Problem while reading data from Serial Port

Question

Hi All,
I am facing some problem while reading data from Serial Port.
As per the requirement I am writing the data on Serial Port and waiting for response of that data.
Notification for data availabilty is checked with method public void serialEvent(SerialPortEvent event) of javax.comm.SerialPortEventListener.
When we are writing data on the port one thread i.e. "main" thread is generated and when data availability event occures another thread "Win32SerialPort Notification thread" is generated. This creates problem for me as we can't control thread processing.
So can anybody pls explain me how to overcome this problem?
Regards,
Neha

Answer 1

My Problem is:-
I am simoultaneouly wrting data on port & reading data from port.
First I write data on port using outputStream.write() method. Now when target side sends me response back for the request on serial port DATA_AVAILABLE of SerialPortEventListner event occured,we are reading data from serial port.Now till the time we didn't get the response from target next command can't be written on the serial port. When we are writing data on port main thread is executed.Now my problem starts when DATA_AVAILABLE event occured.At this point another thread is created.Due to this my program writes data of next command without reading response of previous command.To solve this prob. I have used wait() & notify() methods as follows.But again due to this my pc hangs after execution of 2 commands. (PC hang in while loop in a code provided below.)
From SOPs I could figure it out that after 2 commands we are not able to write data on serial port so DATA_AVAILABLE event doesn't occure n pro. goes in wait state.
Can anybody help me to solve this issue.
Neha.
Code:
public void serialEvent(SerialPortEvent event)
          switch (event.getEventType())
               case SerialPortEvent.BI:
               case SerialPortEvent.OE:
               case SerialPortEvent.FE:
               case SerialPortEvent.PE:
               case SerialPortEvent.CD:
               case SerialPortEvent.CTS:
               case SerialPortEvent.DSR:
               case SerialPortEvent.RI:
               case SerialPortEvent.OUTPUT_BUFFER_EMPTY:
                             break;
               case SerialPortEvent.DATA_AVAILABLE:
                    try
                         dataThread = Thread.currentThread();
                         dataThread.setPriority(10);
                         dataAvailable = true;
                                                                                byte[] tempArray=new byte[availableBytes];
                                    inputStream.read(tempArray);
                                                                   catch (IOException io)
                         SOP(io, "Error in serialEvent callback call for event DATA_AVAILABLE");
public void  writetoPort(byte[] data) throws IOException
                         outputStream.write(data);
                          while(finalTimeOut >= actualTime)
                        if( ! dataAvailable)
                                actualTime = System.currentTimeMillis();
                       else
          synchronized (mainThread)
               mainThread = Thread.currentThread();
               mainThread.wait();
public  void sendDatatoUser(byte[] b) throws Exception, HWCCSystemFailure
          obj.returnData(b);
          synchronized(mainThread)
               mainThread.notify();