Chapter 14. Bean Validation

14.1. About Bean Validation
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Bean Validation, or JavaBeans Validation, is a model for validating data in Java objects. The model uses built-in and custom annotation constraints to ensure the integrity of application data. The specification is documented here: JSR 349: Bean Validation 1.1.

Hibernate Validator is the JBoss EAP implementation of Bean Validation. It is also the reference implementation of the JSR.

JBoss EAP is 100% compliant with JSR 349 Bean Validation 1.1 specification. Hibernate Validator also provides additional features to the specification.

To get started with Bean Validation, see the bean-validation quickstart that ships with JBoss EAP. For information about how to download and run the quickstarts, see Using the Quickstart Examples.

14.2. Validation Constraints
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14.2.1. About Validation Constraints
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Validation constraints are rules applied to a Java element, such as a field, property or bean. A constraint will usually have a set of attributes used to set its limits. There are predefined constraints, and custom ones can be created. Each constraint is expressed in the form of an annotation.

The built-in validation constraints for Hibernate Validator are listed here: Hibernate Validator Constraints.

14.2.2. Hibernate Validator Constraints
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Note

When applicable, the application-level constraints lead to creation of database-level constraints that are described in the Hibernate Metadata Impact column in the table below.

Java-specific Validation Constraints

The following table includes validation constraints defined in the Java specifications, which are included in the javax.validation.constraints package.

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Annotation	Property type	Runtime checking	Hibernate Metadata impact
`@AssertFalse`	Boolean	Check that the method evaluates to false. Useful for constraints expressed in code rather than annotations.	None.
`@AssertTrue`	Boolean	Check that the method evaluates to true. Useful for constraints expressed in code rather than annotations.	None.
`@Digits(integerDigits=1)`	Numeric or string representation of a numeric	Check whether the property is a number having up to `integerDigits` integer digits and `fractionalDigits` fractional digits.	Define column precision and scale.
`@Future`	Date or calendar	Check if the date is in the future.	None.
`@Max(value=)`	Numeric or string representation of a numeric	Check if the value is less than or equal to max.	Add a check constraint on the column.
`@Min(value=)`	Numeric or string representation of a numeric	Check if the value is more than or equal to Min.	Add a check constraint on the column.
`@NotNull`		Check if the value is not null.	Column(s) are not null.
`@Past`	Date or calendar	Check if the date is in the past.	Add a check constraint on the column.
`@Pattern(regexp="regexp", flag=)` or `@Patterns( {@Pattern(…)} )`	String	Check if the property matches the regular expression given a match flag. See `java.util.regex.Pattern`.	None.
`@Size(min=, max=)`	Array, collection, map	Check if the element size is between min and max, both values included.	None.
`@Valid`	Object	Perform validation recursively on the associated object. If the object is a Collection or an array, the elements are validated recursively. If the object is a Map, the value elements are validated recursively.	None.

Note

The parameter @Valid is a part of the Bean Validation specification, even though it is located in the javax.validation.constraints package.

Hibernate Validator-specific Validation Constraints

The following table includes vendor-specific validation constraints, which are a part of the org.hibernate.validator.constraints package.

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Annotation	Property type	Runtime checking	Hibernate Metadata impact
`@Length(min=, max=)`	String	Check if the string length matches the range.	Column length will be set to max.
`@CreditCardNumber`	String	Check whether the string is a well formatted credit card number, derivative of the Luhn algorithm.	None.
`@EAN`	String	Check whether the string is a properly formatted EAN or UPC-A code.	None.
`@Email`	String	Check whether the string is conform to the e-mail address specification.	None.
`@NotEmpty`		Check if the string is not null nor empty. Check if the connection is not null nor empty.	Columns are not null for String.
`@Range(min=, max=)`	Numeric or string representation of a numeric	Check if the value is between min and max, both values included.	Add a check constraint on the column.

14.2.3. Bean Validation Using Custom Constraints
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Bean Validation API defines a set of standard constraint annotations, such as @NotNull, @Size, and so on. However, in cases where these predefined constraints are not sufficient, you can easily create custom constraints tailored to your specific validation requirements.

Creating a Bean Validation custom constraint requires that you create a constraint annotation and implement a constraint validator. The following abbreviated code examples are taken from the bean-validation-custom-constraint quickstart that ships with JBoss EAP. See that quickstart for a complete working example.

14.2.3.1. Creating A Constraint Annotation
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The following example shows the personAddress field of entity Person is validated using a set of custom constraints defined in the class AddressValidator.

Create the entity Person

Example: Person Class

package org.jboss.as.quickstarts.bean_validation_custom_constraint;

@Entity
@Table(name = "person")
public class Person implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue
    @Column(name = "person_id")
    private Long personId;

    @NotNull

    @Size(min = 4)
    private String firstName;

    @NotNull
    @Size(min = 4)
    private String lastName;

    // Custom Constraint @Address for bean validation
    @NotNull
    @Address
    @OneToOne(mappedBy = "person", cascade = CascadeType.ALL)
    private PersonAddress personAddress;

    public Person() {

    }

    public Person(String firstName, String lastName, PersonAddress address) {
        this.firstName = firstName;
        this.lastName = lastName;
        this.personAddress = address;
    }

    /* getters and setters omitted for brevity*/
}

Create the constraint validator files:

Example: Address Interface

package org.jboss.as.quickstarts.bean_validation_custom_constraint;

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

// Linking the AddressValidator class with @Address annotation.
@Constraint(validatedBy = { AddressValidator.class })
// This constraint annotation can be used only on fields and method parameters.
@Target({ ElementType.FIELD, ElementType.PARAMETER })
@Retention(value = RetentionPolicy.RUNTIME)
@Documented
public @interface Address {

