[578460] Provide a global session registry

https://bugs.eclipse.org/bugs/show_bug.cgi?id=578460

7 files changed, 351 insertions, 76 deletions

diff --git a/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/cdo/session/CDOSessionRegistry.java b/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/cdo/session/CDOSessionRegistry.java
new file mode 100644
index 0000000000..3d15b1e3e9
--- /dev/null
+++ b/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/cdo/session/CDOSessionRegistry.java
@@ -0,0 +1,72 @@
+/*
+ * Copyright (c) 2012, 2019 Eike Stepper (Loehne, 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.session;
+
+import org.eclipse.net4j.util.container.IContainer;
+
+/**
+ * A global registry of all open {@link CDOSession sessions}.
+ *
+ * @author Eike Stepper
+ * @since 4.17
+ * @noextend This interface is not intended to be extended by clients.
+ * @noimplement This interface is not intended to be implemented by clients.
+ */
+public interface CDOSessionRegistry extends IContainer<CDOSessionRegistry.Registration>
+{
+  /**
+   * The singleton instance of the {@link CDOSessionRegistry session registry}.
+   */
+  public static final CDOSessionRegistry INSTANCE = org.eclipse.emf.internal.cdo.session.CDOSessionRegistryImpl.INSTANCE;
+
+  /**
+   * A symbolic constant returned from {@link #getID(CDOSession)} if the session is not registered.
+   */
+  public static final int NOT_REGISTERED = 0;
+
+  /**
+   * Returns the {@link Registration#getID() IDs} of all registered {@link CDOSession sessions}.
+   */
+  public int[] getIDs();
+
+  /**
+   * Returns all registered {@link CDOSession sessions}.
+   */
+  public CDOSession[] getSessions();
+
+  /**
+   * Returns the {@link Registration#getID() ID} of the given {@link CDOSession session} if it is registered, {@value #NOT_REGISTERED} otherwise.
+   */
+  public int getID(CDOSession session);
+
+  /**
+   * Returns the {@link CDOSession session} with the given {@link Registration#getID() ID} if it is registered, <code>null</code> otherwise.
+   */
+  public CDOSession getSession(int id);
+
+  /**
+   * A bidirectional mapping between a registered {@link CDOSession session} and its assigned {@link #getID() ID}.
+   *
+   * @author Eike Stepper
+   */
+  public interface Registration
+  {
+    /**
+     * Returns the ID of this registration.
+     */
+    public int getID();
+
+    /**
+     * Returns the {@link CDOSession} of this registration.
+     */
+    public CDOSession getSession();
+  }
+}
diff --git a/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/cdo/view/CDOViewRegistry.java b/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/cdo/view/CDOViewRegistry.java
index 53a8d9c078..da13f869ea 100644
--- a/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/cdo/view/CDOViewRegistry.java
+++ b/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/cdo/view/CDOViewRegistry.java
@@ -11,7 +11,6 @@
 package org.eclipse.emf.cdo.view;
 
 import org.eclipse.emf.cdo.transaction.CDOTransaction;
-import org.eclipse.emf.cdo.view.CDOViewRegistry.Registration;
 
 import org.eclipse.net4j.util.container.IContainer;
 
@@ -23,10 +22,10 @@ import org.eclipse.net4j.util.container.IContainer;
  * @noextend This interface is not intended to be extended by clients.
  * @noimplement This interface is not intended to be implemented by clients.
  */
-public interface CDOViewRegistry extends IContainer<Registration>
+public interface CDOViewRegistry extends IContainer<CDOViewRegistry.Registration>
 {
   /**
-   * The {@link ClassLoader class loader}-wide singleton instance of the {@link CDOViewRegistry view registry}.
+   * The singleton instance of the {@link CDOViewRegistry view registry}.
    */
   public static final CDOViewRegistry INSTANCE = org.eclipse.emf.internal.cdo.view.CDOViewRegistryImpl.INSTANCE;
 
@@ -56,7 +55,7 @@ public interface CDOViewRegistry extends IContainer<Registration>
   public CDOView getView(int id);
 
