JTextField max length, JTextArea automatic scrolling

Question

i cant find how to do 2 things,
i would like to limit the size of the text entered in a JTextField
i could probably do this by making its KeyListener trim off the extra from getText() and use setText(whateverIsLeft) but i was hoping there was a better way of doing this with something that is already there as this is a lot of work considering soemoen could just hold down a button and it would have to do it several times a second
also i need to set a JTextArea inside a JScrollPane so that when new text is appended to it, it scrolls the jtextpane down to the bottom, i could just make it write it at the top instead of appending it to the bottom but i REALLY dont want to =p
thanks

Answer 1

i've got the same probelm with the JSrollPane
this is what i usually do
public void keyPressed(KeyEvent e) {
if (e.getKeyCode() == KeyEvent.VK_ENTER) {
ta.setText(ta.getText() + "\n" + tf.getText());
tf.setText("");
jsp.setPreferredSize(new Dimension(0, 0));
jsp.revalidate();
where tf is a JTextField, ta is a JTextArea and jsp is the JScrollPane in which ta is added
this worked great so far but when i try to set it through this
BufferedReader in = new BufferedReader(
new InputStreamReader(port.getInputStream()));
it just refuses to work and i haven't got the slightest clue why ...
here is the Thred i use :
private class Reciever extends Thread {
private BufferedReader in = null;
private String change = "";
public String getChange() {
return change;
public Reciever() {
Socket port = conMan.getPort();
try {
in = new BufferedReader(new InputStreamReader(port.getInputStream()));
} catch (IOException e) {
e.printStackTrace();
System.err.println("[system] : I/O Exception ");
} catch (NullPointerException e) {
e.printStackTrace();
System.err.println("[system] : Null Pointer Exception ");
start();
public void run() {
for (; ;) {
try {
change = in.readLine();
setText(change);//this is the method that sets the text in the JTextArea
} catch (SocketException e) {
Main.getStatus().setMsg("Closed " + conMan.getPort());
return;
} catch (IOException e2) {
e2.printStackTrace();
return;
and the setText(); method :
public void setText(String txt) {
if (txt != null && !txt.equals(null) && !txt.equals("")) {
receive.setText(receive.getText() + "\n" + txt);
i tryed all of the above ways nothing works so far ...