public boolean handleEvent(ValidationEvent event) {

    if (event == null) {
      throw new IllegalArgumentException();
    }

    // calculate the severity prefix and return value
    String severity = null;
    boolean retVal = false;
    switch (event.getSeverity()) {
      case ValidationEvent.WARNING:
        severity = Messages.format(Messages.WARNING);
        retVal = true; // continue after warnings
        break;
      case ValidationEvent.ERROR:
        severity = Messages.format(Messages.ERROR);
        retVal = false; // terminate after errors
        break;
      case ValidationEvent.FATAL_ERROR:
        severity = Messages.format(Messages.FATAL_ERROR);
        retVal = false; // terminate after fatal errors
        break;
      default:
        assert false : Messages.format(Messages.UNRECOGNIZED_SEVERITY, event.getSeverity());
    }

    // calculate the location message
    String location = getLocation(event);

    System.out.println(
        Messages.format(Messages.SEVERITY_MESSAGE, severity, event.getMessage(), location));

    // fail on the first error or fatal error
    return retVal;
  }
  /** Calculate a location message for the event */
  private String getLocation(ValidationEvent event) {
    StringBuffer msg = new StringBuffer();

    ValidationEventLocator locator = event.getLocator();

    if (locator != null) {

      URL url = locator.getURL();
      Object obj = locator.getObject();
      Node node = locator.getNode();
      int line = locator.getLineNumber();

      if (url != null || line != -1) {
        msg.append("line " + line);
        if (url != null) msg.append(" of " + url);
      } else if (obj != null) {
        msg.append(" obj: " + obj.toString());
      } else if (node != null) {
        msg.append(" node: " + node.toString());
      }
    } else {
      msg.append(Messages.format(Messages.LOCATION_UNAVAILABLE));
    }

    return msg.toString();
  }