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| import java.awt.EventQueue;
import java.awt.FlowLayout;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.border.EmptyBorder;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;
import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.PlainDocument;
public class test extends JFrame
{
private JPanel contentPane;
private JTextField textField;
private JTextField textField_1;
/**
* Launch the application.
*/
public static void main(String[] args)
{
EventQueue.invokeLater(new Runnable()
{
public void run()
{
try
{
test frame = new test();
frame.setVisible(true);
} catch (Exception e)
{
e.printStackTrace();
}
}
});
}
/**
* Create the frame.
*/
public test()
{
initialize();
}
private void initialize() {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setBounds(100, 100, 450, 300);
contentPane = new JPanel();
contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
setContentPane(contentPane);
contentPane.setLayout(new FlowLayout(FlowLayout.CENTER, 5, 5));
contentPane.add(getTextField());
contentPane.add(getTextField_1());
}
private JTextField getTextField() {
if (textField == null) {
final int limit = 4;
textField = new JTextField();
textField.setDocument(new PlainDocument()
{
@Override
public void insertString(int offset, String str, AttributeSet attr) throws BadLocationException {
if (str == null)
return;
if ((getLength() + str.length()) <= limit) {
super.insertString(offset, str, attr);
}
else {
System.err.println("Focus on other field");
textField_1.requestFocus();
textField_1.selectAll();
}
}
});
textField.setColumns(10);
}
return textField;
}
private JTextField getTextField_1() {
if (textField_1 == null) {
textField_1 = new JTextField();
textField_1.setColumns(10);
}
return textField_1;
}
} |
