Resolved NETTY-82 (Provide a convenient way to shut down a service)

* Added ChannelFactoryResource
* Added ChannelFactory.getExternalResource()
* Updated all client examples to use getExternalResource().release()

src/main/java/org/jboss/netty/channel/ChannelFactory.java

@@ -58,4 +58,14 @@ public interface ChannelFactory {
      * @throws ChannelException if failed to create and open a new channel
      */
     Channel newChannel(ChannelPipeline pipeline);
+
+    /**
+     * Returns the external resources that this factory depends on to function.
+     * Please note that {@link ChannelFactoryResource#release()} can be called
+     * to release all external resources conveniently when the resources are not
+     * used by this factory or any other part of your application.
+     * An unexpected behavior will be resulted in if the returned resources are
+     * released when there's an open channel which is managed by this factory.
+     */
+    ChannelFactoryResource getExternalResource();
 }

src/main/java/org/jboss/netty/channel/ChannelFactoryExecutorResource.java

@@ -0,0 +1,81 @@
+/*
+ * JBoss, Home of Professional Open Source
+ *
+ * Copyright 2008, Red Hat Middleware LLC, and individual contributors
+ * by the @author tags. See the COPYRIGHT.txt in the distribution for a
+ * full listing of individual contributors.
+ *
+ * This is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This software is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this software; if not, write to the Free
+ * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
+ */
+package org.jboss.netty.channel;
+
+import java.util.concurrent.Executor;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * A {@link ChannelFactoryResource} whose underlying resource is a list of
+ * {@link Executor}s.  {@link #release()} will shut down all specified
+ * {@link ExecutorService}s immediately and wait for their termination.
+ * An {@link Executor} which is not an {@link ExecutorService} will be ignored.
+ *
+ * @author The Netty Project (netty-dev@lists.jboss.org)
+ * @author Trustin Lee (tlee@redhat.com)
+ * @version $Rev$, $Date$
+ */
+public class ChannelFactoryExecutorResource implements
+        ChannelFactoryResource {
+
+    private final Executor[] executors;
+
+    /**
+     * Creates a new instance with the specified executors.
+     *
+     * @param executors a list of {@link Executor}s
+     */
+    public ChannelFactoryExecutorResource(Executor... executors) {
+        if (executors == null) {
+            throw new NullPointerException("executors");
+        }
+        this.executors = new Executor[executors.length];
+        for (int i = 0; i < executors.length; i ++) {
+            if (executors[i] == null) {
+                throw new NullPointerException("executors[" + i + "]");
+            }
+            this.executors[i] = executors[i];
+        }
+    }
+
+    public void release() {
+        for (Executor e: executors) {
+            if (!(e instanceof ExecutorService)) {
+                continue;
+            }
+
+            ExecutorService es = (ExecutorService) e;
+            for (;;) {
+                es.shutdownNow();
+                try {
+                    if (es.awaitTermination(1, TimeUnit.SECONDS)) {
+                        break;
+                    }
+                } catch (InterruptedException ex) {
+                    // Ignore.
+                }
+            }
+        }
+    }
+}

src/main/java/org/jboss/netty/channel/ChannelFactoryResource.java

@@ -0,0 +1,45 @@
+/*
+ * JBoss, Home of Professional Open Source
+ *
+ * Copyright 2008, Red Hat Middleware LLC, and individual contributors
+ * by the @author tags. See the COPYRIGHT.txt in the distribution for a
+ * full listing of individual contributors.
+ *
+ * This is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This software is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this software; if not, write to the Free
+ * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
+ */
+package org.jboss.netty.channel;
+
+import java.util.concurrent.ExecutorService;
+
+
+/**
+ * The abstract representation of external resources that a
+ * {@link ChannelFactory} depends on.  A user can release the external
+ * resources such as {@link ExecutorService}s conveniently.
+ *
+ * @author The Netty Project (netty-dev@lists.jboss.org)
+ * @author Trustin Lee (tlee@redhat.com)
+ *
+ * @version $Rev$, $Date$
+ *
+ * @apiviz.exclude
+ */
+public interface ChannelFactoryResource {
+    /**
+     * Releases this resource.
+     */
+    void release();
+}

src/main/java/org/jboss/netty/channel/socket/nio/NioClientSocketChannelFactory.java

@@ -30,8 +30,10 @@ import java.util.concurrent.RejectedExecutionException;
 import java.util.concurrent.TimeUnit;
 
 import org.jboss.netty.channel.Channel;
+import org.jboss.netty.channel.ChannelFactoryResource;
 import org.jboss.netty.channel.ChannelPipeline;
 import org.jboss.netty.channel.ChannelSink;
+import org.jboss.netty.channel.ChannelFactoryExecutorResource;
 import org.jboss.netty.channel.socket.ClientSocketChannelFactory;
 import org.jboss.netty.channel.socket.SocketChannel;
 
