Java tutorial
/* * Copyright 2017-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.ofagent.impl; import io.netty.channel.Channel; import io.netty.channel.ChannelDuplexHandler; import io.netty.channel.ChannelHandlerContext; import io.netty.util.ReferenceCountUtil; import org.onosproject.ofagent.api.OFSwitch; import org.projectfloodlight.openflow.protocol.OFMessage; import org.slf4j.Logger; import org.slf4j.LoggerFactory; /** * Implementation of OpenFlow channel handler. * It processes OpenFlow message according to the channel state. */ public final class OFChannelHandler extends ChannelDuplexHandler { private final Logger log = LoggerFactory.getLogger(getClass()); private final OFSwitch ofSwitch; private Channel channel; private ChannelState state; private enum ChannelState { INIT { @Override void processOFMessage(final OFChannelHandler handler, final OFMessage msg) { // TODO implement } }, WAIT_HELLO { @Override void processOFMessage(final OFChannelHandler handler, final OFMessage msg) { // TODO implement } }, WAIT_FEATURE_REQUEST { @Override void processOFMessage(final OFChannelHandler handler, final OFMessage msg) { // TODO implement } }, ESTABLISHED { @Override void processOFMessage(final OFChannelHandler handler, final OFMessage msg) { // TODO implement // TODO add this channel to ofSwitch role service } }; abstract void processOFMessage(final OFChannelHandler handler, final OFMessage msg); } /** * Default constructor. * * @param ofSwitch openflow switch that owns this channel */ public OFChannelHandler(OFSwitch ofSwitch) { this.ofSwitch = ofSwitch; } @Override public void channelActive(ChannelHandlerContext ctx) throws Exception { super.channelActive(ctx); this.channel = ctx.channel(); } @Override public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception { try { OFMessage ofMsg = (OFMessage) msg; // TODO process OF message } finally { ReferenceCountUtil.release(msg); } } @Override public void channelReadComplete(ChannelHandlerContext ctx) throws Exception { ctx.flush(); } @Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) { ctx.close(); } private void setState(ChannelState state) { this.state = state; } }