serial.java

This is processing for java examples.

  /**
   * Just like last() and readChar().
   */
  public char lastChar() {
    if (bufferIndex == bufferLast) return (char)(-1);
    return (char) last();
  }


  /**
   * Return a byte array of anything that's in the serial buffer.
   * Not particularly memory/speed efficient, because it creates
   * a byte array on each read, but it's easier to use than
   * readBytes(byte b[]) (see below).
   */
  public byte[] readBytes() {
    if (bufferIndex == bufferLast) return null;

    synchronized (buffer) {
      int length = bufferLast - bufferIndex;
      byte outgoing[] = new byte[length];
      System.arraycopy(buffer, bufferIndex, outgoing, 0, length);

      bufferIndex = 0;  // rewind
      bufferLast = 0;
      return outgoing;
    }
  }


  /**
   * Grab whatever is in the serial buffer, and stuff it into a
   * byte buffer passed in by the user. This is more memory/time
   * efficient than readBytes() returning a byte[] array.
   *
   * Returns an int for how many bytes were read. If more bytes
   * are available than can fit into the byte array, only those
   * that will fit are read.
   */
  public int readBytes(byte outgoing[]) {
    if (bufferIndex == bufferLast) return 0;

    synchronized (buffer) {
      int length = bufferLast - bufferIndex;
      if (length > outgoing.length) length = outgoing.length;
      System.arraycopy(buffer, bufferIndex, outgoing, 0, length);

      bufferIndex += length;
      if (bufferIndex == bufferLast) {
        bufferIndex = 0;  // rewind
        bufferLast = 0;
      }
      return length;
    }
  }


  /**
   * Reads from the serial port into a buffer of bytes up to and
   * including a particular character. If the character isn't in
   * the serial buffer, then 'null' is returned.
   */
  public byte[] readBytesUntil(int interesting) {
    if (bufferIndex == bufferLast) return null;
    byte what = (byte)interesting;

    synchronized (buffer) {
      int found = -1;
      for (int k = bufferIndex; k < bufferLast; k++) {
        if (buffer[k] == what) {
          found = k;
          break;
        }
      }
      if (found == -1) return null;

      int length = found - bufferIndex + 1;
      byte outgoing[] = new byte[length];
      System.arraycopy(buffer, bufferIndex, outgoing, 0, length);

      bufferIndex += length;
      if (bufferIndex == bufferLast) {
        bufferIndex = 0;  // rewind
        bufferLast = 0;
      }
      return outgoing;
    }
  }


  /**
   * Reads from the serial port into a buffer of bytes until a
   * particular character. If the character isn't in the serial
   * buffer, then 'null' is returned.
   *
   * If outgoing[] is not big enough, then -1 is returned,
   *   and an error message is printed on the console.
   * If nothing is in the buffer, zero is returned.
   * If 'interesting' byte is not in the buffer, then 0 is returned.
   */
  public int readBytesUntil(int interesting, byte outgoing[]) {
    if (bufferIndex == bufferLast) return 0;
    byte what = (byte)interesting;

    synchronized (buffer) {
      int found = -1;
      for (int k = bufferIndex; k < bufferLast; k++) {
        if (buffer[k] == what) {
          found = k;
          break;
        }
      }
      if (found == -1) return 0;

      int length = found - bufferIndex + 1;
      if (length > outgoing.length) {
        System.err.println("readBytesUntil() byte buffer is" +
                           " too small for the " + length +
                           " bytes up to and including char " + interesting);
        return -1;
      }
      //byte outgoing[] = new byte[length];
      System.arraycopy(buffer, bufferIndex, outgoing, 0, length);

      bufferIndex += length;
      if (bufferIndex == bufferLast) {
        bufferIndex = 0;  // rewind
        bufferLast = 0;
      }
      return length;
    }
  }


  /**
   * Return whatever has been read from the serial port so far
   * as a String. It assumes that the incoming characters are ASCII.
   *
   * If you want to move Unicode data, you can first convert the
   * String to a byte stream in the representation of your choice
   * (i.e. UTF8 or two-byte Unicode data), and send it as a byte array.
   */
  public String readString() {
    if (bufferIndex == bufferLast) return null;
    return new String(readBytes());
  }


  /**
   * Combination of readBytesUntil and readString. See caveats in
   * each function. Returns null if it still hasn't found what
   * you're looking for.
   *
   * If you want to move Unicode data, you can first convert the
   * String to a byte stream in the representation of your choice
   * (i.e. UTF8 or two-byte Unicode data), and send it as a byte array.
   */
  public String readStringUntil(int interesting) {
    byte b[] = readBytesUntil(interesting);
    if (b == null) return null;
    return new String(b);
  }


  /**
   * This will handle both ints, bytes and chars transparently.
   */
  public void write(int what) {  // will also cover char
    try {
      output.write(what & 0xff);  // for good measure do the &
      output.flush();   // hmm, not sure if a good idea

