http://rxtx.qbang.org/wiki/index.php/Event_Based_Two_Way_Communicationから改変されたコード
SerialReader クラスを使用して共通バッファーを読み取り、そのバッファーを SerialWriter クラスを介してシリアル経由で送信しようとしていますが、Writer が呼び出されるたびにバッファーが null として表示されます。コードは、TwoWaySerialCommTest の connect メソッドを使用して初期化されます (参考のために以下に貼り付けます)。
public SerialWriter ( OutputStream out )
{
this.out = out;
}
public SerialWriter ( OutputStream out, byte[] buffer)
{
this.out = out;
this.buffer = buffer;
}
public void run ()
{
while(true)
{
lock.lock();
try
{
dataAvailable.await();
System.out.println("Waking up");
int i = 0;
if (this.buffer != null)
{
System.out.println("Buffer isn't empty");
while(buffer[i] != ((byte)'\n') && i < buffer.length - 1)
{
this.out.write(buffer[i]);
}
}
else
{
System.out.println("Buffer is null");
System.out.println(this.buffer.toString());
}
}
catch ( IOException e )
{
e.printStackTrace();
System.exit(-1);
}
catch(Exception e)
{
e.printStackTrace();
}
finally
{
lock.unlock();
}
}
}
}
シリアルリーダークラス
public static class SerialReader implements SerialPortEventListener
{
private InputStream in;
byte[] buffer;
public SerialReader ( InputStream in )
{
this.in = in;
}
public SerialReader (InputStream in, byte[] buffer)
{
this.in = in;
this.buffer = buffer;
}
public void serialEvent(SerialPortEvent arg0) {
lock.lock();
int data;
if (buffer != null)
{
for(int i = 0; i < buffer.length; i++)
{
if (buffer[i] != 0)
{
System.out.print((char)buffer[i]);
}
}
}
buffer = new byte[1024];
try
{
int len = 0;
while ( ( data = in.read()) > -1 )
{
if ( data == '\n' ) {
break;
}
buffer[len++] = (byte) data;
}
System.out.println(new String(buffer,0,len));
for(int i = 0; i < buffer.length; i++)
{
if (buffer[i] != 0)
{
System.out.print((char)buffer[i]);
}
}
System.out.println();
dataAvailable.signal();
}
catch ( IOException e )
{
e.printStackTrace();
System.exit(-1);
}
finally
{
lock.unlock();
}
}
}
TwoWaySerialCommTest (切り捨て)
import gnu.io.SerialPortEvent;
import gnu.io.SerialPortEventListener;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.concurrent.locks.*;
/**
* This version of the TwoWaySerialComm example makes use of the
* SerialPortEventListener to avoid polling.
*
*/
public class TwoWaySerialCommTest
{
static Lock lock = new ReentrantLock();
static Condition dataAvailable = lock.newCondition();
public volatile byte[] buffer;
public TwoWaySerialCommTest()
{
super();
}
void connect ( String portName ) throws Exception
{
CommPortIdentifier portIdentifier = CommPortIdentifier.getPortIdentifier(portName);
if ( portIdentifier.isCurrentlyOwned() )
{
System.out.println("Error: Port is currently in use");
}
else
{
CommPort commPort = portIdentifier.open(this.getClass().getName(),2000);
if ( commPort instanceof SerialPort )
{
SerialPort serialPort = (SerialPort) commPort;
serialPort.setSerialPortParams(57600,SerialPort.DATABITS_8,SerialPort.STOPBITS_1,SerialPort.PARITY_NONE);
InputStream in = serialPort.getInputStream();
OutputStream out = serialPort.getOutputStream();
(new Thread(new SerialWriter(out , buffer))).start();
serialPort.addEventListener(new SerialReader(in , buffer));
serialPort.notifyOnDataAvailable(true);
}
else
{
System.out.println("Error: Only serial ports are handled by this example.");
}
}
}