EclipseLink/Development/JPA 2.0/validation api integration

JPA 2.0: Validation API Integration

JPA 2.0 Root | bug 266927

Issue Summary

JPA 2.0 spec mandates that a persistence provider needs to validate managed classes (entities, mapped superclasses, and embeddable classes) using Bean Validation API(JSR-303) on lifecycle events. Please see JPA spec section 3.6 for more details.

General Solution

Goals

• EclipseLink should not require either Bean Validation API or a Bean Validation Provider at run time if Bean Validation is not enabled.
• There should be no performance overhead at runtime if Bean Validation is disabled
• There should be no dependency from foundation to jpa module
• Ensure EclipseLink JPA users who do not wish to use Validation do not require the javax.validation library on their classpath

Bootstrapping of ValidatorFactory and other Validation metadata

Validation Mode: Specified by user as value of property "javax.persistence.validation.mode" or as "validation-mode" element in persistence.xml.
Validation Groups: Specified by user as value of property "javax.persistence.validation.group.pre-*". It is specified as comma separated fully qualified class names of the groups.
ValidatorFactory: An instance of the factory would be used to obtain Validator used to perform validation. ValidatorFactory is obtained in one of following ways as specified by JPA spec:

• Passed as value of property "javax.persistence.validation.factory" while creating EMF using Persistence.createEMF() or from a JavaEE container
• While running in JavaSE mode, created by EclipseLink using Validation.buildDefaultValidatorFactory()

Enabling Automatic Bean Validation on lifecycle events

• Introduce a DescriptorEventListener listener called BeanValidationListener.
  • BeanValidationListener would be initialized with ValidatorFactory, Validation Mode, Validation Group and a pointer to the MetaDataProject
• Install this listener at deployment time if Bean Validation is enabled
• BeanValidationListener performs Bean Validation on life cycle events prePersit, preUpdate and preRemove

Disabling cascading of validation and loading of lazy attributes

Spec requires that while executing automatic validation, Validation cascade (@Valid) must not occur for entity associations (single- or multi-valued). Validation should also not trigger loading of a lazy attribute.

• When obtaining a Validator instance to perform validation, supply a TraversableResolver that
  • returns false for isReachable() call corresponding to any lazy atttibutes
  • returns false for isCascadable() call corresponding to any relationships

Future Considerations

• Bean Validation Meta Data constraints like @Size can be used at DDL generation time.