1 files changed, 64 insertions, 0 deletions
diff --git a/plugins/org.eclipse.net4j.util/src/org/eclipse/net4j/util/concurrent/OnePendingExecutor.java b/plugins/org.eclipse.net4j.util/src/org/eclipse/net4j/util/concurrent/OnePendingExecutor.java
new file mode 100644
index 0000000000..42ce277c27
--- /dev/null
+++ b/plugins/org.eclipse.net4j.util/src/org/eclipse/net4j/util/concurrent/OnePendingExecutor.java
@@ -0,0 +1,64 @@
+/***************************************************************************
+ * 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:
+ *    Eike Stepper - initial API and implementation
+ **************************************************************************/
+package org.eclipse.net4j.util.concurrent;
+
+import java.util.concurrent.Executor;
+
+public class OnePendingExecutor implements Executor
+{
+  private Runnable command;
+
+  private Thread thread;
+
+  public OnePendingExecutor()
+  {
+  }
+
+  public synchronized void execute(Runnable command)
+  {
+    if (this.command != null)
+    {
+      throw new IllegalStateException("One command already pending");
+    }
+
+    this.command = command;
+    if (thread == null)
+    {
+      thread = new Thread()
+      {
+        @Override
+        public void run()
+        {
+          for (;;)
+          {
+            Runnable command;
+            synchronized (OnePendingExecutor.this)
+            {
+              if (OnePendingExecutor.this.command == null)
+              {
+                thread = null;
+                return;
+              }
+
+              command = OnePendingExecutor.this.command;
+              OnePendingExecutor.this.command = null;
+            }
+
+            command.run();
+          }
+        }
+      };
+
+      thread.setDaemon(true);
+      thread.start();
+    }
+  }
+}