re-factor handler classes to possibly enable handlers coded in Ruby

javalib/pom.xml

@@ -74,13 +74,11 @@
       <groupId>org.jruby</groupId>
       <artifactId>jruby</artifactId>
       <version>1.4.0</version>
-      <scope>compile</scope>
     </dependency>
     <dependency>
       <groupId>org.jboss.netty</groupId>
       <artifactId>netty</artifactId>
       <version>3.1.5.GA</version>
-      <scope>compile</scope>
     </dependency>
   </dependencies>
 

javalib/src/main/java/com/github/kevwil/aspen/AspenUpstreamHandlerBase.java

@@ -0,0 +1,46 @@
+package com.github.kevwil.aspen;
+
+import org.jboss.netty.channel.*;
+import org.jboss.netty.handler.codec.frame.TooLongFrameException;
+import org.jboss.netty.handler.codec.http.*;
+import org.jboss.netty.buffer.ChannelBuffers;
+
+/**
+ * Netty callback handler base class with common exception handling
+ *
+ * @author kevwil
+ * @since Dec. 21, 2009
+ */
+public class AspenUpstreamHandlerBase
+extends SimpleChannelUpstreamHandler
+{
+    @SuppressWarnings({"ThrowableResultOfMethodCallIgnored"})
+    @Override
+    public void exceptionCaught( final ChannelHandlerContext ctx, final ExceptionEvent e )
+    throws Exception
+    {
+        Channel ch = e.getChannel();
+        Throwable cause = e.getCause();
+        if( cause instanceof TooLongFrameException )
+        {
+            sendError( ctx, HttpResponseStatus.BAD_REQUEST );
+            return;
+        }
+        cause.printStackTrace();
+        if( ch.isConnected() )
+        {
+            sendError( ctx, HttpResponseStatus.INTERNAL_SERVER_ERROR );
+        }
+    }
+
+    private void sendError( ChannelHandlerContext ctx, HttpResponseStatus status )
+    {
+        HttpResponse response = new DefaultHttpResponse( HttpVersion.HTTP_1_1, status );
+        response.setHeader(
+            HttpHeaders.Names.CONTENT_TYPE, "text/plain; charset=UTF-8" );
+        response.setContent( ChannelBuffers.copiedBuffer(
+            "Failure: " + status.toString() + "\r\n", "UTF-8") );
+        // Close the connection as soon as the error message is sent.
+        ctx.getChannel().write( response ).addListener( ChannelFutureListener.CLOSE );
+    }
+}

javalib/src/main/java/com/github/kevwil/aspen/MultipleInstanceHandler.java

@@ -0,0 +1,23 @@
+package com.github.kevwil.aspen;
+
+import org.jboss.netty.channel.ChannelPipelineCoverage;
+
+/**
+ * Non-thread-safe Netty callback handler
+ *
+ * "one" means you must create a new instance of
+ * this handler type for each new channel. It means
+ * the member variables of the handler instance can not be
+ * shared at all, and violating this contract will
+ * lead the handler to a race condition. 
+ *
+ * You need to override the UpstreamHandler method you want to handle.
+ *
+ * @author kevwil
+ * @since Dec. 21, 2009
+ */
+@ChannelPipelineCoverage("one")
+public class MultipleInstanceHandler
+extends AspenUpstreamHandlerBase
+{
+}

javalib/src/main/java/com/github/kevwil/aspen/NettyServerHandler.java

@@ -11,9 +11,8 @@
  * @author kevwil
  * @since Jun 25, 2009
  */
-@ChannelPipelineCoverage("one")
 public class NettyServerHandler
-extends SimpleChannelUpstreamHandler
+extends MultipleInstanceHandler
 {
     private RackProxy _rack;
 
