[231156] - [concurrency][view model] Improve performance of the executor used in View model.

plugins/org.eclipse.dd.dsf.ui/src/org/eclipse/dd/dsf/ui/concurrent/SimpleDisplayExecutor.java

@@ -0,0 +1,74 @@
+/*******************************************************************************
+ * Copyright (c) 2008 Wind River Systems 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:
+ *     Wind River Systems - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.dd.dsf.ui.concurrent;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.concurrent.Executor;
+import java.util.concurrent.RejectedExecutionException;
+
+import org.eclipse.dd.dsf.concurrent.DsfExecutor;
+import org.eclipse.swt.SWT;
+import org.eclipse.swt.SWTException;
+import org.eclipse.swt.widgets.Display;
+
+/**
+ * A simple executor which uses the display thread to run the submitted 
+ * runnables. It only implements the {@link Executor}, and NOT the more
+ * sophisticated {@link DsfExecutor} (which extends 
+ * {@link java.util.concurrent.ScheduledExecutorService}). However, this 
+ * implementation is much more efficient than DisplayDsfExecutor as it does
+ * not use a separate thread or maintain its own queue.
+ */
+public class SimpleDisplayExecutor implements Executor{
+    /**
+     * Internal mapping of display objects to executors.
+     */
+    private static Map<Display, SimpleDisplayExecutor> fExecutors = Collections.synchronizedMap( new HashMap<Display, SimpleDisplayExecutor>() );
+    
+    /**
+     * Factory method for display executors.
+     * @param display Display to create an executor for.
+     * @return The new (or re-used) executor.
+     */
+    public static SimpleDisplayExecutor getSimpleDisplayExecutor(Display display) {
+        synchronized (fExecutors) {
+            SimpleDisplayExecutor executor = fExecutors.get(display);
+            if (executor == null) {
+                executor = new SimpleDisplayExecutor(display);
+                fExecutors.put(display, executor);
+            }
+            return executor;
+        }
+    }
+    
+    /**
+     * The display class used by this executor to execute the submitted runnables. 
+     */
+    private final Display fDisplay;
+    
+    private SimpleDisplayExecutor(Display display) {
+        fDisplay = display;
+    }
+
+    public void execute(Runnable command) {
+        try {
+            fDisplay.asyncExec(command);
+        } catch (SWTException e) {
+            if (e.code == SWT.ERROR_DEVICE_DISPOSED) {
+                throw new RejectedExecutionException("Display " + fDisplay + " is disposed", e); //$NON-NLS-1$ //$NON-NLS-2$
+            } else {
+                throw e;
+            }
+        }
+    }
+}

plugins/org.eclipse.dd.dsf.ui/src/org/eclipse/dd/dsf/ui/viewmodel/AbstractVMNode.java

@@ -10,10 +10,11 @@
  *******************************************************************************/
 package org.eclipse.dd.dsf.ui.viewmodel;
 
+import java.util.concurrent.Executor;
+
 import org.eclipse.core.runtime.IStatus;
 import org.eclipse.core.runtime.Status;
 import org.eclipse.dd.dsf.concurrent.DataRequestMonitor;
-import org.eclipse.dd.dsf.concurrent.DsfExecutor;
 import org.eclipse.dd.dsf.concurrent.IDsfStatusConstants;
 import org.eclipse.dd.dsf.internal.ui.DsfUIPlugin;
 import org.eclipse.debug.internal.ui.viewers.model.provisional.IChildrenCountUpdate;
@@ -39,7 +40,7 @@ abstract public class AbstractVMNode implements IVMNode {
     /**
      * Accessor method for sub-classes.
      */
-    protected DsfExecutor getExecutor() {
+    protected Executor getExecutor() {
         return fProvider.getExecutor();
     }
 

plugins/org.eclipse.dd.dsf.ui/src/org/eclipse/dd/dsf/ui/viewmodel/AbstractVMProvider.java

@@ -17,13 +17,13 @@ import java.util.LinkedList;
 import java.util.List;
 import java.util.ListIterator;
 import java.util.Map;
+import java.util.concurrent.Executor;
 import java.util.concurrent.RejectedExecutionException;
 
 import org.eclipse.dd.dsf.concurrent.DataRequestMonitor;
-import org.eclipse.dd.dsf.concurrent.DsfExecutor;
 import org.eclipse.dd.dsf.concurrent.IDsfStatusConstants;
 import org.eclipse.dd.dsf.concurrent.RequestMonitor;
-import org.eclipse.dd.dsf.ui.concurrent.DisplayDsfExecutor;
+import org.eclipse.dd.dsf.ui.concurrent.SimpleDisplayExecutor;
 import org.eclipse.dd.dsf.ui.concurrent.ViewerDataRequestMonitor;
 import org.eclipse.debug.internal.ui.viewers.model.provisional.IChildrenCountUpdate;
 import org.eclipse.debug.internal.ui.viewers.model.provisional.IChildrenUpdate;
@@ -75,7 +75,7 @@ abstract public class AbstractVMProvider implements IVMProvider
      * IPresentationContext object (bug 213629).  For now utilize the 
      * assumption that there is only one display. 
      */
-    private final DsfExecutor fExecutor = DisplayDsfExecutor.getDisplayDsfExecutor(Display.getDefault());
+    private final Executor fExecutor = SimpleDisplayExecutor.getSimpleDisplayExecutor(Display.getDefault());
 
     /**
      * The element content provider implementation that this provider delegates to.
@@ -527,12 +527,11 @@ abstract public class AbstractVMProvider implements IVMProvider
      * need to worry about the executor throwing the {@link RejectedExecutionException}
      * exception. 
      */
-    public DsfExecutor getExecutor() { 
+    public Executor getExecutor() { 
         return fExecutor; 
     }
     
     public IModelProxy createModelProxy(Object element, IPresentationContext context) {
-        assert getExecutor().isInExecutorThread();
         
         // Iterate through the current active proxies to try to find a proxy with the same
         // element and re-use it if found.  At the same time purge proxies that are no longer
@@ -568,7 +567,6 @@ abstract public class AbstractVMProvider implements IVMProvider
      * @see IColumnPresentationFactory#createColumnPresentation(IPresentationContext, Object)
      */
     public IColumnPresentation createColumnPresentation(IPresentationContext context, Object element) {
-        assert fExecutor.isInExecutorThread();
         return null;
     }