Unix terminal in java

Question

Hi all, I am working on a project which will allow a person to be working on code and have other users sign in and post comments to there code to help them with problems. One of the features I wanted to have is a terminal windows in which the user could compile and run their code and allow other users to view the output. I was going to just have a compile and run button and show the output using runtime.exec(<java or javac>) but I though it would be much more useful to have a full terminal window. So far I am able to run runtime.exec(�tcsh -i�) in a text area and have it process the text typed. The problem, I have is that the command prompt only show up when it executes a command that has output and executes correctly (for example ls). With a simple return or cd it will not output a command prompt until I do something like an ls again, in that case it will output as many prompts as I have hit returns. I would like it to work as closely to as possible to any gome-terminal or like terminal that we all use daily. Any help you be greatly appreciated, thank a lot in advance.
Kyle
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
public class JavaTerminal extends JPanel {
    TextArea ta;
    InputStream in;
    InputStream err;
    OutputStream out;
    public JavaTerminal() { //throws IOException {
        try {
            String[] envp = null;
            File dir = new File(".");
            Process p = Runtime.getRuntime().exec("tcsh -i", envp, dir);
            in = p.getInputStream();
            err = p.getErrorStream();
            out = p.getOutputStream();
        } catch (IOException e) {
            System.err.println("Cannot create JavaTerminal: " + e);
            e.printStackTrace();
            System.exit(-1);
        ta = new TextArea(24,70);
        setLayout(new BorderLayout());
        add(ta, BorderLayout.CENTER);
        ta.addKeyListener(new KeyListener() {
            PrintWriter  pw = new PrintWriter(new OutputStreamWriter(out));
            public void keyPressed(KeyEvent e) { }
            public void keyReleased(KeyEvent e) {
                char text = e.getKeyChar();
                System.out.println(text);
                pw.print(text);
                pw.flush();
            public void keyTyped(KeyEvent e) { }
        (new Thread(new Runnable() {
            public void run() {
                BufferedReader br = new BufferedReader(new InputStreamReader(in));
                String line = null;
                int b;
                try {
                    while((line = br.readLine()) != null) {
                        ta.append(line + "\n");
                } catch (IOException e) {
                    ta.append("IOException reading stdout: " + e);
                    e.printStackTrace();
        })).start();
        (new Thread(new Runnable() {
            public void run() {
                BufferedReader br = new BufferedReader(new InputStreamReader(err));
                String line = null;
                try {
                    while((line = br.readLine()) != null) {
                        ta.append(line + "\n");
                } catch (IOException e) {
                    ta.append("IOException reading stderr: " + e);
                    e.printStackTrace();
        })).start();
    public static void main(String[] argv) {
        Frame f = new Frame("Java Terminal");
        f.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
                System.exit(0);}
        JavaTerminal jt = new JavaTerminal();
        f.add(jt, BorderLayout.CENTER);
        f.pack();
        f.setVisible(true);
}

Answer 1

Well I solved the problem I was having. Apparently you can not buffer the input and output streams of a process, and I also believe the input and output must be of the same type of stream, or at least the same encoding, which makes sense. Now just to figure out how to restrict the caret position and how to handle back space and other special keys for a fully functional unix terminal in a JPanel. Thanks to any one who read my post and tried to figure it out. I am posting my corrected code so far for other who would like to try something like this. Any suggestions on how to handle my next few problems would be appreciated as well.
Kyle
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
public class JavaTerminal extends JPanel {
    TextArea ta;
    InputStream in;
    InputStream err;
    OutputStream out;
    public JavaTerminal() {
        ta = new TextArea(24,70);
        setLayout(new BorderLayout());
        add(ta, BorderLayout.CENTER);
        try {
            String[] envp = null;
            File dir = new File(".");
            Process p = Runtime.getRuntime().exec("tcsh -i", envp, dir);
            in = p.getInputStream();
            err = p.getErrorStream();
            out = p.getOutputStream();
        } catch (IOException e) {
            ta.append("IOException getting streams: " + e);
            e.printStackTrace();
        ta.addKeyListener(new KeyListener() {
            OutputStreamWriter osw = new OutputStreamWriter(out);
            public void keyPressed(KeyEvent ke) { }
            public void keyReleased(KeyEvent ke) {
                char text = ke.getKeyChar();
                try {
                    osw.write(text);
                    osw.flush();
                } catch (IOException e) {
                    ta.append("IOException writeing stdout: " + e);
                    e.printStackTrace();
            public void keyTyped(KeyEvent ke) { }
        (new Thread(new Runnable() {
            public void run() {
                InputStreamReader isr = new InputStreamReader(in);
                int i;
                try {
                    while((i = isr.read()) != -1) {
                        ta.append(String.valueOf((char)i));
                } catch (IOException e) {
                    ta.append("IOException reading stdin: " + e);
                    e.printStackTrace();
        })).start();
        (new Thread(new Runnable() {
            public void run() {
                InputStreamReader isr = new InputStreamReader(err);
                int i;
                try {
                    while((i = isr.read()) != -1) {
                        ta.append(String.valueOf((char)i));
                } catch (IOException e) {
                    ta.append("IOException reading stderr: " + e);
                    e.printStackTrace();
        })).start();
    public static void main(String[] argv) {
        Frame f = new Frame("Java Terminal");
        f.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
                System.exit(0);}
        JavaTerminal jt = new JavaTerminal();
        f.add(jt, BorderLayout.CENTER);
        f.pack();
        f.setVisible(true);
}