    } catch (Exception e) { // null pointer or serial port dead
      errorMessage("write", e);
    }
  }


  public void write(byte bytes[]) {
    try {
      output.write(bytes);
      output.flush();   // hmm, not sure if a good idea

    } catch (Exception e) { // null pointer or serial port dead
      //errorMessage("write", e);
      e.printStackTrace();
    }
  }


  /**
   * Write a String to the output. Note that this doesn't account
   * for Unicode (two bytes per char), nor will it send UTF8
   * characters.. It assumes that you mean to send a byte buffer
   * (most often the case for networking and serial i/o) and
   * will only use the bottom 8 bits of each char in the string.
   * (Meaning that internally it uses String.getBytes)
   *
   * If you want to move Unicode data, you can first convert the
   * String to a byte stream in the representation of your choice
   * (i.e. UTF8 or two-byte Unicode data), and send it as a byte array.
   */
  public void write(String what) {
    write(what.getBytes());
  }


  /**
   * If this just hangs and never completes on Windows,
   * it may be because the DLL doesn't have its exec bit set.
   * Why the hell that'd be the case, who knows.
   */
  static public String[] list() {
    Vector<String> list = new Vector<String>();
    try {
      //System.err.println("trying");
      Enumeration<?> portList = CommPortIdentifier.getPortIdentifiers();
      //System.err.println("got port list");
      while (portList.hasMoreElements()) {
        CommPortIdentifier portId =
          (CommPortIdentifier) portList.nextElement();
        //System.out.println(portId);

        if (portId.getPortType() == CommPortIdentifier.PORT_SERIAL) {
          String name = portId.getName();
          list.addElement(name);
        }
      }

    } catch (UnsatisfiedLinkError e) {
      //System.err.println("1");
      errorMessage("ports", e);

    } catch (Exception e) {
      //System.err.println("2");
      errorMessage("ports", e);
    }
    //System.err.println("move out");
    String outgoing[] = new String[list.size()];
    list.copyInto(outgoing);
    return outgoing;
  }


  /**
   * General error reporting, all corraled here just in case
   * I think of something slightly more intelligent to do.
   */
  static public void errorMessage(String where, Throwable e) {
    e.printStackTrace();
    throw new RuntimeException("Error inside Serial." + where + "()");
  }
}


  /*
  class SerialMenuListener implements ItemListener {
    //public SerialMenuListener() { }

    public void itemStateChanged(ItemEvent e) {
      int count = serialMenu.getItemCount();
      for (int i = 0; i < count; i++) {
        ((CheckboxMenuItem)serialMenu.getItem(i)).setState(false);
      }
      CheckboxMenuItem item = (CheckboxMenuItem)e.getSource();
      item.setState(true);
      String name = item.getLabel();
      //System.out.println(item.getLabel());
      PdeBase.properties.put("serial.port", name);
      //System.out.println("set to " + get("serial.port"));
    }
  }
  */


  /*
  protected Vector buildPortList() {
    // get list of names for serial ports
    // have the default port checked (if present)
    Vector list = new Vector();

    //SerialMenuListener listener = new SerialMenuListener();
    boolean problem = false;

    // if this is failing, it may be because
    // lib/javax.comm.properties is missing.
    // java is weird about how it searches for java.comm.properties
    // so it tends to be very fragile. i.e. quotes in the CLASSPATH
    // environment variable will hose things.
    try {
      //System.out.println("building port list");
      Enumeration portList = CommPortIdentifier.getPortIdentifiers();
      while (portList.hasMoreElements()) {
        CommPortIdentifier portId =
          (CommPortIdentifier) portList.nextElement();
        //System.out.println(portId);

        if (portId.getPortType() == CommPortIdentifier.PORT_SERIAL) {
          //if (portId.getName().equals(port)) {
          String name = portId.getName();
          //CheckboxMenuItem mi =
          //new CheckboxMenuItem(name, name.equals(defaultName));

          //mi.addItemListener(listener);
          //serialMenu.add(mi);
          list.addElement(name);
        }
      }
    } catch (UnsatisfiedLinkError e) {
      e.printStackTrace();
      problem = true;

    } catch (Exception e) {
      System.out.println("exception building serial menu");
      e.printStackTrace();
    }

    //if (serialMenu.getItemCount() == 0) {
      //System.out.println("dimming serial menu");
    //serialMenu.setEnabled(false);
    //}

    // only warn them if this is the first time
    if (problem && PdeBase.firstTime) {
      JOptionPane.showMessageDialog(this, //frame,
                                    "Serial port support not installed.\n" +
                                    "Check the readme for instructions\n" +
                                    "if you need to use the serial port.    ",
                                    "Serial Port Warning",
                                    JOptionPane.WARNING_MESSAGE);
    }
    return list;
  }
  */