Make ExceptionHandler a class

Author: Alvin Wang

src/main/java/co/cask/http/DefaultExceptionHandler.java

@@ -17,10 +17,14 @@
 package co.cask.http;
 
 import org.jboss.netty.handler.codec.http.HttpRequest;
+import org.jboss.netty.handler.codec.http.HttpResponseStatus;
 
 /**
  * Handles exceptions and provides a response via the {@link HttpResponder}.
  */
-public interface ExceptionHandler {
-  public void handle(Throwable t, HttpRequest request, HttpResponder responder);
+public class ExceptionHandler {
+  public void handle(Throwable t, HttpRequest request, HttpResponder responder) {
+    String message = String.format("Exception encountered while processing request : %s", t.getMessage());
+    responder.sendString(HttpResponseStatus.INTERNAL_SERVER_ERROR, message);
+  }
 }

src/main/java/co/cask/http/ExceptionHandler.java

@@ -113,12 +113,12 @@ public NettyHttpService(InetSocketAddress bindAddress, int bossThreadPoolSize, i
     this.rejectedExecutionHandler = rejectedExecutionHandler;
     this.channelGroup = new DefaultChannelGroup();
     this.resourceHandler = new HttpResourceHandler(httpHandlers, handlerHooks, urlRewriter,
-                                                   new DefaultExceptionHandler());
+                                                   new ExceptionHandler());
     this.handlerContext = new BasicHandlerContext(this.resourceHandler);
     this.httpChunkLimit = httpChunkLimit;
     this.pipelineModifier = null;
     this.sslHandlerFactory = null;
-    this.exceptionHandler = new DefaultExceptionHandler();
+    this.exceptionHandler = new ExceptionHandler();
   }
 
   /**
@@ -342,7 +342,7 @@ protected Builder() {
       channelConfigs = Maps.newHashMap();
       channelConfigs.put("backlog", DEFAULT_CONNECTION_BACKLOG);
       sslHandlerFactory = null;
-      exceptionHandler = new DefaultExceptionHandler();
+      exceptionHandler = new ExceptionHandler();
     }
 
     /**

src/main/java/co/cask/http/NettyHttpService.java

@@ -79,7 +79,7 @@ public static void setup() throws Exception {
     NettyHttpService.Builder builder = NettyHttpService.builder();
     builder.addHttpHandlers(handlers);
     builder.setHttpChunkLimit(75 * 1024);
-    builder.setExceptionHandler(new DefaultExceptionHandler() {
+    builder.setExceptionHandler(new ExceptionHandler() {
       @Override
       public void handle(Throwable t, HttpRequest request, HttpResponder responder) {
         if (t instanceof TestHandler.CustomException) {