serial.java

This is processing for java examples.

/* -*- mode: java; c-basic-offset: 2; indent-tabs-mode: nil -*- */

/*
  PSerial - class for serial port goodness
  Part of the Processing project - http://processing.org

  Copyright (c) 2004-05 Ben Fry & Casey Reas

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  This library is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General
  Public License along with this library; if not, write to the
  Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  Boston, MA  02111-1307  USA
*/

package processing.serial;
import processing.core.*;

import gnu.io.*;

import java.io.*;
import java.util.*;
import java.lang.reflect.*;


public class Serial implements SerialPortEventListener {

  PApplet parent;
  Method serialEventMethod;

  // properties can be passed in for default values
  // otherwise defaults to 9600 N81

  // these could be made static, which might be a solution
  // for the classloading problem.. because if code ran again,
  // the static class would have an object that could be closed

  public SerialPort port;

  public int rate;
  public int parity;
  public int databits;
  public int stopbits;


  // read buffer and streams

  public InputStream input;
  public OutputStream output;

  byte buffer[] = new byte[32768];
  int bufferIndex;
  int bufferLast;

  //boolean bufferUntil = false;
  int bufferSize = 1;  // how big before reset or event firing
  boolean bufferUntil;
  int bufferUntilByte;


  // defaults

  static String dname = "COM1";
  static int drate = 9600;
  static char dparity = 'N';
  static int ddatabits = 8;
  static float dstopbits = 1;


  public void setProperties(Properties props) {
    dname =
      props.getProperty("serial.port", dname);
    drate =
      Integer.parseInt(props.getProperty("serial.rate", "9600"));
    dparity =
      props.getProperty("serial.parity", "N").charAt(0);
    ddatabits =
      Integer.parseInt(props.getProperty("serial.databits", "8"));
    dstopbits =
      new Float(props.getProperty("serial.stopbits", "1")).floatValue();
  }


  public Serial(PApplet parent) {
    this(parent, dname, drate, dparity, ddatabits, dstopbits);
  }

  public Serial(PApplet parent, int irate) {
    this(parent, dname, irate, dparity, ddatabits, dstopbits);
  }

  public Serial(PApplet parent, String iname, int irate) {
    this(parent, iname, irate, dparity, ddatabits, dstopbits);
  }

  public Serial(PApplet parent, String iname) {
    this(parent, iname, drate, dparity, ddatabits, dstopbits);
  }

  public Serial(PApplet parent, String iname, int irate,
                 char iparity, int idatabits, float istopbits) {
    //if (port != null) port.close();
    this.parent = parent;
    //parent.attach(this);

    this.rate = irate;

    parity = SerialPort.PARITY_NONE;
    if (iparity == 'E') parity = SerialPort.PARITY_EVEN;
    if (iparity == 'O') parity = SerialPort.PARITY_ODD;

    this.databits = idatabits;

    stopbits = SerialPort.STOPBITS_1;
    if (istopbits == 1.5f) stopbits = SerialPort.STOPBITS_1_5;
    if (istopbits == 2) stopbits = SerialPort.STOPBITS_2;

    try {
      Enumeration<?> portList = CommPortIdentifier.getPortIdentifiers();
      while (portList.hasMoreElements()) {
        CommPortIdentifier portId =
          (CommPortIdentifier) portList.nextElement();

        if (portId.getPortType() == CommPortIdentifier.PORT_SERIAL) {
          //System.out.println("found " + portId.getName());
          if (portId.getName().equals(iname)) {
            port = (SerialPort)portId.open("serial madness", 2000);
            input = port.getInputStream();
            output = port.getOutputStream();
            port.setSerialPortParams(rate, databits, stopbits, parity);
            port.addEventListener(this);
            port.notifyOnDataAvailable(true);
            //System.out.println("opening, ready to roll");
          }
        }
      }

    } catch (Exception e) {
      errorMessage("<init>", e);
      //exception = e;
      //e.printStackTrace();
      port = null;
      input = null;
      output = null;
    }

    parent.registerDispose(this);

