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   1 /**
   2  * Copyright (c) 2010-2021 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.rfxcom.internal.connector;
  14
  15 import java.io.IOException;
  16 import java.util.Arrays;
  17
  18 import org.openhab.binding.rfxcom.internal.exceptions.RFXComTimeoutException;
  19 import org.slf4j.Logger;
  20 import org.slf4j.LoggerFactory;
  21
  22 /**
  23  * RFXCOM stream reader to parse RFXCOM output into messages.
  24  *
  25  * @author Pauli Anttila - Initial contribution
  26  * @author James Hewitt-Thomas - New class
  27  * @author Mike Jagdis - Interruptible read loop
  28  * @author Martin van Wingerden - Slight refactoring for read loop for TCP connector
  29  */
  30 public class RFXComStreamReader extends Thread {
  31     private final Logger logger = LoggerFactory.getLogger(RFXComStreamReader.class);
  32     private static final int MAX_READ_TIMEOUTS = 4;
  33     private static final int MAX_RFXCOM_MESSAGE_LEN = 256;
  34
  35     private RFXComBaseConnector connector;
  36
  37     private class ExceptionHandler implements Thread.UncaughtExceptionHandler {
  38         @Override
  39         public void uncaughtException(Thread thread, Throwable throwable) {
  40             logger.debug("Connector died: ", throwable);
  41             connector.sendErrorToListeners("Connector died: " + throwable.getMessage());
  42         }
  43     }
  44
  45     public RFXComStreamReader(RFXComBaseConnector connector, String threadName) {
  46         super(threadName);
  47         this.connector = connector;
  48         setUncaughtExceptionHandler(new ExceptionHandler());
  49     }
  50
  51     @Override
  52     public void run() {
  53         logger.debug("Data listener started");
  54         byte[] buf = new byte[MAX_RFXCOM_MESSAGE_LEN];
  55
  56         // The stream has (or SHOULD have) a read timeout set. Taking a
  57         // read timeout (read returns 0) between packets gives us a chance
  58         // to check if we've been interrupted. Read interrupts during a
  59         // packet are ignored but if too many timeouts occur we take it as
  60         // meaning the RFXCOM has become missing presumed dead.
  61         try {
  62             while (!Thread.interrupted()) {
  63                 // First byte tells us how long the packet is
  64                 int bytesRead = connector.read(buf, 0, 1);
  65                 int packetLength = buf[0];
  66
  67                 if (bytesRead > 0 && packetLength > 0) {
  68                     logger.trace("Message length is {} bytes", packetLength);
  69                     processMessage(buf, packetLength);
  70                     connector.sendMsgToListeners(Arrays.copyOfRange(buf, 0, packetLength + 1));
  71                 } else if (bytesRead == -1) {
  72                     throw new IOException("End of stream");
  73                 }
  74             }
  75         } catch (IOException | RFXComTimeoutException e) {
  76             logger.debug("Received exception, will report it to listeners", e);
  77             connector.sendErrorToListeners(e.getMessage());
  78         }
  79
  80         logger.debug("Data listener stopped");
  81     }
  82
  83     private void processMessage(byte[] buf, int packetLength) throws IOException, RFXComTimeoutException {
  84         // Now read the rest of the packet
  85         int bufferIndex = 1;
  86         int readTimeoutCount = 1;
  87         while (bufferIndex <= packetLength) {
  88             int bytesRemaining = packetLength - bufferIndex + 1;
  89             logger.trace("Waiting remaining {} bytes from the message", bytesRemaining);
  90             int bytesRead = connector.read(buf, bufferIndex, bytesRemaining);
  91             if (bytesRead > 0) {
  92                 logger.trace("Received {} bytes from the message", bytesRead);
  93                 bufferIndex += bytesRead;
  94                 readTimeoutCount = 1;
  95             } else if (readTimeoutCount++ == MAX_READ_TIMEOUTS) {
  96                 throw new RFXComTimeoutException("Timeout during packet read");
  97             }
  98         }
  99     }
 100 }