io.atomix.cluster.messaging.impl.MessageEncoder.java Source code

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Here is the source code for io.atomix.cluster.messaging.impl.MessageEncoder.java

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/*
 * Copyright 2016-present Open Networking Foundation
 *
 * 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 io.atomix.cluster.messaging.impl;

import io.atomix.utils.net.Address;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.ByteBufUtil;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.MessageToByteEncoder;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;
import java.net.InetAddress;

/**
 * Encode InternalMessage out into a byte buffer.
 */
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 static final int VERSION = 1;
    private final Logger log = LoggerFactory.getLogger(getClass());

    private final Address address;
    private final int preamble;
    private boolean addressWritten;

    public MessageEncoder(Address address, int preamble) {
        super();
        this.address = address;
        this.preamble = preamble;
    }

    @Override
    protected void encode(ChannelHandlerContext context, Object rawMessage, ByteBuf out) throws Exception {
        if (rawMessage instanceof InternalRequest) {
            encodeRequest((InternalRequest) rawMessage, out);
        } else if (rawMessage instanceof InternalReply) {
            encodeReply((InternalReply) rawMessage, out);
        }
    }

    private void encodeMessage(InternalMessage message, ByteBuf out) {
        // If the address hasn't been written to the channel, write it.
        if (!addressWritten) {
            out.writeShort(VERSION);

            final InetAddress senderIp = address.address();
            final byte[] senderIpBytes = senderIp.getAddress();
            out.writeByte(senderIpBytes.length);
            out.writeBytes(senderIpBytes);

            // write sender port
            out.writeInt(address.port());

            addressWritten = true;
        }

        out.writeByte(message.type().id());
        out.writeInt(this.preamble);

        // write message id
        out.writeLong(message.id());

        final byte[] payload = message.payload();

        // write payload length
        out.writeInt(payload.length);

        // write payload.
        out.writeBytes(payload);
    }

    private void encodeRequest(InternalRequest request, ByteBuf out) {
        encodeMessage(request, out);

        final ByteBuf buf = out.alloc().buffer(ByteBufUtil.utf8MaxBytes(request.subject()));
        try {
            final int length = ByteBufUtil.writeUtf8(buf, request.subject());
            // write length of message type
            out.writeShort(length);
            // write message type bytes
            out.writeBytes(buf);
        } finally {
            buf.release();
        }
    }

    private void encodeReply(InternalReply reply, ByteBuf out) {
        encodeMessage(reply, out);

        // write message status value
        out.writeByte(reply.status().id());
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext context, Throwable cause) {
        try {
            if (cause instanceof IOException) {
                log.debug("IOException inside channel handling pipeline.", cause);
            } else {
                log.error("non-IOException inside channel handling pipeline.", cause);
            }
        } finally {
            context.close();
        }
    }

    // Effectively same result as one generated by MessageToByteEncoder<InternalMessage>
    @Override
    public final boolean acceptOutboundMessage(Object msg) throws Exception {
        return msg instanceof InternalMessage;
    }
}