    // reflection to check whether host applet has a call for
    // public void serialEvent(processing.serial.Serial)
    // which would be called each time an event comes in
    try {
      serialEventMethod =
        parent.getClass().getMethod("serialEvent",
                                    new Class[] { Serial.class });
    } catch (Exception e) {
      // no such method, or an error.. which is fine, just ignore
    }
  }


  /**
   * Stop talking to serial and shut things down.
   * <P>
   * Basically just a user-accessible version of dispose().
   * For now, it just calls dispose(), but dispose shouldn't
   * be called from applets, because in some libraries,
   * dispose() blows shit up if it's called by a user who
   * doesn't know what they're doing.
   */
  public void stop() {
    dispose();
  }


  /**
   * Used by PApplet to shut things down.
   */
  public void dispose() {
    try {
      // do io streams need to be closed first?
      if (input != null) input.close();
      if (output != null) output.close();

    } catch (Exception e) {
      e.printStackTrace();
    }
    input = null;
    output = null;

    try {
      if (port != null) port.close();  // close the port

    } catch (Exception e) {
      e.printStackTrace();
    }
    port = null;
  }


  /**
  * Set the DTR line. Addition from Tom Hulbert.
  */
  public void setDTR(boolean state) {
        port.setDTR(state);
  }


  synchronized public void serialEvent(SerialPortEvent serialEvent) {
    if (serialEvent.getEventType() == SerialPortEvent.DATA_AVAILABLE) {
      try {
        while (input.available() > 0) {
          synchronized (buffer) {
            if (bufferLast == buffer.length) {
              byte temp[] = new byte[bufferLast << 1];
              System.arraycopy(buffer, 0, temp, 0, bufferLast);
              buffer = temp;
            }
            buffer[bufferLast++] = (byte) input.read();
            if (serialEventMethod != null) {
              if ((bufferUntil &&
                   (buffer[bufferLast-1] == bufferUntilByte)) ||
                  (!bufferUntil &&
                   ((bufferLast - bufferIndex) >= bufferSize))) {
                try {
                  serialEventMethod.invoke(parent, new Object[] { this });
                } catch (Exception e) {
                  String msg = "error, disabling serialEvent() for " + port;
                  System.err.println(msg);
                  e.printStackTrace();
                  serialEventMethod = null;
                }
              }
            }
          }
        }

      } catch (IOException e) {
        errorMessage("serialEvent", e);
      }
    }
  }


  /**
   * Set number of bytes to buffer before calling serialEvent()
   * in the host applet.
   */
  public void buffer(int count) {
    bufferUntil = false;
    bufferSize = count;
  }


  /**
   * Set a specific byte to buffer until before calling
   * serialEvent() in the host applet.
   */
  public void bufferUntil(int what) {
    bufferUntil = true;
    bufferUntilByte = what;
  }


  /**
   * Returns the number of bytes that have been read from serial
   * and are waiting to be dealt with by the user.
   */
  public int available() {
    return (bufferLast - bufferIndex);
  }


  /**
   * Ignore all the bytes read so far and empty the buffer.
   */
  public void clear() {
    bufferLast = 0;
    bufferIndex = 0;
  }


  /**
   * Returns a number between 0 and 255 for the next byte that's
   * waiting in the buffer.
   * Returns -1 if there was no byte (although the user should
   * first check available() to see if things are ready to avoid this)
   */
  public int read() {
    if (bufferIndex == bufferLast) return -1;

    synchronized (buffer) {
      int outgoing = buffer[bufferIndex++] & 0xff;
      if (bufferIndex == bufferLast) {  // rewind
        bufferIndex = 0;
        bufferLast = 0;
      }
      return outgoing;
    }
  }


  /**
   * Same as read() but returns the very last value received
   * and clears the buffer. Useful when you just want the most
   * recent value sent over the port.
   */
  public int last() {
    if (bufferIndex == bufferLast) return -1;
    synchronized (buffer) {
      int outgoing = buffer[bufferLast-1];
      bufferIndex = 0;
      bufferLast = 0;
      return outgoing;
    }
  }


  /**
   * Returns the next byte in the buffer as a char.
   * Returns -1, or 0xffff, if nothing is there.
   */
  public char readChar() {
    if (bufferIndex == bufferLast) return (char)(-1);
    return (char) read();
  }