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Jakarta Validation

Java Bean Validation is widely recognized as the standard for integrating validation logic into Java applications. It utilizes a uniform approach to validation by allowing developers to annotate domain model properties with declarative validation constraints. These constraints are enforced at runtime, with options for both built-in and custom-defined rules.

webforJ seamlessly integrates with Bean Validation through the JakartaValidator adapter, providing robust support out of the box.

Installation​

It's necessary to include a compatible implementation, such as Hibernate Validator, in your classpath. If your environment doesn't come with this implementation by default, you can add it manually by using the following Maven dependencies:

<dependency>
    <groupId>org.hibernate.validator</groupId>
    <artifactId>hibernate-validator</artifactId>
    <version>8.0.1.Final</version>
</dependency>
<dependency>
    <groupId>org.glassfish.expressly</groupId>
    <artifactId>expressly</artifactId>
    <version>5.0.0</version>
</dependency>

The JakartaValidator​

The JakartaValidator class serves as an adapter, bridging the webforJ binding context with Jakarta Validation. This integration enables the use of complex validation rules directly via annotations in the bean class.

Activating JakartaValidator​

To activate the JakartaValidator across the entire context, you typically use the useJakartaValidator parameter when constructing the BindingContext.

BindingContext<User> context = new BindingContext<>(User.class, true);

Defining constraints for bean properties​

Annotation-based constraints are directly applied within the bean class to specify validation conditions, as illustrated in the example below:

public class Hero {
  @NotEmpty(message = "Name cannot be empty")
  @Length(min = 3, max = 20)
  private String name;

  @NotEmpty(message = "Unspecified power")
  @Pattern(regexp = "Fly|Invisible|LaserVision|Speed|Teleportation", message = "Invalid power")
  private String power;

  // getters and setters
}

Such constraints are as effective as those set programmatically during the binding initialization, ensuring consistent validation outcomes.

warning

Currently, the JakartaValidator only recognizes constraints that are directly assigned to properties and ignores any validations not directly associated with properties.