Java tutorial
/* * Copyright 2016-present Open Networking Laboratory * * Licensed 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. */ package org.onosproject.store.cluster.messaging.impl; import com.google.common.base.Charsets; import io.netty.buffer.ByteBuf; import io.netty.channel.ChannelHandler.Sharable; import io.netty.channel.ChannelHandlerContext; import io.netty.handler.codec.MessageToByteEncoder; import org.onlab.packet.IpAddress; import org.onlab.packet.IpAddress.Version; import org.onosproject.store.cluster.messaging.Endpoint; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import java.io.IOException; /** * Encode InternalMessage out into a byte buffer. */ @Sharable public class MessageEncoder extends MessageToByteEncoder<Object> { // Effectively MessageToByteEncoder<InternalMessage>, // had to specify <Object> to avoid Class Loader not being able to find some classes. private final Logger log = LoggerFactory.getLogger(getClass()); private final int preamble; public MessageEncoder(int preamble) { super(); this.preamble = preamble; } @Override protected void encode(ChannelHandlerContext context, Object rawMessage, ByteBuf out) throws Exception { InternalMessage message = (InternalMessage) rawMessage; out.writeInt(this.preamble); // write time out.writeLong(message.time().logicalTime()); out.writeLong(message.time().logicalCounter()); // write message id out.writeLong(message.id()); Endpoint sender = message.sender(); IpAddress senderIp = sender.host(); if (senderIp.version() == Version.INET) { out.writeByte(0); } else { out.writeByte(1); } out.writeBytes(senderIp.toOctets()); // write sender port out.writeInt(sender.port()); byte[] messageTypeBytes = message.type().getBytes(Charsets.UTF_8); // write length of message type out.writeInt(messageTypeBytes.length); // write message type bytes out.writeBytes(messageTypeBytes); // write message status value out.writeInt(message.status().id()); byte[] payload = message.payload(); // write payload length out.writeInt(payload.length); // write payload. out.writeBytes(payload); } @Override public void exceptionCaught(ChannelHandlerContext context, Throwable cause) { if (cause instanceof IOException) { log.debug("IOException inside channel handling pipeline.", cause); } else { log.error("non-IOException inside channel handling pipeline.", cause); } context.close(); } // Effectively same result as one generated by MessageToByteEncoder<InternalMessage> @Override public final boolean acceptOutboundMessage(Object msg) throws Exception { return msg instanceof InternalMessage; } }