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   1 /**
   2  * Copyright (c) 2010-2023 Contributors to the openHAB project
   3  *
   4  * See the NOTICE file(s) distributed with this work for additional
   5  * information.
   6  *
   7  * This program and the accompanying materials are made available under the
   8  * terms of the Eclipse Public License 2.0 which is available at
   9  * http://www.eclipse.org/legal/epl-2.0
  10  *
  11  * SPDX-License-Identifier: EPL-2.0
  12  */
  13 package org.openhab.binding.ekey.internal.api;
  14
  15 import java.io.IOException;
  16 import java.net.DatagramPacket;
  17 import java.net.DatagramSocket;
  18 import java.net.InetAddress;
  19 import java.net.UnknownHostException;
  20
  21 import org.eclipse.jdt.annotation.NonNullByDefault;
  22 import org.eclipse.jdt.annotation.Nullable;
  23 import org.openhab.binding.ekey.internal.handler.EkeyHandler;
  24 import org.openhab.core.thing.ThingStatus;
  25 import org.slf4j.Logger;
  26 import org.slf4j.LoggerFactory;
  27
  28 /**
  29  * This Class provides the DatagramSocket that listens for eKey packets on the network
  30  * This will run in a thread and can be interrupted by calling <code>stopListener()<code>
  31  * Before starting the thread initialization is required (mode, ip, port and deliminator)
  32  *
  33  * @author Hans-Jörg Merk - Initial contribution
  34  */
  35 @NonNullByDefault
  36 public class EkeyUdpPacketReceiver {
  37
  38     private final Logger logger = LoggerFactory.getLogger(EkeyUdpPacketReceiver.class);
  39
  40     private final int buffersize = 1024;
  41     private final String ipAddress;
  42     private final int port;
  43     private final String readerThreadName;
  44
  45     private @Nullable DatagramSocket socket;
  46
  47     private @Nullable EkeyPacketListener packetListener;
  48
  49     private boolean connected = false;
  50
  51     public EkeyUdpPacketReceiver(final String ipAddress, final int port, final String readerThreadName) {
  52         this.ipAddress = ipAddress;
  53         this.port = port;
  54         this.readerThreadName = readerThreadName;
  55     }
  56
  57     public void openConnection() throws IOException {
  58         closeConnection();
  59
  60         EkeyPacketListener listener = this.packetListener;
  61
  62         socket = new DatagramSocket(port);
  63
  64         Thread udpListener = new Thread(new UDPListener());
  65         udpListener.setName(readerThreadName);
  66         udpListener.setDaemon(true);
  67         udpListener.start();
  68
  69         setConnected(true);
  70         if (listener != null) {
  71             listener.connectionStatusChanged(ThingStatus.ONLINE, null);
  72         }
  73     }
  74
  75     public void closeConnection() {
  76         setConnected(false);
  77         try {
  78             DatagramSocket localSocket = socket;
  79             if (localSocket != null) {
  80                 localSocket.close();
  81                 localSocket = null;
  82             }
  83         } catch (Exception exception) {
  84             logger.debug("closeConnection(): Error closing connection - {}", exception.getMessage());
  85         }
  86     }
  87
  88     private class UDPListener implements Runnable {
  89
  90         /**
  91          * Run method. Runs the MessageListener thread
  92          */
  93         @Override
  94         public void run() {
  95             logger.debug("Starting ekey Packet Receiver");
  96
  97             DatagramSocket localSocket = socket;
  98
  99             if (localSocket == null) {
 100                 throw new IllegalStateException("Cannot access socket.");
 101             }
 102
 103             byte[] lastPacket = null;
 104             DatagramPacket packet = new DatagramPacket(new byte[buffersize], buffersize);
 105             packet.setData(new byte[buffersize]);
 106
 107             while (isConnected()) {
 108                 try {
 109                     logger.trace("Listen for incoming packet");
 110                     localSocket.receive(packet);
 111                     logger.trace("Packet received - {}", packet.getData());
 112                 } catch (IOException exception) {
 113                     logger.debug("Exception during packet read - {}", exception.getMessage());
 114                 }
 115                 InetAddress sourceIp;
 116                 try {
 117                     sourceIp = InetAddress.getByName(ipAddress);
 118                     if (packet.getAddress().equals(sourceIp)) {
 119                         lastPacket = packet.getData();
 120                         readMessage(lastPacket);
 121                     } else {
 122                         logger.warn("Packet received from unknown source- {}", packet.getData());
 123                     }
 124                 } catch (UnknownHostException e) {
 125                     logger.debug("Exception during address conversion - {}", e.getMessage());
 126                 }
 127             }
 128         }
 129     }
 130
 131     public void readMessage(byte[] message) {
 132         EkeyPacketListener listener = this.packetListener;
 133
 134         if (listener != null && message.length != 0) {
 135             listener.messageReceived(message);
 136         }
 137     }
 138
 139     public void addEkeyPacketListener(EkeyPacketListener listener) {
 140         if (this.packetListener == null) {
 141             this.packetListener = listener;
 142         }
 143     }
 144
 145     public void setConnected(boolean connected) {
 146         this.connected = connected;
 147     }
 148
 149     public boolean isConnected() {
 150         return this.connected;
 151     }
 152
 153     public void removeEkeyPacketListener(EkeyHandler ekeyHandler) {
 154         if (this.packetListener != null) {
 155             this.packetListener = null;
 156         }
 157     }
 158 }