// RegexFormatter.java

package javaapplication;

import java.text.*;
import java.util.regex.*;
import javax.swing.text.*;

public class RegexFormatter extends DefaultFormatter {

  private Pattern pattern;
  private Matcher matcher;

  public RegexFormatter() {
    super();
  }

  public RegexFormatter(String regex) throws PatternSyntaxException {
    this();
    setPattern(Pattern.compile(regex));
  }

  public RegexFormatter(Pattern pattern) {
    this();
    setPattern(pattern);
  }

  public void setPattern(Pattern pattern) {
    this.pattern = pattern;
  }

  public Pattern getPattern() {
    return pattern;
  }

  protected void setMatcher(Matcher matcher) {
    this.matcher = matcher;
  }

  protected Matcher getMatcher() {
    return matcher;
  }

  @Override
  public Object stringToValue(String text) throws ParseException {
    Pattern p = getPattern();

    if (p != null) {
      Matcher m = p.matcher(text);

      if (m.matches()) {
        setMatcher(m);
        return super.stringToValue(text);
      }
      throw new ParseException("Pattern did not match", 0);
    }
    return text;
  }
}