   /**
-   * A bidirectional mapping between a registered {@link CDOView view} and its {@link ClassLoader class loader}-wide {@link #getID() ID}.
+   * A bidirectional mapping between a registered {@link CDOView view} and its {@link #getID() ID}.
    *
    * @author Eike Stepper
    */
diff --git a/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/session/CDOSessionImpl.java b/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/session/CDOSessionImpl.java
index 65759c4587..244b390d2d 100644
--- a/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/session/CDOSessionImpl.java
+++ b/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/session/CDOSessionImpl.java
@@ -1587,6 +1587,8 @@ public abstract class CDOSessionImpl extends CDOTransactionContainerImpl impleme
 
     checkState(sessionProtocol, "sessionProtocol"); //$NON-NLS-1$
     checkState(remoteSessionManager, "remoteSessionManager"); //$NON-NLS-1$
+
+    CDOSessionRegistryImpl.INSTANCE.register(this);
   }
 
   protected void doActivateAfterBranchManager() throws Exception
@@ -1597,6 +1599,8 @@ public abstract class CDOSessionImpl extends CDOTransactionContainerImpl impleme
   @Override
   protected void doDeactivate() throws Exception
   {
+    CDOSessionRegistryImpl.INSTANCE.deregister(this);
+
     super.doDeactivate();
 
