Why hibernate validator

A validator can also optionally apply the constraint to the Hibernate metamodel, allowing Hibernate to generate DDL that expresses the constraint. With the appropriate event listener, you can execute the checking operation on inserts and updates done by Hibernate.

Hibernate Validator is not limited to use with Hibernate. You can easily use it anywhere in your application. When checking instances at runtime, Hibernate Validator returns information about constraint violations in an array of InvalidValue s. Among other information, the InvalidValue contains an error description message that can embed the parameter values bundle with the annotation eg. A constraint is represented by an annotation. A constraint usually has some attributes used to parameterize the constraints limits.

The constraint apply to the annotated element. Hibernate Validator comes with some built-in constraints, which covers most basic data checks. As we'll see later, you're not limited to them, you can in a minute write your own constraints.

Hibernate Validator comes with a default set of error messages translated in about ten languages if yours is not part of it, please sent us a patch. You can override those messages by creating a ValidatorMessages. You can even add your own additional set of messages while writing your validator annotations. If Hibernate Validator cannot resolve a key from your resourceBundle nor from ValidatorMessage, it falls back to the default built-in values.

Alternatively you can provide a ResourceBundle while checking programmatically the validation rules on a bean or if you want a completly different interpolation mechanism, you can provide an implementation of org.

MessageInterpolator check the JavaDoc for more informations. Extending the set of built-in constraints is extremely easy. Any constraint consists of two pieces: the constraint descriptor the annotation and the constraint validator the implementation class. Here is a simple user-defined descriptor:. This is a user parameter fully dependant on the annotation business. See Error messages. To link a descriptor to its validator implementation, we use the ValidatorClass meta-annotation.

We now have to implement the validator ie. The isValid method should return false if the constraint has been violated. For more examples, refer to the built-in validator implementations. We only have seen property level validation, but you can write a Bean level validation annotation.

You can also build the native executable using. Sometimes, you might need to configure the behavior of the ValidatorFactory , for instance to use a specific ParameterNameProvider. While the ValidatorFactory is instantiated by Quarkus itself, you can very easily tweak it by declaring replacement beans that will be injected in the configuration. If you create a bean of the following types in your application, it will automatically be injected into the ValidatorFactory configuration:.

However, in the case of ConstraintValidator s that are dependent of attributes of the constraint annotation typically when implementing the initialize A constraintAnnotation method , use the Dependent scope to make sure each annotation context has a separate instance of the ConstraintValidator bean. When initializing a constraint validator of a given type, Quarkus will check if a bean of this type is available and, if so, it will use it instead of instantiating one. Thus, as demonstrated in our example, you can fully use injection in your constraint validator beans.

Except in very specific situations, it is recommended to make the said beans ApplicationScoped. You can configure this behavior by adding the following configuration in your application. For example, a Book may need to have a null identifier when passed to the post method because the identifier will be generated , but a non- null identifier when passed to the put method because the method needs the identifier to know what to update. To address this, you can take advantage of validation groups.

Validation groups are markers that you put on your constraints in order to enable or disable them at will. Then add the relevant constraints to Book , assigning the right group to each constraint:. Finally, add a ConvertGroup annotation next to your Valid annotation in your validated method.

Configuration property fixed at build time - All other configuration properties are overridable at runtime. Configuration property.

Enable the fail fast mode. When fail fast is enabled the validation will stop on the first constraint violation detected. Method validation. Define whether overriding methods that override constraints should throw a ConstraintDefinitionException. The default value is false , i. See Section 4. This would pose a strengthening of preconditions to be fulfilled by the caller. Define whether parallel methods that define constraints should throw a ConstraintDefinitionException.

This again is to avoid an unexpected strengthening of preconditions to be fulfilled by the caller. Define whether more than one constraint on a return value may be marked for cascading validation are allowed. Quarkus is open. All dependencies of this project are available under the Apache Software License 2. This website was built with Jekyll , is hosted on Github Pages and is completely open source. Validation with Hibernate Validator.

Prerequisites To complete this guide, you need:. Architecture The application built in this guide is quite simple. Solution We recommend that you follow the instructions in the next sections and create the application step by step. In this tutorial, we show how to validate data with Hibernate validator.

Validating input received from the user to maintain data integrity is an important part of application logic. Validation is incorporated in Java web frameworks such as Stripes, Ninja framework, or Play framework. Bean Validation is a validation model introduced in Java EE 6 platform. The Bean Validation model is supported by constraints in the form of annotations placed on a field, method, or class of a JavaBeans component.

It is also possible to use XML validation descriptors. Hibernate Validator is the reference implementation of Bean Validation. Hibernate Validator allows to express and validate application constraints. The default metadata source are annotations, with the ability to override and extend through the use of XML. It is not tied to a specific application tier or programming model and is available for both server and client application programming.

The Maven pom. The Lombok is used to reduce some boilerplate. The Car bean is decorated with the lombok's Data annotation. It automatically creates the getter and setter methods, equals method, toString method, and hashCode method. The NotNull annotation says that the name property may not be null.