Java tutorial
package com.lance.appengine.spdy; /* * Copyright 2014 The Netty Project * * The Netty Project licenses this file to you under the Apache License, * version 2.0 (the "License"); you may not use this file except in compliance * with the License. You may obtain a copy of the License at: * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the * License for the specific language governing permissions and limitations * under the License. */ import io.netty.channel.ChannelHandlerAdapter; import io.netty.channel.ChannelHandlerContext; import io.netty.channel.ChannelPromise; import io.netty.handler.codec.spdy.SpdyFrame; import io.netty.util.internal.logging.InternalLogLevel; import io.netty.util.internal.logging.InternalLogger; import io.netty.util.internal.logging.InternalLoggerFactory; /** * Logs SPDY frames for debugging purposes. */ @SuppressWarnings("PMD") public class SpdyFrameLogger extends ChannelHandlerAdapter { private enum Direction { INBOUND, OUTBOUND } protected final InternalLogger logger; private final InternalLogLevel level; public SpdyFrameLogger(InternalLogLevel level) { logger = InternalLoggerFactory.getInstance(getClass()); this.level = level; } @Override public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception { if (acceptMessage(msg)) { log((SpdyFrame) msg, Direction.INBOUND); } super.channelRead(ctx, msg); } @Override public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception { if (acceptMessage(msg)) { log((SpdyFrame) msg, Direction.OUTBOUND); } super.write(ctx, msg, promise); } private static boolean acceptMessage(Object msg) throws Exception { return msg instanceof SpdyFrame; } private void log(SpdyFrame msg, Direction d) { if (logger.isEnabled(level)) { StringBuilder b = new StringBuilder("\n----------------").append(d.name()) .append("--------------------\n"); b.append(msg); b.append("\n------------------------------------"); logger.log(level, b.toString()); } } }