edu.nps.util.comms

Class SerialIO

java.lang.Object

edu.nps.util.comms.SerialIO

All Implemented Interfaces:

Runnable, EventListener, javax.comm.SerialPortEventListener

public class SerialIO
extends Object
implements javax.comm.SerialPortEventListener, Runnable

Class declaration

Constructor Summary

Constructors

Constructor and Description
SerialIO() Default Ctor Creates an instance with default read buffer size of 1MB
SerialIO(int internalBufferSize) Ctor Creates an instance with read buffer size of internalBufferSize in bytes

Method Summary

Methods

Modifier and Type	Method and Description
void	close() close the serial connection
void	connect(PipedInputStream pipedInputStream) Connect a PipedInputStream to the PipedOutputStream to receive incoming data from the serial port
static String[]	getAvailableSerialPorts() Search for available commPorts on this machine e.g.
Logger	getLogger() Get the logger currently used by this class
void	ioctrl() IO control to comply with UNIX file IO.
static void	loadCommDriver(String driverName) Loads the comm driver manually on windows (if javax.comm is not installed properly in the JRE) [needs reference mailing-liist url here] On Windows: 1) win32com.dll to directory : YOUR_JDK/bin 2) javax.comm.properties to directory : YOUR_JDK/jre/lib 3) comm.jar to directory : YOUR_JDK/lib Other OS's: Load the OS specific shared library analog to the win32com.dll
void	open(String portName, int baudrate, int dataBits, int stopBits, int parity, boolean handshake) Opens the serial port with the specified parameters Note: make sure you call close() before reopening so the resources will be freed
int	read(byte[] readBuffer) Non-blocking read: Reads if data from the serial port is available.
int	read(byte[] readBuffer, int length) Blocking read: Read length data from the serial port.
void	run() Read Thread: wakes up every 20 seconds and will be interrupted by serialEvent (hopefully)
void	serialEvent(javax.comm.SerialPortEvent event) Method will be called by the java runtime, when a serial event of this serial port occurs.
void	write(byte[] writeBuffer) Non-blocking write

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

SerialIO

public SerialIO(int internalBufferSize)

Ctor Creates an instance with read buffer size of internalBufferSize in bytes

Parameters:

internalBufferSize -

SerialIO

public SerialIO()

Default Ctor Creates an instance with default read buffer size of 1MB

Method Detail

loadCommDriver

public static void loadCommDriver(String driverName)
                           throws Exception

Loads the comm driver manually on windows (if javax.comm is not installed properly in the JRE) [needs reference mailing-liist url here] On Windows: 1) win32com.dll to directory : YOUR_JDK/bin 2) javax.comm.properties to directory : YOUR_JDK/jre/lib 3) comm.jar to directory : YOUR_JDK/lib Other OS's: Load the OS specific shared library analog to the win32com.dll

Parameters:

driverName - on Windows this would be "com.sun.comm.Win32Driver"

Throws:

Exception

getAvailableSerialPorts

public static String[] getAvailableSerialPorts()

Search for available commPorts on this machine e.g. COM1, COM2 on win or /dev/term/a

Returns:

String[] to store the portNames

open

public void open(String portName,
        int baudrate,
        int dataBits,
        int stopBits,
        int parity,
        boolean handshake)
          throws Exception

Opens the serial port with the specified parameters Note: make sure you call close() before reopening so the resources will be freed

Parameters:

portName - portName of the SerialInterface e.g. COM1, COM2

baudrate - default baudrate

dataBits - number of databits: 7 or 8

stopBits -

parity - when 7 data bits, the 8th can be used for parity

handshake - sets handshake when transmitting data *

Throws:

Exception

close

public void close()

close the serial connection

read

public int read(byte[] readBuffer)

Non-blocking read: Reads if data from the serial port is available. If no data is available, it returns 0 and zero bytes will be written to readBuffer.length() If more data is available than readBuffer.length, it only reads readBuffer.length

Parameters:

readBuffer -

Returns:

number of bytes read

Throws:

IOException

NullPointerException

read

public int read(byte[] readBuffer,
       int length)

Blocking read: Read length data from the serial port. This method blocks until "length" data has arrived and puts it into the readBuffer.

Parameters:

readBuffer -

length -

Returns:

number of bytes read

Throws:

IOException

NullPointerException

ArrayIndexOutOfBoundsException

write

public void write(byte[] writeBuffer)

Non-blocking write

Parameters:

writeBuffer -

ioctrl

public void ioctrl()

IO control to comply with UNIX file IO. If we don't need it, we can throw it out. Right now this method is doing nothing. Seeunix file IO

getLogger

public Logger getLogger()

Get the logger currently used by this class

Returns:

Logger

connect

public void connect(PipedInputStream pipedInputStream)
             throws IOException

Connect a PipedInputStream to the PipedOutputStream to receive incoming data from the serial port

Parameters:

pipedInputStream -

Throws:

IOException

run

public void run()

Read Thread: wakes up every 20 seconds and will be interrupted by serialEvent (hopefully)

Specified by:

run in interface Runnable

serialEvent

public void serialEvent(javax.comm.SerialPortEvent event)

Method will be called by the java runtime, when a serial event of this serial port occurs. On DATA_AVAILABLE events, it will buffer data from the serial interface in its internal ringBuffer (In C this would be the ISR)

Specified by:

serialEvent in interface javax.comm.SerialPortEventListener

Parameters:

event -