I'm using javax.validation to validate my domain objects. Now I like to validate some fields that are not annotated with any Constraints. The use case is to disallow some characters in all strings w/o the need to annotate all of them and to make this automatically work with future extensions.
Is it possible to plug in a validator implementation that is called e.g. for all properties of my #Valid-annotated beans, in which I can check for applicability and validity?
Related
I'm using the Spring LDAP (docs) library in a Grails application. I have a class annotated with the #Entry annotation, so it is mapped to an LDAP server. This all works quite beautifully.
However, when I add the Grails #Validateable annotation (to enable validating the LDAP class similarly to Grails domain classes) and attempt to retrieve data from LDAP (i.e. a findAll operation on the LdapUserRepo, or similar), I get the following exception:
Message: Missing converter from class java.lang.String to interface org.springframework.validation.Errors, this is needed for field errors on Entry class com.ldap.portal.LdapUser
Basically, it seems like the AST transformation performed by the #Validateable annotation is producing extra fields (namely the errors field) on the LdapUser object. It appears that Spring LDAP, in processing the #Entry logic, assumes a default mapping for the fields property (probably interpreting it as a string field on the LDAP object). When it gets nothing from the LDAP server, it attempts to set the field of type ValidationErrors to a value of type String -- an empty string.
I did some looking in github and found this code that seems relevant and may support my theory.
My question is: is this behavior expected for annotations, and how can one prevent fields added by one annotation from being inappropriately processed by another annotation?
At present the best workaround I've come up with for my specific issue is to add an errors field to my LdapUser object and mark it as transient (so that LDAP ignores it):
#Transient
ValidationErrors errors
What are my options to do output validation of entities in Jersey? Simple use case would be to validate that a returned User instance doesn't have a certain field set to non-null.
Not sure of the context, it this at runtime, or during unit tests?
Bean Validation is one very popular validation framework.
You can readily use it to validate your input (see #NotNull, #Valid and other bean validation annotations with Jersey) ref : https://jersey.java.net/documentation/latest/bean-validation.html
If you want to validate your output, you can use the bean validation framework also, but you will need to use it manually and handle errors.
just check out one of many tutorials on bean validation : http://java.dzone.com/articles/bean-validation-made-simple
I want to use JSR 303 (Hibernate Validator) in my JSF 2 project. However, I have complicated forms and field-level validation is not sufficient. I need to use many #ScriptAssert annotations at class-level of my model and its child beans.
So I want to validate form models manually (inside bean action method for example). But I could not understand how I can preserve which validation message should be shown at which field (as it works automatically when field-level validation is on and processed by JSF).
Also I'll need to specify for some of class-level annotations that their messages are to be shown at specific fields. I do not see a straight way to manage it...
Could you please provide a link to explanations of these questions (or tell me that I am doing something wrong?). I think I fail in googling it because internet is bloating with keywords JSF and validation, sorry.
The most idiomatic way to do that is to create custom Bean Validation validator for your class.
You need to create validation annotiation that you would put at the class level (not field level) and associated with that class validator class.
See for instance:
http://docs.jboss.org/hibernate/validator/4.1/reference/en-US/html/validator-usingvalidator.html (Example "Class level constraint")
How can I validate two or more fields in combination?
Validation inside managed bean is also possible, you can throw in your action methods proper validation exception, but usually it is cumbersome, hard to reuse and mixes business logic code with validation.
I'm just wondering about data validation in Spring. Spring is offering two (maybe more) validation options. First option is to use Validator interface and create whole validation on my own. Second option is to use annotation validation (JSR 303).
And now I'm really confused :) which validation I should chose. What I need is to check if recieved Data Object is correct (by correct i mean all required fields are filled) and this can be done by JSR 303 validation or by my own validator with "Validator instance". But I also need to check if is this Data Object valid against some database constraints (validator is required to check some data in database, eq. is user with this ID registered or not ...) and this can be done only by my own validator.
I don't know which way should be the best. Combine both or create my own validator ?
I will be thankful for any advice ...
Update (relocated from comments)
Ok, I followed Ryan's example and I think I was successful. I created my own implementation of spring Validator and in this Validator I #Autowire-d javax JSR 303 instance. But there was problem with that injection. I had in my configuration and this piece of code caused some exceptions, because spring did not know which Validator I want to inject. So I removed that code.
At the end I also removed the spring Validator implementation, because I dont know where I can get Errors property, which is required as second parameter in "validate" method :). I'm triggering that validation manually from service layer and I really don't know, where I can obtain that Error object.
BTW Well, I found another solution how to implement that validation. I'm thinking about to extend my validator class by LocalValidatorFactoryBean. LocalValidatorFactoryBean class implementing both Validator interfaces (Spring Validator + JSR 303). But i'm not sure if is this good approach. This approach also require Error object, which I don't know where to find/get.
Update
The Error object is coming from "BindException".
FooObjectVO myObject = new FooObjectVO();
BindException errors = new BindException("fooObject", myObject);
They're not really separate options--more like two available implementations of validation. Since Spring's JSR 303 support also implements its own Validator interface, you don't really have to pick one or the other. You can mix and match the implementations in whatever way makes it easiest to get the job done.
In cases such as this I prefer to combine both. I like to use JSR 303 validation for whatever I can. I supplement it with my own validators.
i have a login-validation.xml which define some basic field validation rules.
however that's not enough for me.
i need to do some more database lookup and i consider this as part of my validation logic.
how can i do both xml validation and my database lookup in one go?
i suppose i will write something like
public void validate() {
1) struts2-validation.xml validation();
2) myDatabaseLookup() and addFieldError() or addActionError();
}
my problem is, what is the api i can use for (1)?
or, how can i look at the code of this xml validation filter class? in fact i would also make the definitions in validation.xml available to javascript usage... i guess i would need to do some translation from xml to javascript logic, but first of all, how can i access the validation.xml api in java code?
Your best choice is to create a validator... Take a look here for some information -
Custom Validator
There are a few things to keep in mind... I don't know if the ObjectFactory will instantiate and inject your validator, so you might not have all the features of dependency injection. If your custom validator isn't injected, file a bug, I'll take a look at it.
After you create your validator and register it in your app, you can add it to the validation.xml file.
(side note, I know that I am pointing to the XWork docs, but Struts2 uses XWork internally for most of it's validation capabilities)