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import java.awt.BorderLayout;
import javax.swing.InputVerifier;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JTextField;
import javax.swing.text.JTextComponent;
public class AddingActionCommandActionListenerSample {
public static void main(String args[]) {
final JFrame frame = new JFrame("Default Example");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JTextField textField = new JTextField();
frame.add(textField, BorderLayout.NORTH);
frame.add(new JTextField(), BorderLayout.SOUTH);
InputVerifier verifier = new InputVerifier() {
public boolean verify(JComponent input) {
final JTextComponent source = (JTextComponent)input;
String text = source.getText();
if ((text.length() != 0) && !(text.equals("Exit"))) {
JOptionPane.showMessageDialog (frame, "Can't leave.",
"Error Dialog", JOptionPane.ERROR_MESSAGE);
return false;
} else {
return true;
}
}
};
textField.setInputVerifier(verifier);
frame.setSize(250, 150);
frame.setVisible(true);
}
}
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