eclipse.emf.internal.cdo.protocol.UnlockObjectsRequest;
 import org.eclipse.emf.internal.cdo.query.CDOQueryImpl;
 import org.eclipse.emf.internal.cdo.util.FSMUtil;
 import org.eclipse.emf.internal.cdo.util.ModelUtil;
 
+import org.eclipse.net4j.signal.SignalRemoteException;
 import org.eclipse.net4j.util.ImplementationError;
 import org.eclipse.net4j.util.StringUtil;
+import org.eclipse.net4j.util.WrappedException;
 import org.eclipse.net4j.util.ReflectUtil.ExcludeFromDump;
 import org.eclipse.net4j.util.collection.CloseableIterator;
+import org.eclipse.net4j.util.concurrent.RWLockManager;
 import org.eclipse.net4j.util.om.trace.ContextTracer;
 import org.eclipse.net4j.util.ref.ReferenceValueMap;
 import org.eclipse.net4j.util.transaction.TransactionException;
@@ -215,6 +221,89 @@ public class CDOViewImpl extends org.eclipse.net4j.util.event.Notifier implement
     return lock;
   }
 
+  /**
+   * @throws InterruptedException
+   * @since 2.0
+   */
+  public void lockObjects(Collection<? extends CDOObject> objects, RWLockManager.LockType lockType, long timeout)
+      throws InterruptedException
+  {
+    InterruptedException interruptedException = null;
+    RuntimeException runtimeException = null;
+
+    try
+    {
+      LockObjectsRequest request = new LockObjectsRequest(getSession().getProtocol(), this, objects, timeout, lockType);
+      getSession().getFailOverStrategy().send(request);
+    }
+    catch (SignalRemoteException ex)
+    {
+      if (ex.getCause() instanceof RuntimeException)
+      {
+        runtimeException = (RuntimeException)ex.getCause();
+      }
+      else if (ex.getCause() instanceof InterruptedException)
+      {
+        interruptedException = (InterruptedException)ex.getCause();
+      }
+    }
+    catch (Exception ex)
+    {
+      throw WrappedException.wrap(ex);
+    }
+
+    if (interruptedException != null)
+    {
+      throw interruptedException;
+    }
+
+    if (runtimeException != null)
+    {
+      throw runtimeException;
+    }
+  }
+
+  /**
+   * @since 2.0
+   */
+  public void unlockObjects(Collection<? extends CDOObject> objects, RWLockManager.LockType lockType)
+  {
+    try
+    {
+      UnlockObjectsRequest request = new UnlockObjectsRequest(getSession().getProtocol(), this, objects, lockType);
+      getSession().getFailOverStrategy().send(request);
+    }
+    catch (Exception ex)
+    {
+      throw WrappedException.wrap(ex);
+    }
+  }
+
+  /**
+   * @since 2.0
+   */
+  public void unlockObjects()
+  {
+    unlockObjects(null, null);
+  }
+
+  /**
+   * @throws InterruptedException
+   * @since 2.0
+   */
+  public boolean isLocked(CDOObject object, RWLockManager.LockType lockType)
+  {
+    try
+    {
+      ObjectLockedRequest request = new ObjectLockedRequest(getSession().getProtocol(), this, object, lockType);
+      return getSession().getFailOverStrategy().send(request);
+    }
+    catch (Exception ex)
+    {
+      throw WrappedException.wrap(ex);
+    }
+  }
+
   public boolean isDirty()
   {
     return false;
diff --git a/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/NOOPLockImpl.java b/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/NOOPLockImpl.java
new file mode 100644
index 0000000000..4debb2dc0a
--- /dev/null
+++ b/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/NOOPLockImpl.java
@@ -0,0 +1,71 @@
+/***************************************************************************
+ * Copyright (c) 2004 - 2008 Eike Stepper, Germany.
