class SpdxExpressionValidator implements ConstraintValidator<ValidSpdxExpression, String> {

    @Override
    public boolean isValid(final String expressionString, final ConstraintValidatorContext validatorContext) {<FILL_FUNCTION_BODY>}

}

        if (expressionString == null) {
            // null-ness is expected to be validated using @NotNull
            return true;
        }

        return !Objects.equals(new SpdxExpressionParser().parse(expressionString), SpdxExpression.INVALID);
    
<no_super_class>