nifi-nar-bundles/nifi-extension-utils/nifi-event-transport/src/main/java/org/apache/nifi/event/transport/netty/codec/DatagramByteArrayMessageDecoder.java

/*
 * 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.nifi.event.transport.netty.codec;

import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.socket.DatagramPacket;
import io.netty.handler.codec.MessageToMessageDecoder;
import org.apache.nifi.event.transport.message.ByteArrayMessage;

import java.net.InetAddress;
import java.util.List;

/**
 * Message Decoder for bytes received from Datagram Packets
 */
public class DatagramByteArrayMessageDecoder extends MessageToMessageDecoder<DatagramPacket> {
    /**
     * Decode Datagram Packet to Byte Array Message
     *
     * @param channelHandlerContext Channel Handler Context
     * @param datagramPacket Datagram Packet
     * @param decoded Decoded Messages
     */
    @Override
    protected void decode(final ChannelHandlerContext channelHandlerContext, final DatagramPacket datagramPacket, final List<Object> decoded) {
        final ByteBuf content = datagramPacket.content();
        final int readableBytes = content.readableBytes();
        final byte[] bytes = new byte[readableBytes];
        content.readBytes(bytes);

        final InetAddress packetAddress = datagramPacket.sender().getAddress();
        final String address = packetAddress.getHostAddress();
        final ByteArrayMessage message = new ByteArrayMessage(bytes, address);
        decoded.add(message);
    }
}