Signal protocol

3 files changed, 143 insertions, 9 deletions

diff --git a/plugins/org.eclipse.net4j/src/org/eclipse/net4j/util/concurrent/AsynchronousWorkSerializer.java b/plugins/org.eclipse.net4j/src/org/eclipse/net4j/util/concurrent/AsynchronousWorkSerializer.java
new file mode 100644
index 0000000000..479b58a64a
--- /dev/null
+++ b/plugins/org.eclipse.net4j/src/org/eclipse/net4j/util/concurrent/AsynchronousWorkSerializer.java
@@ -0,0 +1,127 @@
+/***************************************************************************
+ * Copyright (c) 2004, 2005, 2006 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:
+ *    Eike Stepper - initial API and implementation
+ **************************************************************************/
+package org.eclipse.net4j.util.concurrent;
+
+import java.util.Queue;
+import java.util.concurrent.ConcurrentLinkedQueue;
+import java.util.concurrent.ExecutorService;
+
+/**
+ * @author Eike Stepper
+ */
+public class AsynchronousWorkSerializer implements WorkSerializer, Runnable
+{
+  private ExecutorService executorService;
+
+  private Queue<Runnable> workQueue;
+
+  private Occupation occupation = new Occupation();
+
+  public AsynchronousWorkSerializer(ExecutorService executorService, Queue<Runnable> workQueue)
+  {
+    if (executorService == null)
+    {
+      throw new IllegalArgumentException("executorService == null");
+    }
+
+    this.executorService = executorService;
+    this.workQueue = workQueue;
+  }
+
+  public AsynchronousWorkSerializer(ExecutorService executorService)
+  {
+    this(executorService, new ConcurrentLinkedQueue());
+  }
+
+  public ExecutorService getExecutorService()
+  {
+    return executorService;
+  }
+
+  public void addWork(Runnable work)
+  {
+    workQueue.add(work);
+
+    // isOccupied can (and must) be called unsynchronized here
+    if (!occupation.isOccupied())
+    {
+      synchronized (occupation)
+      {
+        occupation.setOccupied(true);
+      }
+
+      System.out.println(toString() + ": Notifying executor service");
+      executorService.execute(this);
+    }
+  }
+
+  /**
+   * Executed in the context of the
+   * {@link #getExecutorService() executor service}.
+   * <p>
+   */
+  public void run()
+  {
+    synchronized (occupation)
+    {
+      Runnable work;
+      while (occupation.isOccupied() && (work = workQueue.poll()) != null)
+      {
+        try
+        {
+          work.run();
+        }
+        catch (RuntimeException ex)
+        {
+          ex.printStackTrace();
+        }
+      }
+
+      occupation.setOccupied(false);
+    }
+  }
+
+  public void dispose()
+  {
+    if (occupation.isOccupied())
+    {
+      occupation.setOccupied(false);
+    }
+
+    workQueue.clear();
+    workQueue = null;
+    executorService = null;
+  }
+
+  @Override
+  public String toString()
+  {
+    return "AsynchronousWorkSerializer[" + executorService + "]";
+  }
+
+  /**
+   * @author Eike Stepper
+   */
+  private static class Occupation
+  {
+    private boolean occupied = false;
+
+    public boolean isOccupied()
+    {
+      return occupied;
+    }
+
+    public void setOccupied(boolean occupied)
+    {
+      this.occupied = occupied;
+    }
+  }
+}
diff --git a/plugins/org.eclipse.net4j/src/org/eclipse/net4j/util/concurrent/Asynchronizer.java b/plugins/org.eclipse.net4j/src/org/eclipse/net4j/util/concurrent/SynchronousWorkSerializer.java
index 60840f0777..d727aaf974 100644
--- a/plugins/org.eclipse.net4j/src/org/eclipse/net4j/util/concurrent/Asynchronizer.java
+++ b/plugins/org.eclipse.net4j/src/org/eclipse/net4j/util/concurrent/SynchronousWorkSerializer.java
@@ -13,13 +13,24 @@ package org.eclipse.net4j.util.concurrent;
 /**
  * @author Eike Stepper
  */
-public class Asynchronizer
+public class SynchronousWorkSerializer implements WorkSerializer
 {
-  public Asynchronizer()
+  public SynchronousWorkSerializer()
   {
   }
 
   public void addWork(Runnable work)
   {
+    work.run();
+  }
+
+  public void dispose()
+  {
+  }
+
+  @Override
+  public String toString()
+  {
+    return "SynchronousWorkSerializer";
   }
 }
diff --git a/plugins/org.eclipse.net4j/src/org/eclipse/net4j/util/concurrent/Worker.java b/plugins/org.eclipse.net4j/src/org/eclipse/net4j/util/concurrent/WorkSerializer.java
index 0a1d268b18..4539855c14 100644
--- a/plugins/org.eclipse.net4j/src/org/eclipse/net4j/util/concurrent/Worker.java
+++ b/plugins/org.eclipse.net4j/src/org/eclipse/net4j/util/concurrent/WorkSerializer.java
@@ -13,13 +13,9 @@ package org.eclipse.net4j.util.concurrent;
 /**
  * @author Eike Stepper
  */
-public class Worker
+public interface WorkSerializer
 {
-  public Worker()
-  {
-  }
+  public void addWork(Runnable work);
 
-  public void addWork(Runnable work)
-  {
-  }
+  public void dispose();
 }