@@ -31,34 +30,4 @@ public void messageReceived( final ChannelHandlerContext ctx, final MessageEvent
         // write the response out
         e.getChannel().write( response ).addListener( ChannelFutureListener.CLOSE );
     }
-
-    @SuppressWarnings({"ThrowableResultOfMethodCallIgnored"})
-    @Override
-    public void exceptionCaught( final ChannelHandlerContext ctx, final ExceptionEvent e )
-    throws Exception
-    {
-        Channel ch = e.getChannel();
-        Throwable cause = e.getCause();
-        if( cause instanceof TooLongFrameException )
-        {
-            sendError( ctx, HttpResponseStatus.BAD_REQUEST );
-            return;
-        }
-        cause.printStackTrace();
-        if( ch.isConnected() )
-        {
-            sendError( ctx, HttpResponseStatus.INTERNAL_SERVER_ERROR );
-        }
-    }
-
-    private void sendError( ChannelHandlerContext ctx, HttpResponseStatus status )
-    {
-        HttpResponse response = new DefaultHttpResponse( HttpVersion.HTTP_1_1, status );
-        response.setHeader(
-            HttpHeaders.Names.CONTENT_TYPE, "text/plain; charset=UTF-8" );
-        response.setContent( ChannelBuffers.copiedBuffer(
-            "Failure: " + status.toString() + "\r\n", "UTF-8") );
-        // Close the connection as soon as the error message is sent.
-        ctx.getChannel().write( response ).addListener( ChannelFutureListener.CLOSE );
-    }
 }

javalib/src/main/java/com/github/kevwil/aspen/RackUtil.java

@@ -16,7 +16,7 @@ public final class RackUtil
 {
     private RackUtil(){}
 
-    public static ChannelHandlerContext buildChannelHandlerContext( final String server, final String port )
+    public static ChannelHandlerContext buildDummyChannelHandlerContext( final String server, final String port )
     {
         int p = 80;
         if( port != null && port.length() > 0 )

javalib/src/main/java/com/github/kevwil/aspen/SingleInstanceHandler.java

@@ -0,0 +1,22 @@
+package com.github.kevwil.aspen;
+
+import org.jboss.netty.channel.ChannelPipelineCoverage;
+import org.jboss.netty.channel.SimpleChannelUpstreamHandler;
+
+/**
+ * thread-safe Netty callback handler
+ *
+ * By using this base class, you assert that member variables
+ * are designed to be OK to share among multiple channels (or
+ * there's nothing to share).
+ *
+ * You need to override the UpstreamHandler method you want to handle.
+ *
+ * @author kevwil
+ * @since Dec. 21, 2009
+ */
+@ChannelPipelineCoverage("all")
+public class SingleInstanceHandler
+extends AspenUpstreamHandlerBase
+{
+}

javalib/src/test/java/com/github/kevwil/aspen/RackUtilTest.java

@@ -32,7 +32,7 @@ public void setUp()
     {
         server = "localhost";
         port = "8080";
-        ctx = RackUtil.buildChannelHandlerContext( server, port );
+        ctx = RackUtil.buildDummyChannelHandlerContext( server, port );
         r = new DefaultHttpRequest( HttpVersion.HTTP_1_1, HttpMethod.GET, "http://"+server+":"+port+"/" );
         env = RubyHash.newHash( ruby );
     }
@@ -50,7 +50,7 @@ public void shouldCreateDummyChannelHandlerContextWithLocalServerAddress() throw
     @Test
     public void shouldUsePort80() throws Exception
     {
-        ctx = RackUtil.buildChannelHandlerContext( server, null );
+        ctx = RackUtil.buildDummyChannelHandlerContext( server, null );
         assertNotNull( ctx );
         assertNotNull( ctx.getChannel() );
         assertNotNull( ctx.getChannel().getLocalAddress() );
@@ -88,7 +88,7 @@ public void shouldParseUriFromHostHeader() throws Exception
     @Test
     public void shouldParseServerPortWhenNoneGiven() throws Exception
     {
-        ctx = RackUtil.buildChannelHandlerContext( server, null );
+        ctx = RackUtil.buildDummyChannelHandlerContext( server, null );
         r = new DefaultHttpRequest( HttpVersion.HTTP_1_1, HttpMethod.GET, "http://"+server+"/" );
         RackUtil.doUriRelated( ctx, r, env );