fixed finger trouble bugs

examples/embedded/src/main/java/org/eclipse/jetty/embedded/AsyncEchoServlet.java

@@ -0,0 +1,107 @@
+//
+//  ========================================================================
+//  Copyright (c) 1995-2015 Mort Bay Consulting Pty. Ltd.
+//  ------------------------------------------------------------------------
+//  All rights reserved. This program and the accompanying materials
+//  are made available under the terms of the Eclipse Public License v1.0
+//  and Apache License v2.0 which accompanies this distribution.
+//
+//      The Eclipse Public License is available at
+//      http://www.eclipse.org/legal/epl-v10.html
+//
+//      The Apache License v2.0 is available at
+//      http://www.opensource.org/licenses/apache2.0.php
+//
+//  You may elect to redistribute this code under either of these licenses.
+//  ========================================================================
+//
+
+package org.eclipse.jetty.embedded;
+
+import java.io.IOException;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+import javax.servlet.AsyncContext;
+import javax.servlet.ReadListener;
+import javax.servlet.ServletException;
+import javax.servlet.ServletInputStream;
+import javax.servlet.ServletOutputStream;
+import javax.servlet.WriteListener;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+
+public class AsyncEchoServlet extends HttpServlet
+{
+    @Override
+    protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
+    {
+        AsyncContext asyncContext = request.startAsync(request, response);
+        asyncContext.setTimeout(0);
+        Echoer echoer = new Echoer(asyncContext);
+        request.getInputStream().setReadListener(echoer);
+        response.getOutputStream().setWriteListener(echoer);
+    }
+
+    private class Echoer implements ReadListener, WriteListener
+    {
+        private final byte[] buffer = new byte[4096];
+        private final AsyncContext asyncContext;
+        private final ServletInputStream input;
+        private final ServletOutputStream output;
+        private final AtomicBoolean complete = new AtomicBoolean(false);
+
+        private Echoer(AsyncContext asyncContext) throws IOException
+        {
+            this.asyncContext = asyncContext;
+            this.input = asyncContext.getRequest().getInputStream();
+            this.output = asyncContext.getResponse().getOutputStream();
+        }
+        
+        @Override
+        public void onDataAvailable() throws IOException
+        {
+            onWritePossible();
+        }
+
+        @Override
+        public void onAllDataRead() throws IOException
+        {
+            onWritePossible();
+        }
+
+        @Override
+        public void onWritePossible() throws IOException
+        {
+            // This method is called:
+            //   1) after first registering a WriteListener (ready for first write)
+            //   2) after first registering a ReadListener iff write is ready
+            //   3) when a previous write completes after an output.isReady() returns false
+            //   4) from an input callback 
+           
+            // We should try to read, only if we are able to write!
+            while (output.isReady() && input.isReady())
+            {
+                int read = input.read(buffer);
+                if (read<0)
+                {
+                    if (complete.compareAndSet(false,true))
+                        asyncContext.complete();
+                    break;
+                }
+                else if (read>0)
+                {
+                    output.write(buffer, 0, read);
+                }
+            }
+        }
+
+        @Override
+        public void onError(Throwable failure)
+        {
+            failure.printStackTrace();
+            asyncContext.complete();
+        }
+    }
+}