+ * 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:
+ *    Simon McDuff - initial API and implementation
+ **************************************************************************/
+package org.eclipse.emf.internal.cdo;
+
+import org.eclipse.emf.cdo.CDOLock;
+
+import org.eclipse.net4j.util.concurrent.RWLockManager;
+
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.locks.Condition;
+
+/**
+ * @author Simon McDuff
+ * @since 2.0
+ */
+public class NOOPLockImpl implements CDOLock
+{
+  public static final NOOPLockImpl INSTANCE = new NOOPLockImpl();
+
+  private NOOPLockImpl()
+  {
+  }
+
+  public boolean isLocked()
+  {
+    return false;
+  }
+
+  public void lock()
+  {
+    throw new UnsupportedOperationException();
+  }
+
+  public void lockInterruptibly() throws InterruptedException
+  {
+    throw new UnsupportedOperationException();
+  }
+
+  public Condition newCondition()
+  {
+    return null;
+  }
+
+  public boolean tryLock()
+  {
+    return false;
+  }
+
+  public boolean tryLock(long time, TimeUnit unit) throws InterruptedException
+  {
+    return false;
+  }
+
+  public void unlock()
+  {
+    throw new UnsupportedOperationException();
+  }
+
+  public RWLockManager.LockType getType()
+  {
+    return null;
+  }
+}
diff --git a/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/protocol/CommitTransactionRequest.java b/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/protocol/CommitTransactionRequest.java
index 7648b20f9d..45e51ae26e 100644
--- a/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/protocol/CommitTransactionRequest.java
+++ b/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/protocol/CommitTransactionRequest.java
@@ -106,6 +106,7 @@ public class CommitTransactionRequest extends CDOClientRequest<CommitTransaction
     Collection<CDORevisionDelta> revisionDeltas = commitContext.getRevisionDeltas().values();
     Collection<CDOID> detachedObjects = commitContext.getDetachedObjects().keySet();
 
+    out.writeBoolean(commitContext.getTransaction().isAutoReleaseLocksEnabled());
     out.writeInt(newPackages.size());
     out.writeInt(newResources.size() + newObjects.size());
     out.writeInt(revisionDeltas.size());
diff --git a/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/protocol/LockObjectsRequest.java b/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/protocol/LockObjectsRequest.java
new file mode 100644
index 0000000000..a0fde6d651
--- /dev/null
+++ b/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/protocol/LockObjectsRequest.java
@@ -0,0 +1,83 @@
+/***************************************************************************
+ * Copyright (c) 2004 - 2008 Eike Stepper, Germany.
+ * 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:
+ *    Simon McDuff - initial API and implementation
+ **************************************************************************/
+package org.eclipse.emf.internal.cdo.protocol;
+
+import org.eclipse.emf.cdo.CDOObject;
+import org.eclipse.emf.cdo.CDOView;
+import org.eclipse.emf.cdo.common.CDODataInput;
+import org.eclipse.emf.cdo.common.CDODataOutput;
+import org.eclipse.emf.cdo.common.CDOProtocolConstants;
+
+import org.eclipse.emf.internal.cdo.bundle.OM;
+
+import org.eclipse.net4j.util.concurrent.RWLockManager;
+import org.eclipse.net4j.util.om.trace.ContextTracer;
+
+import java.io.IOException;
+import java.util.Collection;
+
+/**
+ * @author Simon McDuff
+ */
+public class LockObjectsRequest extends CDOClientRequest<Object>
+{
+  private static final ContextTracer PROTOCOL_TRACER = new ContextTracer(OM.DEBUG_PROTOCOL, LockObjectsRequest.class);
+
+  private CDOView view;
+
+  private RWLockManager.LockType lockType;
+
+  private Collection<? extends CDOObject> objects;
+
+  private long timeout;
+
+  public LockObjectsRequest(CDOClientProtocol protocol, CDOView view, Collection<? extends CDOObject> objects,
+      long timeout, RWLockManager.LockType lockType)
+  {
+    super(protocol, CDOProtocolConstants.SIGNAL_LOCK_OBJECTS);
+    this.view = view;
+    this.objects = objects;
+    this.timeout = timeout;
+    this.lockType = lockType;
+  }
+
+  @Override
+  protected void requesting(CDODataOutput out) throws IOException
+  {
+    out.writeInt(view.getViewID());
+    out.writeCDOLockType(lockType);
+    out.writeLong(timeout);
+
+    if (PROTOCOL_TRACER.isEnabled())
+    {
+      PROTOCOL_TRACER.format("Locking of type {0} requested for view {1} with timeout {2}",
+          lockType == RWLockManager.LockType.READ ? "read" : "write", view.getViewID(), timeout);
+    }
+
+    out.writeInt(objects.size());
+    for (CDOObject object : objects)
+    {
+      if (PROTOCOL_TRACER.isEnabled())
+      {
+        PROTOCOL_TRACER.format("Locking requested for objects {0}", object.cdoID());
+      }
+
+      out.writeCDOID(object.cdoID());
+    }
+  }
+
+  @Override
+  protected Object confirming(CDODataInput in) throws IOException
+  {
+    in.readBoolean();
+    return null;
+  }
+}
diff --git a/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/protocol/ObjectLockedRequest.java b/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/protocol/ObjectLockedRequest.java
new file mode 100644
index 0000000000..7de2be3cf6
--- /dev/null
+++ b/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/protocol/ObjectLockedRequest.java
@@ -0,0 +1,66 @@
+/***************************************************************************
+ * Copyright (c) 2004 - 2008 Eike Stepper, Germany.
