Thoughts(PoC) kind of DSL (JavaScript) for data validation on POJO'less Java backend.
Here is an example of field metadata:
{
"name": "integerField",
"type": "INTEGER",
"validator": "decimalMin({value: '0'}) && decimalMax({value: '10'}) && exact5()"
}Field "validator" contains a mixture of JSR-303 validation constraints and user validator 'exact5'. The 'exact5' validator was implemented as following javascript function:
function exact5(message){
if (currentFieldValue != '5') {
if(typeof message === 'undefined'){
message = "Values must be exactly '5'";
}
__validator.addViolation('t', message, null);
return false;
}
return true;
}This JS function uses two of three implicit objects which are currently available in JS context as global vars:
- __validator - corresponding instance of Validator which performs validation;
- current Field - metadata for a validating field;
- currentFieldValue - value which is currently validated.
Entity validation might be performed as follows:
final EntityInfo ei;
final String exact5str // <-- place JS
AbstractValidator validator = new HibernateValidator(){
@Override
protected void onInit() throws Exception {
super.onInit();
registerScript(exact5str);
}
};
final Set<ConstraintViolation> violations = validator.validate(ei, (Map<String, Object>) values);
if(violations != null){
// Something invalid
}You can find more examples in ProofOfUsageFieldValueValidationScenariosTest.java