Exemplo n.º 1
0
  /**
   * creates a new send-frame.
   *
   * @param requestRecord, the data to be sent to the reader.
   * @return the composed frame ready for sending to the reader.
   * @throws IOException if the send frame is longer then 65535 bytes.
   */
  static byte[] composeReaderSendFrame(RequestRecord requestRecord) throws IOException {

    byte[] frame;

    // calculating LENGTH (Advanced Protocol-Length)
    int dataLen;
    if (requestRecord.data != null) dataLen = requestRecord.data.length;
    else dataLen = 0;
    // STX + ALENGTH + COM-ADR + CONTROLBYTE + DATA + CRC16
    int length = 1 + 2 + 1 + 1 + dataLen + 2;
    if (length > 65535) {
      throw new IOException("Protocol send frame too long. (>65535)");
    }
    byte[] len = ByteBlock.numberToByteArray(length);

    // constructing send-frame
    frame = new byte[length];
    frame[0] = STX;
    frame[1] = len[2];
    frame[2] = len[3];
    frame[3] = requestRecord.comAdr;
    frame[4] = requestRecord.controlByte;
    for (int i = 0; i < dataLen; i++) {
      frame[5 + i] = requestRecord.data[i];
    }
    // calculating crc16-checksum
    byte[] temp = new byte[length - 2];
    for (int i = 0; i < length - 2; i++) temp[i] = frame[i];
    byte[] cs = CRC16.crc16(temp);
    frame[length - 2] = cs[0];
    frame[length - 1] = cs[1];

    return frame;
  }
Exemplo n.º 2
0
  /**
   * This method gets the answer from the reader and creates a responseRecord which is returned to
   * the caller
   */
  private synchronized ResponseRecord getResponse() throws IOException {

    byte[] buf = null;

    // receiving data...
    // wait for at least 3 bytes of response
    long t0 = System.currentTimeMillis();
    long time = 0;
    while (in.available() < 3) {
      try {
        Thread.sleep(10);
      } catch (InterruptedException ie) {
      }
      time = System.currentTimeMillis() - t0;
      if (time >= timeout) {
        throw new IOException("Timeout occured, no response for " + timeout + "ms.");
      }
    }

    // read first three byte
    byte[] firstthree = new byte[3];
    int stat = in.read(firstthree, 0, 3);
    if (stat != 3) {
      throw new IOException("No data available.");
    }

    // check STX
    if (firstthree[0] != STX) {
      throw new IOException(
          "Received Data not of type 'Protocol Frame: " + "Advanced Protocol-Length'.");
    }

    // get length of response frame
    int msb = ByteBlock.byteToNumber(firstthree[1]);
    int lsb = ByteBlock.byteToNumber(firstthree[2]);
    int len = (msb << 8) + lsb;

    // wait for len - 3 bytes (rest of response)
    while (in.available() < (len - 3)) {
      try {
        Thread.sleep(10);
      } catch (InterruptedException ie) {
      }
      time = System.currentTimeMillis() - t0;
      if (time >= timeout) {
        throw new IOException(
            "Timeout occured, response not completely " + "arrived for " + timeout + "ms.");
      }
    }

    // read len - 3 bytes
    buf = new byte[len - 3];
    stat = in.read(buf, 0, len - 3);
    if (stat != (len - 3)) {
      throw new IOException("No data available.");
    }

    // if more available, frame is too long
    if (in.available() > 0) {
      throw new IOException("Protocol response frame too long.");
    }

    // verify checksum
    byte[] frame = new byte[len];
    for (int i = 0; i < 3; i++) frame[i] = firstthree[i];
    for (int i = 3; i < len; i++) frame[i] = buf[i - 3];
    byte[] cs = CRC16.crc16(frame);
    if ((cs[0] != 0) || (cs[1] != 0)) {
      throw new IOException("Protocol response frame checksum error.");
    }

    // create responseRecord
    ResponseRecord responseRecord = new ResponseRecord();
    // Reader ISO responses
    responseRecord.status = buf[2];
    byte[] data = new byte[buf.length - 5];
    for (int i = 3, j = 0; i < buf.length - 2; i++) {
      data[j++] = buf[i];
    }
    responseRecord.data = data;

    // for debugging only...
    // System.out.println(" buf: (without length) " +
    // ByteBlock.byteArrayToHexString(buf));
    // System.out.println();

    return responseRecord;
  }