Netty: IDE warnings cleanup, removed unnecessary inheritance, simplified code. (#2831)

* IDE warnings cleanup, removed unnecessary inheritance, simplified code.

* IDE warnings cleanup, removed unnecessary inheritance, simplified code. fixes

frameworks/Java/netty/src/main/java/hello/HelloServerHandler.java

@@ -14,19 +14,20 @@ import io.netty.buffer.ByteBuf;
 import io.netty.buffer.Unpooled;
 import io.netty.channel.ChannelFutureListener;
 import io.netty.channel.ChannelHandlerContext;
-import io.netty.channel.SimpleChannelInboundHandler;
+import io.netty.channel.ChannelInboundHandlerAdapter;
 import io.netty.handler.codec.http.DefaultFullHttpResponse;
 import io.netty.handler.codec.http.FullHttpResponse;
 import io.netty.handler.codec.http.HttpHeaderNames;
-import io.netty.handler.codec.http.HttpHeaders;
 import io.netty.handler.codec.http.HttpRequest;
-import io.netty.handler.codec.http.HttpResponseStatus;
-import io.netty.handler.codec.http.HttpVersion;
 import io.netty.util.AsciiString;
 import io.netty.util.CharsetUtil;
+import io.netty.util.ReferenceCountUtil;
 import io.netty.util.concurrent.FastThreadLocal;
 
-public class HelloServerHandler extends SimpleChannelInboundHandler<HttpRequest> {
+import static io.netty.handler.codec.http.HttpResponseStatus.*;
+import static io.netty.handler.codec.http.HttpVersion.*;
+
+public class HelloServerHandler extends ChannelInboundHandlerAdapter {
 
 	private static final FastThreadLocal<DateFormat> FORMAT = new FastThreadLocal<DateFormat>() {
 		@Override
@@ -35,17 +36,17 @@ public class HelloServerHandler extends SimpleChannelInboundHandler<HttpRequest>
 		}
 	};
 
-	private static final ObjectMapper newMapper() {
+	private static ObjectMapper newMapper() {
 		ObjectMapper m = new ObjectMapper();
 		m.registerModule(new AfterburnerModule());
 		return m;
 	}
 
-	private static final Message newMsg() {
+	private static Message newMsg() {
 		return new Message("Hello, World!");
 	}
 
-	private static final int jsonLen() {
+	private static int jsonLen() {
 		try {
 			return newMapper().writeValueAsBytes(newMsg()).length;
 		} catch (JsonProcessingException e) {
@@ -83,34 +84,50 @@ public class HelloServerHandler extends SimpleChannelInboundHandler<HttpRequest>
 	}
 
 	@Override
-	public void channelRead0(ChannelHandlerContext ctx, HttpRequest msg) throws Exception {
-		HttpRequest request = (HttpRequest) msg;
+	public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
+		if (msg instanceof HttpRequest) {
+			try {
+				HttpRequest request = (HttpRequest) msg;
+				process(ctx, request);
+			} finally {
+				ReferenceCountUtil.release(msg);
+			}
+		} else {
+			ctx.fireChannelRead(msg);
+		}
+	}
+
+	private void process(ChannelHandlerContext ctx, HttpRequest request) throws Exception {
 		String uri = request.uri();
 		switch (uri) {
-		case "/plaintext":
-			writeResponse(ctx, request, PLAINTEXT_CONTENT_BUFFER.duplicate(), TYPE_PLAIN, PLAINTEXT_CLHEADER_VALUE);
-			return;
-		case "/json":
-			byte[] json = MAPPER.writeValueAsBytes(newMsg());
-			writeResponse(ctx, request, Unpooled.wrappedBuffer(json), TYPE_JSON, JSON_CLHEADER_VALUE);
-			return;
+			case "/plaintext":
+				writePlainResponse(ctx, PLAINTEXT_CONTENT_BUFFER.duplicate());
+				return;
+			case "/json":
+				byte[] json = MAPPER.writeValueAsBytes(newMsg());
+				writeJsonResponse(ctx, Unpooled.wrappedBuffer(json));
+				return;
 		}
-		FullHttpResponse response = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.NOT_FOUND, Unpooled.EMPTY_BUFFER, false);
+		FullHttpResponse response = new DefaultFullHttpResponse(HTTP_1_1, NOT_FOUND, Unpooled.EMPTY_BUFFER, false);
 		ctx.write(response).addListener(ChannelFutureListener.CLOSE);
 	}
 
-	private void writeResponse(ChannelHandlerContext ctx, HttpRequest request, ByteBuf buf, CharSequence contentType, CharSequence contentLength) {
+	private void writePlainResponse(ChannelHandlerContext ctx, ByteBuf buf) {
+		ctx.write(makeResponse(buf, TYPE_PLAIN, PLAINTEXT_CLHEADER_VALUE), ctx.voidPromise());
+	}
 
-		// Build the response object.
-		FullHttpResponse response = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.OK, buf, false);
-		HttpHeaders headers = response.headers();
-		headers.set(CONTENT_TYPE_ENTITY, contentType);
-		headers.set(SERVER_ENTITY, SERVER_NAME);
-		headers.set(DATE_ENTITY, date);
-		headers.set(CONTENT_LENGTH_ENTITY, contentLength);
+	private void writeJsonResponse(ChannelHandlerContext ctx, ByteBuf buf) {
+		ctx.write(makeResponse(buf, TYPE_JSON, JSON_CLHEADER_VALUE), ctx.voidPromise());
+	}
 
-		// Close the non-keep-alive connection after the write operation is done.
-		ctx.write(response, ctx.voidPromise());
+	private FullHttpResponse makeResponse(ByteBuf buf, CharSequence contentType, CharSequence contentLength) {
+		final FullHttpResponse response = new DefaultFullHttpResponse(HTTP_1_1, OK, buf, false);
+		response.headers()
+				.set(CONTENT_TYPE_ENTITY, contentType)
+				.set(SERVER_ENTITY, SERVER_NAME)
+				.set(DATE_ENTITY, date)
+				.set(CONTENT_LENGTH_ENTITY, contentLength);
+		return response;
 	}
 
 	@Override

frameworks/Java/netty/src/main/java/hello/HelloWebServer.java

@@ -3,7 +3,6 @@ package hello;
 import java.net.InetSocketAddress;
 
 import io.netty.bootstrap.ServerBootstrap;
-import io.netty.buffer.PooledByteBufAllocator;
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelOption;
 import io.netty.channel.EventLoopGroup;
@@ -52,7 +51,6 @@ public class HelloWebServer {
 			b.option(ChannelOption.SO_BACKLOG, 8192);
 			b.option(ChannelOption.SO_REUSEADDR, true);
 			b.group(loupGroup).channel(serverChannelClass).childHandler(new HelloServerInitializer(loupGroup.next()));
-			b.childOption(ChannelOption.ALLOCATOR, new PooledByteBufAllocator(true));
 			b.childOption(ChannelOption.SO_REUSEADDR, true);
 
 			Channel ch = b.bind(inet).sync().channel();