@@ -95,6 +97,7 @@ import org.jboss.netty.channel.socket.SocketChannel;
  */
 public class NioClientSocketChannelFactory implements ClientSocketChannelFactory {
 
+    private final ChannelFactoryResource externalResource;
     private final ChannelSink sink;
 
     /**
@@ -137,10 +140,16 @@ public class NioClientSocketChannelFactory implements ClientSocketChannelFactory
                     "workerCount (" + workerCount + ") " +
                     "must be a positive integer.");
         }
+
+        externalResource = new ChannelFactoryExecutorResource(bossExecutor, workerExecutor);
         sink = new NioClientSocketPipelineSink(bossExecutor, workerExecutor, workerCount);
     }
 
     public SocketChannel newChannel(ChannelPipeline pipeline) {
         return new NioClientSocketChannel(this, pipeline, sink);
     }
+
+    public ChannelFactoryResource getExternalResource() {
+        return externalResource;
+    }
 }

src/main/java/org/jboss/netty/channel/socket/nio/NioServerSocketChannelFactory.java

@@ -30,8 +30,10 @@ import java.util.concurrent.RejectedExecutionException;
 import java.util.concurrent.TimeUnit;
 
 import org.jboss.netty.channel.Channel;
+import org.jboss.netty.channel.ChannelFactoryResource;
 import org.jboss.netty.channel.ChannelPipeline;
 import org.jboss.netty.channel.ChannelSink;
+import org.jboss.netty.channel.ChannelFactoryExecutorResource;
 import org.jboss.netty.channel.socket.ServerSocketChannel;
 import org.jboss.netty.channel.socket.ServerSocketChannelFactory;
 
@@ -99,6 +101,7 @@ import org.jboss.netty.channel.socket.ServerSocketChannelFactory;
 public class NioServerSocketChannelFactory implements ServerSocketChannelFactory {
 
     final Executor bossExecutor;
+    private final ChannelFactoryResource externalResource;
     private final ChannelSink sink;
 
     /**
@@ -142,6 +145,7 @@ public class NioServerSocketChannelFactory implements ServerSocketChannelFactory
                     "must be a positive integer.");
         }
         this.bossExecutor = bossExecutor;
+        externalResource = new ChannelFactoryExecutorResource(bossExecutor, workerExecutor);
         sink = new NioServerSocketPipelineSink(workerExecutor, workerCount);
     }
 
@@ -149,4 +153,7 @@ public class NioServerSocketChannelFactory implements ServerSocketChannelFactory
         return new NioServerSocketChannel(this, pipeline, sink);
     }
 
+    public ChannelFactoryResource getExternalResource() {
+        return externalResource;
+    }
 }

src/main/java/org/jboss/netty/channel/socket/oio/OioClientSocketChannelFactory.java

@@ -28,7 +28,9 @@ import java.util.concurrent.RejectedExecutionException;
 import java.util.concurrent.TimeUnit;
 
 import org.jboss.netty.channel.Channel;
+import org.jboss.netty.channel.ChannelFactoryResource;
 import org.jboss.netty.channel.ChannelPipeline;
+import org.jboss.netty.channel.ChannelFactoryExecutorResource;
 import org.jboss.netty.channel.socket.ClientSocketChannelFactory;
 import org.jboss.netty.channel.socket.SocketChannel;
 
@@ -87,6 +89,7 @@ import org.jboss.netty.channel.socket.SocketChannel;
  */
 public class OioClientSocketChannelFactory implements ClientSocketChannelFactory {
 
+    private final ChannelFactoryResource externalResource;
     final OioClientSocketPipelineSink sink;
 
     /**
@@ -99,10 +102,15 @@ public class OioClientSocketChannelFactory implements ClientSocketChannelFactory
         if (workerExecutor == null) {
             throw new NullPointerException("workerExecutor");
         }
+        externalResource = new ChannelFactoryExecutorResource(workerExecutor);
         sink = new OioClientSocketPipelineSink(workerExecutor);
     }
 
     public SocketChannel newChannel(ChannelPipeline pipeline) {
         return new OioClientSocketChannel(this, pipeline, sink);
     }
+
+    public ChannelFactoryResource getExternalResource() {
+        return externalResource;
+    }
 }

src/main/java/org/jboss/netty/channel/socket/oio/OioServerSocketChannelFactory.java

@@ -28,8 +28,10 @@ import java.util.concurrent.RejectedExecutionException;
 import java.util.concurrent.TimeUnit;
 
 import org.jboss.netty.channel.Channel;
+import org.jboss.netty.channel.ChannelFactoryResource;
 import org.jboss.netty.channel.ChannelPipeline;
 import org.jboss.netty.channel.ChannelSink;
+import org.jboss.netty.channel.ChannelFactoryExecutorResource;
 import org.jboss.netty.channel.socket.ServerSocketChannel;
 import org.jboss.netty.channel.socket.ServerSocketChannelFactory;
 
