Java Swing How to - Handle focus lost and document event for JFormattedTextField

Question

We would like to know how to handle focus lost and document event for JFormattedTextField.
Answer

import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.event.FocusEvent;
import java.awt.event.FocusListener;
import java.math.RoundingMode;
import java.text.NumberFormat;
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import javax.swing.JFormattedTextField;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingConstants;
import javax.swing.border.EmptyBorder;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;

public class Main {
  JFrame frame = new JFrame();
  JPanel pnl = new JPanel();
  JLabel focusLabel = new JLabel(" focusLost Handle ");
  JFormattedTextField formTextField;
  JLabel docLabel = new JLabel(" document Handle ");
  JFormattedTextField formTextField1;
  NumberFormat formTextFieldFormat;
  double amount = 10000.00;

  public Main() {
    formTextFieldFormat = NumberFormat.getNumberInstance();
    formTextFieldFormat.setMinimumFractionDigits(2);
    formTextFieldFormat.setMaximumFractionDigits(2);
    formTextFieldFormat.setRoundingMode(RoundingMode.HALF_UP);

    focusLabel.setPreferredSize(new Dimension(120, 27));
    formTextField = new JFormattedTextField(formTextFieldFormat);
    formTextField.setValue(amount);
    formTextField.setPreferredSize(new Dimension(120, 27));
    formTextField.setHorizontalAlignment(SwingConstants.RIGHT);
    formTextField.addFocusListener(new FocusListener() {

      @Override
      public void focusGained(FocusEvent e) {
        formTextField.requestFocus();
        formTextField.setText(formTextField.getText());
        formTextField.selectAll();
      }

      @Override
      public void focusLost(FocusEvent e) {
        double t1a1 = (((Number) formTextField.getValue()).doubleValue());
        if (t1a1 < 1000) {
          formTextField.setValue(amount);
        }
      }
    });

    docLabel.setPreferredSize(new Dimension(120, 27));

    formTextField1 = new JFormattedTextField(formTextFieldFormat);
    formTextField1.setValue(amount);

    formTextField1.setHorizontalAlignment(SwingConstants.RIGHT);
    formTextField1.addFocusListener(new FocusListener() {

      @Override
      public void focusGained(FocusEvent e) {
        formTextField1.requestFocus();
        formTextField1.setText(formTextField1.getText());
        formTextField1.selectAll();
      }

      @Override
      public void focusLost(FocusEvent e) {
      }
    });
    formTextField1.getDocument().addDocumentListener(docListener);

    pnl = new JPanel();
    pnl.setBorder(new EmptyBorder(2, 2, 2, 2));
    pnl.setLayout(new GridLayout(2, 2));
    pnl.add(focusLabel);
    pnl.add(formTextField);
    pnl.add(docLabel);
    pnl.add(formTextField1);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.add(pnl, BorderLayout.CENTER);
    frame.setLocation(200, 200);
    frame.pack();
    frame.setVisible(true);
    formTextFieldFocus1();
  }

  DocumentListener docListener = new DocumentListener() {
    @Override
    public void changedUpdate(DocumentEvent documentEvent) {
      printIt(documentEvent);
    }

    @Override
    public void insertUpdate(DocumentEvent documentEvent) {
      printIt(documentEvent);
    }

    @Override
    public void removeUpdate(DocumentEvent documentEvent) {
      printIt(documentEvent);
    }

    void printIt(DocumentEvent documentEvent) {
      DocumentEvent.EventType type = documentEvent.getType();
      double t1a1 = (((Number) formTextField1.getValue()).doubleValue());
      if (t1a1 < 100) {

        formTextField1.setValue(amount);

      }
    }
  };

  void formTextFieldFocus1() {
    formTextField1.grabFocus();
    formTextField1.requestFocus();
    formTextField1.setText(formTextField1.getText());
    formTextField1.selectAll();

  }

  void formTextFieldFocus() {
    formTextField.grabFocus();
    formTextField.requestFocus();
    formTextField.setText(formTextField.getText());
    formTextField.selectAll();
    formTextFieldFocus1();
  }

  public static void main(String args[]) {
    Main fl = new Main();
  }
}