code: @Override
  	public ValidationResult validate(FormCheckerElement elem) {
  		String value = elem.getValue();
  		ValidationResult vr = ValidationResult.ok();
  		if (value != null && !"".equals(value)) {
  			vr = allCriteriaSatisfied(elem);
  		} else {
  			// blank input is valid if it's not required
  			if (elem.isRequired()) {
  				vr = ValidationResult.fail("jformchecker.required", "");
  			} 
  		}
  		return vr;
  	}
docs: /*
  (non-Javadoc)
  
  @see de.jformchecker.validator.Validator#validate(de.jformchecker.
  FormCheckerElement)