Reading a char array from Serial port

Question

Need help!
Hi, I've got the following problem - I wanna read a input stream from serial port and I use at the moment the following method (reading bytewise):
public String receiveText (){
      byte ch;
      fStrBuf.delete(0,fStrBuf.length()); //clearing the buffer
try{
          do {
          ch = (byte) fPortInStream.read();
          fStrBuf.append( (char) ch);
        while ( (byte) ch != 0x03); //The end of frame byte
         }catch(IOException ioe) {};
      return fStrBuf.toString();It works pretty well, but disadvantage is that it's too slow to use it in the thread (at least I think so)
How can I change it to read all available data from the port (or simply faste). I don't need event listeners, because it's a request-responde communication.
I tried smth. like this
byte[] readBuffer = new byte[20];
            try {
                while (fPortInStream.available() > 0) {
                    int numBytes = inputStream.read(readBuffer);
                    fStrBuf.append(readBuffer);
            } catch (IOException e) {}
      return fStrBuf.toString();But it doesn't seem to work :-(

Answer 1

May I suggest that you use StringBuilder rather than StringBuffer. It has less overhead because it is not threadsafe. I do synchronous serial port stuff with Opto 22, and i have no listeners enabled.
Appending to the String(Builder/Buffer) directly from the byte buffer mangles it. So I use a string (ugh). With the Opto22 brain boards, i am looking for a carriage return as a term char. It either finds it or times out.
This is the best i have come up with so far:
StringBuilder response = new StringBuilder();
String data = new String();
long msTimeOut = 2000;
public void getResponse () throws IOException {
        byte[] readBuff = {0};
        int charAvail;
        response.delete(0,response.length());
        long ts = Calendar.getInstance().getTimeInMillis();
        try {
            while ( readBuff[readBuff.length-1] != '\r' ) {
                charAvail = inputStream.available();
                if ( charAvail > 0 ) {
                    readBuff = new byte[charAvail];
                    inputStream.read(readBuff);
                    response.append(new String(readBuff));
                if ( Calendar.getInstance().getTimeInMillis() > (ts + msTimeOut) ) {
                    response.delete(0,response.length());
                    response.append("TIMEOUT");
                    break;
        } catch (IOException e) { e.printStackTrace(); throw e; }        
        data = response.substring(0);
    } I just starting writing Java about 4 days ago, so caveat emptor.