     unhookSessionProtocol();
diff --git a/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/session/CDOSessionRegistryImpl.java b/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/session/CDOSessionRegistryImpl.java
new file mode 100644
index 0000000000..4e08235518
--- /dev/null
+++ b/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/session/CDOSessionRegistryImpl.java
@@ -0,0 +1,109 @@
+/*
+ * Copyright (c) 2012, 2015, 2016, 2019 Eike Stepper (Loehne, 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.internal.cdo.session;
+
+import org.eclipse.emf.cdo.session.CDOSession;
+import org.eclipse.emf.cdo.session.CDOSessionRegistry;
+
+import org.eclipse.emf.internal.cdo.util.AbstractRegistry;
+
+/**
+ * @author Eike Stepper
+ * @since 4.2
+ */
+public class CDOSessionRegistryImpl extends AbstractRegistry<CDOSession, CDOSessionRegistry.Registration> implements CDOSessionRegistry
+{
+  public static final CDOSessionRegistryImpl INSTANCE = new CDOSessionRegistryImpl();
+
+  public CDOSessionRegistryImpl()
+  {
+  }
+
+  @Override
+  public CDOSession[] getSessions()
+  {
+    return getRegisteredElements();
+  }
+
+  @Override
+  public CDOSession getSession(int id)
+  {
+    return getElement(id);
+  }
+
+  @Override
+  protected CDOSession[] newArray(int size)
+  {
+    return new CDOSession[size];
+  }
+
+  @Override
+  protected Registration[] newRegistrationArray(int size)
+  {
+    return new Registration[size];
+  }
+
+  @Override
+  protected Registration newRegistration(int id, CDOSession session)
+  {
+    return new RegistrationImpl(id, session);
+  }
+
+  @Override
+  protected int getRegisteredID(Registration registration)
+  {
+    return registration.getID();
+  }
+
+  @Override
+  protected CDOSession getRegisteredElement(Registration registration)
+  {
+    return registration.getSession();
+  }
+
+  void register(CDOSession session)
+  {
+    registerElement(session);
+  }
+
+  void deregister(CDOSession session)
+  {
+    deregisterElement(session);
+  }
+
+  /**
+   * @author Eike Stepper
+   */
+  private static final class RegistrationImpl implements Registration
+  {
+    private final int id;
+
+    private final CDOSession session;
+
+    public RegistrationImpl(int id, CDOSession session)
+    {
+      this.id = id;
+      this.session = session;
+    }
+
+    @Override
+    public int getID()
+    {
+      return id;
+    }
+
+    @Override
+    public CDOSession getSession()
+    {
+      return session;
+    }
+  }
+}
diff --git a/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/util/AbstractRegistry.java b/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/util/AbstractRegistry.java
new file mode 100644
index 0000000000..9ba36ef4bd
--- /dev/null
+++ b/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/util/AbstractRegistry.java
@@ -0,0 +1,136 @@
+/*
+ * Copyright (c) 2022 Eike Stepper (Loehne, 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.internal.cdo.util;
+
+import org.eclipse.net4j.util.container.Container;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * @author Eike Stepper
+ */
+public abstract class AbstractRegistry<T, R> extends Container<R>
+{
+  public static final int NOT_REGISTERED = 0;
+
+  private final Map<Integer, R> registrationsByID = new HashMap<>();
+
+  private final Map<T, R> registrationsByElement = new HashMap<>();
+
+  private int lastID;
+
+  public AbstractRegistry()
+  {
+  }
+
+  public T[] getRegisteredElements()
+  {
+    R[] registrations = getElements();
+    T[] registeredElements = newArray(registrations.length);
+  
+    for (int i = 0; i < registeredElements.length; i++)
+    {
+      registeredElements[i] = getRegisteredElement(registrations[i]);
+    }
+  
+    return registeredElements;
+  }
+
+  @Override
+  public synchronized R[] getElements()
+  {
+    int size = registrationsByID.size();
+    R[] array = newRegistrationArray(size);
+    return registrationsByID.values().toArray(array);
+  }
+
+  public synchronized T getElement(int id)
+  {
+    R registration = registrationsByID.get(id);
+    if (registration != null)
+    {
+      return getRegisteredElement(registration);
+    }
+  
+    return null;
+  }
+
+  public synchronized int[] getIDs()
+  {
+    int[] result = new int[registrationsByID.size()];
+
+    int i = 0;
+    for (Integer id : registrationsByID.keySet())
+    {
+      result[i++] = id;
+    }
+
+    return result;
+  }
+
+  public synchronized int getID(T element)
+  {
+    R registration = registrationsByElement.get(element);
+    if (registration != null)
+    {
+      return getRegisteredID(registration);
+    }
+
+    return NOT_REGISTERED;
+  }
+
+  protected final void registerElement(T element)
+  {
+    R registration;
+    synchronized (this)
+    {
+      if (registrationsByElement.containsKey(element))
+      {
+        return;
+      }
+
+      int id = ++lastID;
+      registration = newRegistration(id, element);
+
+      registrationsByID.put(id, registration);
+      registrationsByElement.put(element, registration);
+    }
+
+    fireElementAddedEvent(registration);
+  }
+
+  protected final void deregisterElement(T element)
+  {
+    R registration;
+    synchronized (this)
+    {
+      registration = registrationsByElement.remove(element);
+      if (registration != null)
+      {
+        int id = getRegisteredID(registration);
+        registrationsByID.remove(id);
+      }
+    }
+
+    fireElementRemovedEvent(registration);
+  }
+
+  protected abstract T[] newArray(int size);
+
+  protected abstract R[] newRegistrationArray(int size);
+
+  protected abstract R newRegistration(int id, T element);
+
+  protected abstract int getRegisteredID(R registration);
+
+  protected abstract T getRegisteredElement(R registration);
+}
diff --git a/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/view/CDOViewImpl.java b/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/view/CDOViewImpl.java
index 20021fb00d..336b0349f4 100644
--- a/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/view/CDOViewImpl.java
+++ b/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/view/CDOViewImpl.java
@@ -1526,8 +1526,6 @@ public class CDOViewImpl extends AbstractCDOView
       sessionProtocol.openView(viewID, isReadOnly(), this);
     }
 
-    CDOViewRegistryImpl.INSTANCE.register(this);
-
     Runnable runnable = SessionUtil.getTestDelayInViewActivation();
     if (runnable != null)
     {
@@ -1568,12 +1566,15 @@ public class CDOViewImpl extends AbstractCDOView
         throw ex;
       }
     }
+
+    CDOViewRegistryImpl.INSTANCE.register(this);
   }
 
   @Override
   protected void doBeforeDeactivate() throws Exception
   {
     closing = true;
+    CDOViewRegistryImpl.INSTANCE.deregister(this);
 
     // Detach the view set from the view.
     InternalCDOViewSet viewSet = getViewSet();
@@ -1602,7 +1603,6 @@ public class CDOViewImpl extends AbstractCDOView
     unitManager.deactivate();
     commitInfoDistributor.deactivate();
 
