@Override
    public ValidationResult validate(Object value) {
        if (value != null && value instanceof String && !((String) value).isEmpty())
            return new ValidationResult.ValidationPassed();
        else
            return new ValidationResult.ValidationFailed("Value \"" + value + "\" is not a valid non-empty String!");
    }
@Test
    public void testValidate() throws Exception {
        Validator v = new FilledStringValidator();
        assertFalse(v.validate(null).passed());
        assertFalse(v.validate(534).passed());
        assertFalse(v.validate("").passed());
        assertFalse(v.validate(new String()).passed());
        assertTrue(v.validate("so valid").passed());
    }