Chapter 12. Bean Validator

Bean Validator Component

Available as of Apache Camel 2.3
The Validator component performs bean validation of the message body using the Java Bean Validation API (JSR 303). Camel uses the reference implementation, which is Hibernate Validator.
Maven users will need to add the following dependency to their pom.xml for this component:
<dependency>
    <groupId>org.apache.camel</groupId>
    <artifactId>camel-bean-validator</artifactId>
    <version>x.x.x</version>
    <!-- use the same version as your Camel core version -->
</dependency>

URI format

bean-validator:label[?options]
or
bean-validator://label[?options]
Where label is an arbitrary text value describing the endpoint. You can append query options to the URI in the following format, ?option=value&option=value&...

URI Options

The following URI options are supported:
Option Default Description
group javax.validation.groups.Default The custom validation group to use.
messageInterpolator org.hibernate.validator.engine. ResourceBundleMessageInterpolator Reference to a custom javax.validation.MessageInterpolator in the Registry.
traversableResolver org.hibernate.validator.engine.resolver. DefaultTraversableResolver Reference to a custom javax.validation.TraversableResolver in the Registry.
constraintValidatorFactory org.hibernate.validator.engine. ConstraintValidatorFactoryImpl Reference to a custom javax.validation.ConstraintValidatorFactory in the Registry.

OSGi deployment

To use Hibernate Validator in the OSGi environment use dedicated ValidationProviderResolver implementation, just as org.apache.camel.component.bean.validator.HibernateValidationProviderResolver. The snippet below demonstrates this approach. Keep in mind that you can use HibernateValidationProviderResolver starting from the Camel 2.13.0.

Example 12.1. Using HibernateValidationProviderResolver

from("direct:test")
  .to("bean-validator://ValidationProviderResolverTest?validationProviderResolver=#myValidationProviderResolver");

...

<bean id="myValidationProviderResolver" class="org.apache.camel.component.bean.validator.HibernateValidationProviderResolver"/>
If no custom ValidationProviderResolver is defined and the validator component has been deployed into the OSGi environment, the HibernateValidationProviderResolver will be automatically used.

Example

Assumed we have a Java bean with the following annotations
Car.java
// Java
public class Car {

    @NotNull
    private String manufacturer;

    @NotNull
    @Size(min = 5, max = 14, groups = OptionalChecks.class)
    private String licensePlate;
    
    // getter and setter
}
and an interface definition for our custom validation group
OptionalChecks.java
public interface OptionalChecks {
}
with the following Apache Camel route, only the @NotNull constraints on the attributes manufacturer and licensePlate will be validated (Apache Camel uses the default group javax.validation.groups.Default).
from("direct:start")
.to("bean-validator://x")
.to("mock:end")
If you want to check the constraints from the group OptionalChecks, you have to define the route like this
from("direct:start")
.to("bean-validator://x?group=OptionalChecks")
.to("mock:end")
If you want to check the constraints from both groups, you have to define a new interface first
AllChecks.java
@GroupSequence({Default.class, OptionalChecks.class})
public interface AllChecks {
}
and then your route definition should looks like this
from("direct:start")
.to("bean-validator://x?group=AllChecks")
.to("mock:end")
And if you have to provide your own message interpolator, traversable resolver and constraint validator factory, you have to write a route like this
<bean id="myMessageInterpolator" class="my.ConstraintValidatorFactory" />
<bean id="myTraversableResolver" class="my.TraversableResolver" />
<bean id="myConstraintValidatorFactory" class="my.ConstraintValidatorFactory" />

from("direct:start")
.to("bean-validator://x?group=AllChecks&messageInterpolator=#myMessageInterpolator&traversableResolver=#myTraversableResolver&constraintValidatorFactory=#myConstraintValidatorFactory")
.to("mock:end")
It's also possible to describe your constraints as XML and not as Java annotations. In this case, you have to provide the file META-INF/validation.xml which could looks like this
validation.xml
<?xml version="1.0" encoding="UTF-8"?>
<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.engine.ResourceBundleMessageInterpolator</message-interpolator>
	<traversable-resolver>org.hibernate.validator.engine.resolver.DefaultTraversableResolver</traversable-resolver>
	<constraint-validator-factory>org.hibernate.validator.engine.ConstraintValidatorFactoryImpl</constraint-validator-factory>
	
	<constraint-mapping>/constraints-car.xml</constraint-mapping>
</validation-config>
and the constraints-car.xml file
constraints-car.xml
<?xml version="1.0" encoding="UTF-8"?>
<constraint-mappings xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://jboss.org/xml/ns/javax/validation/mapping validation-mapping-1.0.xsd"
	xmlns="http://jboss.org/xml/ns/javax/validation/mapping">
	<default-package>org.apache.camel.component.bean.validator</default-package>
	
	<bean class="CarWithoutAnnotations" ignore-annotations="true">
		<field name="manufacturer">
			<constraint annotation="javax.validation.constraints.NotNull" />
		</field>
		
		<field name="licensePlate">
			<constraint annotation="javax.validation.constraints.NotNull" />
			
			<constraint annotation="javax.validation.constraints.Size">
				<groups>
					<value>org.apache.camel.component.bean.validator.OptionalChecks</value>
				</groups>
				<element name="min">5</element>
				<element name="max">14</element>
			</constraint>
		</field>
	</bean>
</constraint-mappings>