-    CDOViewRegistryImpl.INSTANCE.deregister(this);
     LifecycleUtil.deactivate(invalidator, OMLogger.Level.WARN);
 
     try
diff --git a/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/view/CDOViewRegistryImpl.java b/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/view/CDOViewRegistryImpl.java
index 56ebf7a56d..140eb8337f 100644
--- a/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/view/CDOViewRegistryImpl.java
+++ b/plugins/org.eclipse.emf.cdo/src/org/eclipse/emf/internal/cdo/view/CDOViewRegistryImpl.java
@@ -12,116 +12,71 @@ package org.eclipse.emf.internal.cdo.view;
 
 import org.eclipse.emf.cdo.view.CDOView;
 import org.eclipse.emf.cdo.view.CDOViewRegistry;
-import org.eclipse.emf.cdo.view.CDOViewRegistry.Registration;
 
-import org.eclipse.net4j.util.container.Container;
-
-import java.util.HashMap;
-import java.util.Map;
+import org.eclipse.emf.internal.cdo.util.AbstractRegistry;
 
 /**
  * @author Eike Stepper
  * @since 4.2
- * @see CDOView
  */
-public class CDOViewRegistryImpl extends Container<Registration> implements CDOViewRegistry
+public class CDOViewRegistryImpl extends AbstractRegistry<CDOView, CDOViewRegistry.Registration> implements CDOViewRegistry
 {
   public static final CDOViewRegistryImpl INSTANCE = new CDOViewRegistryImpl();
 
-  private final Map<Integer, Registration> ids = new HashMap<>();
-
-  private final Map<CDOView, Registration> views = new HashMap<>();
-
-  private int lastID;
-
   public CDOViewRegistryImpl()
   {
   }
 
   @Override
-  public synchronized Registration[] getElements()
+  public CDOView[] getViews()
   {
-    return ids.values().toArray(new Registration[ids.size()]);
+    return getRegisteredElements();
   }
 
   @Override
-  public synchronized int[] getIDs()
+  public CDOView getView(int id)
   {
-    int[] result = new int[ids.size()];
-
-    int i = 0;
-    for (Integer id : ids.keySet())
-    {
-      result[i++] = id;
-    }
-
-    return result;
+    return getElement(id);
   }
 
   @Override
-  public synchronized CDOView[] getViews()
+  protected CDOView[] newArray(int size)
   {
-    return views.keySet().toArray(new CDOView[views.size()]);
+    return new CDOView[size];
   }
 
   @Override
-  public synchronized int getID(CDOView view)
+  protected Registration[] newRegistrationArray(int size)
   {
-    Registration registration = views.get(view);
-    if (registration != null)
-    {
-      return registration.getID();
-    }
+    return new Registration[size];
+  }
 
-    return NOT_REGISTERED;
+  @Override
+  protected Registration newRegistration(int id, CDOView view)
+  {
+    return new RegistrationImpl(id, view);
   }
 
   @Override
-  public synchronized CDOView getView(int id)
+  protected int getRegisteredID(Registration registration)
   {
-    Registration registration = ids.get(id);
-    if (registration != null)
-    {
-      return registration.getView();
-    }
+    return registration.getID();
+  }
 
-    return null;
+  @Override
+  protected CDOView getRegisteredElement(Registration registration)
+  {
+    return registration.getView();
   }
 
   void register(CDOView view)
   {
-    Registration registration;
-    synchronized (this)
-    {
-      if (views.containsKey(view))
-      {
-        return;
-      }
-
-      int id = ++lastID;
-      registration = new RegistrationImpl(id, view);
-
-      ids.put(id, registration);
-      views.put(view, registration);
-    }
-
-    fireElementAddedEvent(registration);
+    registerElement(view);
   }
 
   void deregister(CDOView view)
   {
-    Registration registration;
-    synchronized (this)
-    {
-      registration = views.remove(view);
-      if (registration != null)
-      {
-        int id = registration.getID();
-        ids.remove(id);
-      }
-    }
-
-    fireElementRemovedEvent(registration);
+    deregisterElement(view);
   }
 
   /**