Validating a JTextField having a float or double value.

Question

Hello,
I need help in validating a JTextfield which will accept a float or double value because it the deposit field and it shouldn't be of length more than 7 before the decimal and 2 after the decimal.That is it should be of length 10.I have written the following code for the validation.
txtDeposit.addKeyListener(new KeyAdapter(){
//Accept only integer value
          public void keyTyped(KeyEvent e){
          char c = e.getKeyChar();
if((txtDeposit.getText()).length() == 10)
          if (!(Character.isDigit(c)))
          if(!Character.isISOControl(c))
          getToolkit().beep();
          e.consume();
          });//end of txtDeposit*/
Please help.

Answer 1

use javax.swing.InputVerifier
import java.awt.BorderLayout;
import java.awt.Toolkit;
import javax.swing.InputVerifier;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JTextField;
public class VerifyInput extends JFrame {
    public VerifyInput(){
        super("Input Verifier");
        this.setSize(200, 200);
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        JTextField txt = new JTextField();
        txt.setInputVerifier(new CheckInput());
        this.getContentPane().add(txt, BorderLayout.NORTH);
        JButton btnMoveFocus = new JButton("CLick");
        this.getContentPane().add(btnMoveFocus, BorderLayout.SOUTH);
    public static void main(String[] args) {
        VerifyInput f = new VerifyInput();
        f.setVisible(true);
    class CheckInput extends InputVerifier{
        private int lengthBeforeDot = 7;
        private int lengthAfterDot = 2;
        public CheckInput(){
        public CheckInput(int lengthBeforeDot, int lengthAfterDot){
            this.lengthAfterDot = lengthAfterDot;
            this.lengthBeforeDot = lengthBeforeDot;
        public boolean verify(JComponent input) {
            boolean correct = true;
            try {
                JTextField tField = (JTextField) input;
                String text = tField.getText();
                if(text.length() == 0){
                    return true;
                if ((correct = isDoubleOrFloat(text))) {
                    correct = isFormatCorrect(text);
            } finally {               
                if(!correct){
                    Toolkit.getDefaultToolkit().beep();
                    System.out.println("Not Correct");
                }else{
                    System.out.println("Correct");
            return correct;
        private boolean isDoubleOrFloat(String text){
            try{
                Double.parseDouble(text);
            }catch(NumberFormatException nfe){
                return false;
            return true;
        private boolean isFormatCorrect(String text){
            int dotIndex = text.indexOf('.');
            if(dotIndex < 0){
                return text.length() <= lengthBeforeDot;
            String beforeDecimal = text.substring(0, dotIndex - 1);
            if(beforeDecimal.length() >= lengthBeforeDot){
                return false;
            String afterDecimal = text.substring(dotIndex + 1);
            if(afterDecimal.length() > lengthAfterDot){
                return false;
            return true;
}