org.apache.reef.wake.remote.transport.netty.NettyChannelHandler.java Source code

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Here is the source code for org.apache.reef.wake.remote.transport.netty.NettyChannelHandler.java

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/**
 * 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.reef.wake.remote.transport.netty;

import io.netty.channel.Channel;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.channel.group.ChannelGroup;
import io.netty.util.ReferenceCountUtil;

import java.util.logging.Level;
import java.util.logging.Logger;

class NettyChannelHandler extends ChannelInboundHandlerAdapter {

    private static final Logger LOG = Logger.getLogger(NettyChannelHandler.class.getName());

    private final String tag;
    private final ChannelGroup channelGroup;
    private final NettyEventListener listener;

    /**
     * Constructs a Netty channel handler
     *
     * @param tag          tag string
     * @param channelGroup the channel group
     * @param listener     the Netty event listener
     */
    public NettyChannelHandler(final String tag, final ChannelGroup channelGroup,
            final NettyEventListener listener) {
        this.tag = tag;
        this.channelGroup = channelGroup;
        this.listener = listener;
    }

    /**
     * Handle the incoming message: pass it to the listener.
     *
     * @param ctx the context object for this handler.
     * @param msg the message.
     * @throws Exception
     */
    @Override
    public void channelRead(final ChannelHandlerContext ctx, final Object msg) throws Exception {
        //LOG.log(Level.FINEST, "Read {0} {1}", new Object[]{ctx.channel(), msg});
        try {
            this.listener.channelRead(ctx, msg);
        } finally {
            ReferenceCountUtil.release(msg);
        }
    }

    /**
     * Handles the channel active event
     *
     * @param ctx the context object for this handler
     * @throws Exception
     */
    @Override
    public void channelActive(final ChannelHandlerContext ctx) throws Exception {
        this.channelGroup.add(ctx.channel());
        this.listener.channelActive(ctx);
        super.channelActive(ctx);
    }

    /**
     * Handles the channel inactive event
     *
     * @param ctx the context object for this handler
     * @throws Exception
     */
    @Override
    public void channelInactive(final ChannelHandlerContext ctx) throws Exception {
        this.listener.channelInactive(ctx);
        super.channelInactive(ctx);
    }

    /**
     * Handles the exception event
     *
     * @param ctx   the context object for this handler
     * @param cause the cause
     * @throws Exception
     */
    @Override
    public void exceptionCaught(final ChannelHandlerContext ctx, final Throwable cause) {
        final Channel channel = ctx.channel();

        LOG.log(Level.INFO, "Unexpected exception from downstream. channel: {0} local: {1} remote: {2}",
                new Object[] { channel, channel.localAddress(), channel.remoteAddress() });
        LOG.log(Level.WARNING, "Unexpected exception from downstream.", cause);
        channel.close();
        this.listener.exceptionCaught(ctx, cause);
    }

}