@@ -100,6 +102,7 @@ import org.jboss.netty.channel.socket.ServerSocketChannelFactory;
 public class OioServerSocketChannelFactory implements ServerSocketChannelFactory {
 
     final Executor bossExecutor;
+    private final ChannelFactoryResource externalResource;
     private final ChannelSink sink;
 
     /**
@@ -119,10 +122,15 @@ public class OioServerSocketChannelFactory implements ServerSocketChannelFactory
             throw new NullPointerException("workerExecutor");
         }
         this.bossExecutor = bossExecutor;
+        externalResource = new ChannelFactoryExecutorResource(bossExecutor, workerExecutor);
         sink = new OioServerSocketPipelineSink(workerExecutor);
     }
 
     public ServerSocketChannel newChannel(ChannelPipeline pipeline) {
         return new OioServerSocketChannel(this, pipeline, sink);
     }
+
+    public ChannelFactoryResource getExternalResource() {
+        return externalResource;
+    }
 }

src/main/java/org/jboss/netty/example/factorial/FactorialClient.java

@@ -26,6 +26,7 @@ import java.net.InetSocketAddress;
 import java.util.concurrent.Executors;
 
 import org.jboss.netty.bootstrap.ClientBootstrap;
+import org.jboss.netty.channel.Channel;
 import org.jboss.netty.channel.ChannelFactory;
 import org.jboss.netty.channel.ChannelFuture;
 import org.jboss.netty.channel.socket.nio.NioClientSocketChannelFactory;
@@ -75,17 +76,17 @@ public class FactorialClient {
             bootstrap.connect(new InetSocketAddress(host, port));
 
         // Wait until the connection is made successfully.
+        Channel channel = connectFuture.awaitUninterruptibly().getChannel();
+
         // Get the handler instance to retrieve the answer.
-        FactorialClientHandler handler = (FactorialClientHandler)
+        FactorialClientHandler handler =
-            connectFuture.await().getChannel().getPipeline().getLast();
+            (FactorialClientHandler) channel.getPipeline().getLast();
 
         // Print out the answer.
         System.out.format(
                 "Factorial of %,d is: %,d", count, handler.getFactorial());
 
-        // We should shut down all thread pools here to exit normally.
+        // Shut down all thread pools to exit.
-        // However, it is just fine to call System.exit(0) because we are
+        factory.getExternalResource().release();
-        // finished with the business.
-        System.exit(0);
     }
 }

src/main/java/org/jboss/netty/example/http/HttpClient.java

@@ -80,7 +80,8 @@ public class HttpClient {
         Channel channel = future.awaitUninterruptibly().getChannel();
         if (!future.isSuccess()) {
             future.getCause().printStackTrace();
-            System.exit(0);
+            factory.getExternalResource().release();
+            return;
         }
 
         // Send the HTTP request.

src/main/java/org/jboss/netty/example/securechat/SecureChatClient.java

@@ -78,7 +78,8 @@ public class SecureChatClient {
         Channel channel = future.awaitUninterruptibly().getChannel();
         if (!future.isSuccess()) {
             future.getCause().printStackTrace();
-            System.exit(0);
+            factory.getExternalResource().release();
+            return;
         }
 
         // Read commands from the stdin.
@@ -101,9 +102,7 @@ public class SecureChatClient {
         // all I/O operations are asynchronous in Netty.
         channel.close().awaitUninterruptibly();
 
-        // We should shut down all thread pools here to exit normally.
+        // Shut down all thread pools to exit.
-        // However, it is just fine to call System.exit(0) because we are
+        factory.getExternalResource().release();
-        // finished with the business.
-        System.exit(0);
     }
 }

src/main/java/org/jboss/netty/example/telnet/TelnetClient.java

@@ -76,7 +76,8 @@ public class TelnetClient {
         Channel channel = future.awaitUninterruptibly().getChannel();
         if (!future.isSuccess()) {
             future.getCause().printStackTrace();
-            System.exit(0);
+            factory.getExternalResource();
+            return;
         }
 
         // Read commands from the stdin.
@@ -101,9 +102,7 @@ public class TelnetClient {
         // all I/O operations are asynchronous in Netty.
         channel.close().awaitUninterruptibly();
 
-        // We should shut down all thread pools here to exit normally.
+        // Shut down all thread pools to exit.
-        // However, it is just fine to call System.exit(0) because we are
+        factory.getExternalResource().release();
-        // finished with the business.
-        System.exit(0);
     }
 }