+ * 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:
+ *    Simon McDuff - initial API and implementation
+ **************************************************************************/
+package org.eclipse.emf.internal.cdo.protocol;
+
+import org.eclipse.emf.cdo.CDOObject;
+import org.eclipse.emf.cdo.CDOView;
+import org.eclipse.emf.cdo.common.CDODataInput;
+import org.eclipse.emf.cdo.common.CDODataOutput;
+import org.eclipse.emf.cdo.common.CDOProtocolConstants;
+
+import org.eclipse.emf.internal.cdo.bundle.OM;
+
+import org.eclipse.net4j.util.concurrent.RWLockManager;
+import org.eclipse.net4j.util.om.trace.ContextTracer;
+
+import java.io.IOException;
+
+/**
+ * @author Simon McDuff
+ */
+public class ObjectLockedRequest extends CDOClientRequest<Boolean>
+{
+  private static final ContextTracer PROTOCOL_TRACER = new ContextTracer(OM.DEBUG_PROTOCOL, ObjectLockedRequest.class);
+
+  private CDOView view;
+
+  private CDOObject object;
+
+  private RWLockManager.LockType lockType;
+
+  public ObjectLockedRequest(CDOClientProtocol protocol, CDOView view, CDOObject object, RWLockManager.LockType lockType)
+  {
+    super(protocol, CDOProtocolConstants.SIGNAL_OBJECT_LOCKED);
+    this.view = view;
+    this.object = object;
+    this.lockType = lockType;
+  }
+
+  @Override
+  protected void requesting(CDODataOutput out) throws IOException
+  {
+    if (PROTOCOL_TRACER.isEnabled())
+    {
+      PROTOCOL_TRACER.format("Requesting if object {0} has  of lock for object {1}", object.cdoID(),
+          lockType == RWLockManager.LockType.READ ? "read" : "write");
+    }
+
+    out.writeInt(view.getViewID());
+    out.writeCDOLockType(lockType);
+    out.writeCDOID(object.cdoID());
+  }
+
+  @Override
+  protected Boolean confirming(CDODataInput in) throws IOException
+  {
+    return in.readBoolean();
+  }
+}
diff --git a/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/protocol/UnlockObjectsRequest.java b/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/protocol/UnlockObjectsRequest.java
new file mode 100644
index 0000000000..294f8f229d
--- /dev/null
+++ b/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/protocol/UnlockObjectsRequest.java
@@ -0,0 +1,89 @@
+/***************************************************************************
+ * Copyright (c) 2004 - 2008 Eike Stepper, Germany.
+ * 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:
+ *    Simon McDuff - initial API and implementation
+ **************************************************************************/
+package org.eclipse.emf.internal.cdo.protocol;
+
+import org.eclipse.emf.cdo.CDOObject;
+import org.eclipse.emf.cdo.CDOView;
+import org.eclipse.emf.cdo.common.CDODataInput;
+import org.eclipse.emf.cdo.common.CDODataOutput;
+import org.eclipse.emf.cdo.common.CDOProtocolConstants;
+
+import org.eclipse.emf.internal.cdo.bundle.OM;
+
+import org.eclipse.net4j.util.concurrent.RWLockManager;
+import org.eclipse.net4j.util.om.trace.ContextTracer;
+
+import java.io.IOException;
+import java.util.Collection;
+
+/**
+ * @author Simon McDuff
+ */
+public class UnlockObjectsRequest extends CDOClientRequest<Boolean>
+{
+  private static final ContextTracer PROTOCOL_TRACER = new ContextTracer(OM.DEBUG_PROTOCOL, UnlockObjectsRequest.class);
+
+  private CDOView view;
+
+  private Collection<? extends CDOObject> objects;
+
+  private RWLockManager.LockType lockType;
+
+  public UnlockObjectsRequest(CDOClientProtocol protocol, CDOView view, Collection<? extends CDOObject> objects,
+      RWLockManager.LockType lockType)
+  {
+    super(protocol, CDOProtocolConstants.SIGNAL_UNLOCK_OBJECTS);
+    this.view = view;
+    this.objects = objects;
+    this.lockType = lockType;
+  }
+
+  @Override
+  protected void requesting(CDODataOutput out) throws IOException
+  {
+    out.writeInt(view.getViewID());
+    out.writeCDOLockType(lockType);
+    if (objects == null)
+    {
+      if (PROTOCOL_TRACER.isEnabled())
+      {
+        PROTOCOL_TRACER.format("Unlocking all objects for view {0}", view.getViewID());
+      }
+
+      out.writeInt(CDOProtocolConstants.RELEASE_ALL_LOCKS);
+    }
+    else
+    {
+      if (PROTOCOL_TRACER.isEnabled())
+      {
+        PROTOCOL_TRACER.format("Unlocking of type {0} requested for view {1}",
+            lockType == RWLockManager.LockType.READ ? "read" : "write", view.getViewID());
+      }
+
+      out.writeInt(objects.size());
+      for (CDOObject object : objects)
+      {
+        if (PROTOCOL_TRACER.isEnabled())
+        {
+          PROTOCOL_TRACER.format("Unlocking requested for objects {0}", object.cdoID());
+        }
+
+        out.writeCDOID(object.cdoID());
+      }
+    }
+  }
+
+  @Override
+  protected Boolean confirming(CDODataInput in) throws IOException
+  {
+    return in.readBoolean();
+  }
+}