    // The message to return when the instance of MyAddress fails the validation.
    String message() default "Address Fields must not be null/empty and obey character limit constraints";

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

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

Example: PersonAddress Class

package org.jboss.as.quickstarts.bean_validation_custom_constraint;

import java.io.Serializable;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.OneToOne;
import javax.persistence.PrimaryKeyJoinColumn;
import javax.persistence.Table;

@Entity
@Table(name = "person_address")
public class PersonAddress implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    @Column(name = "person_id", unique = true, nullable = false)
    @GeneratedValue(strategy = GenerationType.SEQUENCE)
    private Long personId;

    private String streetAddress;
    private String locality;
    private String city;
    private String state;
    private String country;
    private String pinCode;

    @OneToOne
    @PrimaryKeyJoinColumn
    private Person person;

    public PersonAddress() {

    }

    public PersonAddress(String streetAddress, String locality, String city, String state, String country, String pinCode) {
        this.streetAddress = streetAddress;
        this.locality = locality;
        this.city = city;
        this.state = state;
        this.country = country;
        this.pinCode = pinCode;
    }

    /* getters and setters omitted for brevity*/
}

14.2.3.2. Implementing A Constraint Validator
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Having defined the annotation, you need to create a constraint validator that is able to validate elements with an @Address annotation. To do so, implement the interface ConstraintValidator as shown below:

Example: AddressValidator Class

package org.jboss.as.quickstarts.bean_validation_custom_constraint;

import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;
import org.jboss.as.quickstarts.bean_validation_custom_constraint.PersonAddress;

public class AddressValidator implements ConstraintValidator<Address, PersonAddress> {

    public void initialize(Address constraintAnnotation) {
    }

    /**
     * 1. A null address is handled by the @NotNull constraint on the @Address.
     * 2. The address should have all the data values specified.
     * 3. Pin code in the address should be of at least 6 characters.
     * 4. The country in the address should be of at least 4 characters.
     */
    public boolean isValid(PersonAddress value, ConstraintValidatorContext context) {
        if (value == null) {
            return true;
        }

        if (value.getCity() == null || value.getCountry() == null || value.getLocality() == null
            || value.getPinCode() == null || value.getState() == null || value.getStreetAddress() == null) {
            return false;
        }

        if (value.getCity().isEmpty()
            || value.getCountry().isEmpty() || value.getLocality().isEmpty()
            || value.getPinCode().isEmpty() || value.getState().isEmpty() || value.getStreetAddress().isEmpty()) {
            return false;
        }

        if (value.getPinCode().length() < 6) {
            return false;
        }

        if (value.getCountry().length() < 4) {
            return false;
        }

        return true;
    }
}

14.3. Validation Configuration
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You can configure bean validation using XML descriptors in the validation.xml file located in the /META-INF directory. If this file exists in the class path, its configuration is applied when the ValidatorFactory gets created.

Example: Validation Configuration File

The following example shows several configuration options of the validation.xml file. All the settings are optional. These options can also be configured using the javax.validation package.

<validation-config xmlns="http://jboss.org/xml/ns/javax/validation/configuration"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://jboss.org/xml/ns/javax/validation/configuration">

    <default-provider>
        org.hibernate.validator.HibernateValidator
    </default-provider>
    <message-interpolator>
        org.hibernate.validator.messageinterpolation.ResourceBundleMessageInterpolator
    </message-interpolator>
    <constraint-validator-factory>
        org.hibernate.validator.engine.ConstraintValidatorFactoryImpl
    </constraint-validator-factory>

    <constraint-mapping>
        /constraints-example.xml
    </constraint-mapping>

    <property name="prop1">value1</property>
    <property name="prop2">value2</property>
</validation-config>

The node default-provider allows to choose the bean validation provider. This is useful if there is more than one provider on the classpath. The message-interpolator and constraint-validator-factory properties are used to customize the used implementations for the interfaces MessageInterpolator and ConstraintValidatorFactory, which are defined in the javax.validation package. The constraint-mapping element lists additional XML files containing the actual constraint configuration.

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14.1. About Bean Validation
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14.2. Validation Constraints
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14.2.1. About Validation Constraints
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14.2.2. Hibernate Validator Constraints
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14.2.3. Bean Validation Using Custom Constraints
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14.2.3.1. Creating A Constraint Annotation
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14.2.3.2. Implementing A Constraint Validator
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14.3. Validation Configuration
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Chapter 14. Bean Validation

14.1. About Bean ValidationCopier lienLien copié sur presse-papiers!

14.2. Validation ConstraintsCopier lienLien copié sur presse-papiers!

14.2.1. About Validation ConstraintsCopier lienLien copié sur presse-papiers!

14.2.2. Hibernate Validator ConstraintsCopier lienLien copié sur presse-papiers!

14.2.3. Bean Validation Using Custom ConstraintsCopier lienLien copié sur presse-papiers!

14.2.3.1. Creating A Constraint AnnotationCopier lienLien copié sur presse-papiers!

14.2.3.2. Implementing A Constraint ValidatorCopier lienLien copié sur presse-papiers!

14.3. Validation ConfigurationCopier lienLien copié sur presse-papiers!

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14.1. About Bean Validation
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14.2. Validation Constraints
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14.2.1. About Validation Constraints
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14.2.2. Hibernate Validator Constraints
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14.2.3. Bean Validation Using Custom Constraints
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14.2.3.1. Creating A Constraint Annotation
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14.2.3.2. Implementing A Constraint Validator
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14.3. Validation Configuration
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