CommPort.java

/*
 * 	
 *
 * Copyright  1990-2009 Sun Microsystems, Inc. All Rights Reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
 * 
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License version
 * 2 only, as published by the Free Software Foundation.
 * 
 * This program 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
 * General Public License version 2 for more details (a copy is
 * included at /legal/license.txt).
 * 
 * You should have received a copy of the GNU General Public License
 * version 2 along with this work; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 * 
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
 * Clara, CA 95054 or visit www.sun.com if you need additional
 * information or have any questions.
 */

import java.io.*;
import java.util.*;
import javax.comm.*;

public class CommPort {
    CommPortIdentifier portId;
    Enumeration portList;    

    InputStream inputStream;
    OutputStream outputStream;
    SerialPort serialPort;

    static final int MAXSIZE=256;

    public void Init(int portno) throws IOException {
    	//String portname = "COM" + portno;
    	//String portname = "/dev/term/a";
    	String portname = "/dev/ttyS" + portno;

    	System.out.println("Open " + portname);
    	
        portList = CommPortIdentifier.getPortIdentifiers();
        
        while (portList.hasMoreElements()) {
            portId = (CommPortIdentifier) portList.nextElement();
            if (portId.getPortType() == CommPortIdentifier.PORT_SERIAL) {
                 if (portId.getName().equals(portname)) {                
                    return;
                }
            }
        }
        
        throw(new IOException("Can't find port"));
    }
    
    public CommPort(int portno, int baudrate, int data_bits, int stop_bits,
                    int parity) throws IOException {
    	Init(portno);
    	
        try {
            serialPort = (SerialPort) portId.open("SimpleReadApp", 2000);
        } catch (PortInUseException e) {
        	System.out.println("Port is in use!");
        	throw (new IOException("Port in use"));
        }
                
        inputStream = serialPort.getInputStream();
        outputStream = serialPort.getOutputStream();
       
        try {
            serialPort.setSerialPortParams(baudrate,
                data_bits,
                stop_bits,
                parity);
            serialPort.setInputBufferSize(1024);
        } catch (UnsupportedCommOperationException e) {}
    }

    public void close() {
        serialPort.close();
        System.out.println("comm port closed");
    }
	
    public void serialSend(int nBuf) throws IOException {
        byte[] buffer = new byte[4];

        for(int i = 0; i < 4; i++) {
            buffer[3 - i] = (byte)((nBuf >> 8*i) & 0xFF);
            //buffer[i] = (byte)(nBuf >> 8 * i & 0xFF);
        }

        serialSend(buffer, 4);
    }

    // Second parameter viz. length is required because serialSend 
    // may not write all the parameters in the buffer to the serial port. 
    // This is especially true for reading from a socket when the number
    // of bytes read are aften less that the actual number of bytes read.
    public void serialSend(byte[] buf, int length) throws IOException {
        for (int i = 0; i < length; i++) {
            byte ch = buf[i];
            try {
                outputStream.write((int)(ch & 0xff));
            } catch (IOException e) {
                System.out.println("Error while sending");
            }
        }
    }

    public byte[] serialReceiveInt() throws IOException {
        return serialReceive(4);
    }

    public byte[] serialReceive(int size) throws IOException {
        int bytesRead = 0;
        int offset = 0;
        byte[] readBuffer = new byte[size];

        while (bytesRead < size) {
            bytesRead += inputStream.read(readBuffer, offset, 
                                          (size - bytesRead));
            offset = bytesRead;
        }

        //System.out.println("bytesRead : " + bytesRead);

        return (bytesRead > 0) ? readBuffer: null;
    }

    public byte[] serialReceive() throws IOException {
        int bytesRead = 0;
        byte[] readBuffer = new byte[MAXSIZE];
        while (inputStream.available() > 0) {
            bytesRead = inputStream.read(readBuffer);
        }

        return (bytesRead > 0) ? readBuffer: null;
    }

}