How to auto complete text field

Question

Hello!
I have the following behavior request for a text field.
An user must write a date in a text field. The date format is yyyy/MM/dd (as 2003/02/04). The user would begin writing "2003" followed by the "0" character but would see in the text field "2003/0". The "/" would be automagically putted there.
I hope this table will make the behavior more clear.
User User
writes sees this in the text field.
2003 2003
20030 2003/0
200302 2003/02
2003020 2003/02/0
20030201 2003/02/01
Also, if the user deletes the characters "1" and next the "0" from the previous example, it would automatically erase also the "/" character.
Could someone point me to some sample code or give me some clues how to implement the previous behaviour? Does this pattern behavior has some well know name, where I can "google" for?
Thanks!
Eduardo

Answer 1

Hello!
I found a solution for my request feature, explained above.
Maybe someone will find it also usefull.
Regards,
Eduardo
public class JFormattedDateTextField extends JFormattedTextField {
Format _formatDt = new SimpleDateFormat("yyyy/MM/dd");     
public JFormattedDateTextField() {
     super();
     MaskFormatter mformat = null;
     try {
          mformat = new MaskFormatter("####/##/##");
     } catch (ParseException e1) {
          e1.printStackTrace();
     mformat.setPlaceholderCharacter('_');
     setFormatterFactory(new DefaultFormatterFactory(mformat));
     this.addFocusListener(new FocusAdapter() {
          public void focusGained(FocusEvent e) {
               if (getFocusLostBehavior() == JFormattedTextField.PERSIST)
                    setFocusLostBehavior(JFormattedTextField.COMMIT_OR_REVERT);
          public void focusLost(FocusEvent e) {
               try {
                    Date dt = (Date) _formatDt.parseObject(getText());
                    setValue(_formatDt.format(dt));
               } catch (ParseException pe) {
                    setFocusLostBehavior(JFormattedTextField.PERSIST);
                    setText("");
public void setValue(Date strDt) {
     super.setValue(convertDateToStr(strDt));
public Date getDateValue() {
     return convertStrToDate((String)super.getValue());
public EFADateValue getEFADate() {
     return new EFADateValue(getDateValue());
private Date convertStrToDate(String txt) {
     Date date = null;
     if (txt == null) return null;
     try {
          date = (Date)_formatDt.parseObject(txt);
     catch (ParseException pe) {
          date = null;
     return date;
private String convertDateToStr(Date date) {
     try {
          return _formatDt.format(date);
     } catch (Exception e) {
          return "";