| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF 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. |
| */ |
| |
| package org.apache.livy.rsc.rpc; |
| |
| import java.util.Map; |
| import java.util.concurrent.ConcurrentHashMap; |
| |
| import io.netty.channel.Channel; |
| import io.netty.channel.ChannelHandlerContext; |
| import io.netty.channel.SimpleChannelInboundHandler; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| /** |
| * An implementation of ChannelInboundHandler that dispatches incoming messages to an instance |
| * method based on the method signature. |
| * <p> |
| * A handler's signature must be of the form: |
| * <p> |
| * <blockquote><tt>protected void handle(ChannelHandlerContext, MessageType)</tt></blockquote> |
| * <p> |
| * Where "MessageType" must match exactly the type of the message to handle. Polymorphism is not |
| * supported. Handlers can return a value, which becomes the RPC reply; if a null is returned, then |
| * a reply is still sent, with an empty payload. |
| */ |
| public abstract class RpcDispatcher extends SimpleChannelInboundHandler<Object> { |
| |
| private static final Logger LOG = LoggerFactory.getLogger(RpcDispatcher.class); |
| |
| private final Map<Channel, Rpc> channelRpc = new ConcurrentHashMap<>(); |
| |
| /** |
| * Override this to add a name to the dispatcher, for debugging purposes. |
| * @return The name of this dispatcher. |
| */ |
| protected String name() { |
| return getClass().getSimpleName(); |
| } |
| |
| public void registerRpc(Channel channel, Rpc rpc) { |
| channelRpc.put(channel, rpc); |
| } |
| |
| public void unregisterRpc(Channel channel) { |
| channelRpc.remove(channel); |
| } |
| |
| private Rpc getRpc(ChannelHandlerContext ctx) { |
| Channel channel = ctx.channel(); |
| if (!channelRpc.containsKey(channel)) { |
| throw new IllegalArgumentException("not existed channel:" + channel); |
| } |
| |
| return channelRpc.get(channel); |
| } |
| |
| @Override |
| protected final void channelRead0(ChannelHandlerContext ctx, Object msg) throws Exception { |
| getRpc(ctx).handleMsg(ctx, msg, getClass(), this); |
| } |
| |
| @Override |
| public final void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) { |
| getRpc(ctx).handleChannelException(ctx, cause); |
| } |
| |
| @Override |
| public final void channelInactive(ChannelHandlerContext ctx) throws Exception { |
| getRpc(ctx).handleChannelInactive(); |
| super.channelInactive(ctx); |
| } |
| } |