Custom constraint with dependencies

[enricosecondulfo]

Hello,
thank you so much for your great work, i need to validate a dto based on the presence or absence of an object contained within mongodb. In this case I need to inject a repository. How can I do this with yavi?

[making]

@enricosecondulfo Can you provide a sample code?

[enricosecondulfo]

I'm sorry to answer that now. I'll give you a very common example of a custom validation that I often use:

import javax.validation.Constraint;
import javax.validation.Payload;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Target({ElementType.FIELD})
@Retention(RetentionPolicy.RUNTIME)
@Constraint(validatedBy = NotExistsValidator.class)
public @interface NotExists {

    String message() default "already exists";

    Class<?>[] groups() default {};

    Class<? extends Payload>[] payload() default {};

    String parameter() default "";

    Class<?> clazz() default String.class;
}

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.mongodb.core.MongoOperations;
import org.springframework.data.mongodb.core.query.Criteria;
import org.springframework.data.mongodb.core.query.Query;

import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;

public class NotExistsValidator implements ConstraintValidator<NotExists, Object> {

    @Autowired
    private MongoOperations mongoOperations;

    private NotExists constraintAnnotation;

    @Override
    public void initialize(NotExists constraintAnnotation) {
        this.constraintAnnotation = constraintAnnotation;
    }

    @Override
    public boolean isValid(Object value, ConstraintValidatorContext context) {
        Criteria criteria = Criteria.where(this.constraintAnnotation.parameter()).is(value);
        return !this.mongoOperations.exists(new Query(criteria), this.constraintAnnotation.clazz());
    }
}

Thank your so much

[enricosecondulfo]

@making Can i archive this? Thank you

[making]

I think you can do if you define the validator in the constructor of the controller or service class after MongoOpearation injected

[enricosecondulfo]

@making Could you give me a practical example of how to create such a custom validation, please?

[making]

@enricosecondulfo

public class Foo {

    private final String id;

    public Foo(String id) {
        this.id = id;
    }

    public String getId() {
        return id;
    }
}

import am.ik.yavi.core.ConstraintViolations;
import am.ik.yavi.core.Validator;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.function.Function;

@RestController
public class FooController {

    private final FooService fooService;

    private final Validator<Foo> validator;

    public FooController(FooService fooService) {
        this.fooService = fooService;
        this.validator = Validator.<Foo>builder()
            .constraintOnObject(Function.identity(), "foo.id", c -> c.predicate(new FooCustomConstraint(this.fooService)))
            .build();
    }

    @PostMapping("/{id}")
    public Object post(@PathVariable("id") Foo foo) {
        return this.validator.validateToEither(foo)
            .fold(ConstraintViolations::details, x -> "OK");
    }
}

import am.ik.yavi.core.CustomConstraint;

public class FooCustomConstraint implements CustomConstraint<Foo> {

    private final FooService fooService;

    public FooCustomConstraint(FooService fooService) {
        this.fooService = fooService;
    }

    @Override
    public String messageKey() {
        return "foo.unique";
    }

    @Override
    public String defaultMessageFormat() {
        return "{0} must be unique.";
    }

    @Override
    public boolean test(Foo foo) {
        return !this.fooService.isExists(foo);
    }
}

import org.springframework.stereotype.Service;

@Service
public class FooService {

    public boolean isExists(Foo foo) {
        return "1".equals(foo.getId());
    }
}

[enricosecondulfo]

@making thank you a lot, the example is very clear and exhaustive

[making]

You're welcome