Keeping Your Data Sane with Bean Validation 2.0

-- Presented at JavaOne 2017 --

Rich UIs, schemaless data stores, REST-based APIs—the need for powerful data validation is greater than ever. The Bean Validation standard is here to help, defining a rich validation API based on annotations.

Bean Validation 2.0 (JSR 380) makes validation even more expressive, leveraging Java 8 features such as type and repeatable annotations or default methods. This opens up exciting opportunities for Bean Validation, such as List<@Email String>. Part of Java EE 8, Bean Validation 2.0 can be used on Java SE too.

This code-centric session explores many of the new features right in the IDE. Find out how Bean Validation integrates with specs such as JAX-RS and how to implement your own constraints, ensuring that your data is sane at all times.

Transcript

1. Keeping Your Data Sane with Bean Validation 2.0 Gunnar Morling @gunnarmorling 1
2. Agenda What is Bean Validation? What's new in Bean Validation 2.0? Questions 2
3. Gunnar Morling Open source software engineer at Red Hat Debezium Hibernate Spec Lead for Bean Validation 2.0 Other projects: ModiTect, MapStruct gunnar@hibernate.org @gunnarmorling http://in.relation.to/gunnar-morling/ 3
4. What is Bean Validation? "Constrain once, validate everywhere" Constraints for JavaBeans Validation via API or automatically ​ JPA JSF, Spring MVC, GWT JAX-RS Extensible (custom constraints) BV 1.1: ​ method validation 4
5. Demo 5
6. Bean Validation 2.0 - JSR 380 Benefit from new Java 8 language features Support for API extensions 6
7. Use Case: Different Passwords for Different Roles @Size.List({ @Size(min = 8, group = Default.class), @Size(min = 12, group = Admin.class) }) private char[] password = ...; 7
8. Use Case: Different Passwords for Different Roles @Size.List({ @Size(min = 8, group = Default.class), @Size(min = 12, group = Admin.class) }) private char[] password = ...; @Size(min = 8, group = Default.class) @Size(min = 12, group = Admin.class) private char[] password = ...; 8
9. Use Case: Ensure Non-Empty Collection Elements private List<String> names; 9
10. Use Case: Ensure Non-Empty Collection Elements private List<String> names; @NotEmpty private List<String> names; 10
11. Use Case: Ensure Non-Empty Collection Elements private List<String> names; @OnElements(constraint=@NotEmpty) private List<String> names; 11
12. Use Case: Ensure Non-Empty Collection Elements private List<String> names; private List<@NotEmpty String> names; @OnElements(constraint=@NotEmpty) private List<String> names; 12
13. Use Case: Ensure Non-Empty Collection Elements private List<String> names; private List<@NotEmpty @Pattern(regexp="[a-zA-Z]*") String> names; @OnElements(constraint=@NotEmpty) private List<String> names; 13
14. private List<@NotEmpty @Pattern(regexp="[a-zA-Z]*") String> names; Use Case: Ensure Non-Empty Collection Elements private List<String> names; @NotEmpty private List<@NotEmpty String> names; @OnElements(constraint=@NotEmpty) private List<String> names; 14
15. @Target({ METHOD, FIELD, ANNOTATION_TYPE, CONSTRUCTOR, PARAMETER, TYPE_USE }) @Retention(RUNTIME) @Repeatable(List.class) @Documented @Constraint(validatedBy = { }) public @interface Size { ... } Type Annotations (JSR 308) New element type TYPE_USE 15
16. Cascaded Validation @Valid private List<Address> addresses; 16
17. Cascaded Validation @Valid private List<Address> addresses; private List<@Valid Address> addresses; 17
18. Cascaded Validation @Valid private List<Address> addresses; private List<@Valid Address> addresses; private Map<@Valid Comment, Integer> scorePerComment; 18
19. Cascaded Validation @Valid private List<Address> addresses; private List<@Valid Address> addresses; private Map<@Valid Comment, Integer> scorePerComment; private Map<@Valid AddressType, List<@Valid Address>> addressesByType; 19
20. Further Supported Containers Optional, OptionalInt, OptionalLong, OptionalDouble JavaFX's property types Optional<@Email String> getEmail() { ... }; 20
21. Custom Containers Specific collection types (e.g. Google Guava) Other JVM languages (Ceylon, Scala etc.) Enabled via Extractor SPI private Table<Year, String, Integer> revenuePerYearAndCategory; 21
22. private Table<Year, String, Integer> revenuePerYearAndCategory; private Table<Year, String, @Positive Integer> revenuePerYearAndCategory; Custom Containers Specific collection types (e.g. Google Guava) Other JVM languages (Ceylon, Scala etc.) Enabled via Extractor SPI 22
23. Demo 23
24. Use Case: Delivery Date in the Future @Past/@Future supported for JSR 310 types: java.time.LocalDateTime, ZonedDateTime etc. @Future private LocalDate deliveryDate = LocalDate.of( 2017, Month.MAY, 12 ); 24
25. Use Case: Delivery Date in the Future @Past/@Future supported for JSR 310 types: java.time.LocalDateTime, ZonedDateTime etc. @FutureOrPresent private LocalDate deliveryDate = LocalDate.of( 2017, Month.MAY, 12 ); @Future private LocalDate deliveryDate = LocalDate.of( 2017, Month.MAY, 12 ); 25
26. Use Case: Testing ValidatorFactory vf = Validation.byDefaultProvider() .configure() .clockProvider( new FixedClockProvider( ZonedDateTime.of( 2016, 6, 15, 0, 0, 0, 0, ZoneId.of( "Europe/Paris" ) ) ) ) .buildValidatorFactory(); 26
27. New Constraints @NotEmpty, @NotBlank @Email @Positive, @PositiveOrZero , @Negative, @NegativeOrZero @PastOrPresent, @FutureOrPresent 27
28. Other Java 8 Goodies Real parameter names in error messages ConstraintValidator without initialize() public class NotNullValidator implements ConstraintValidator<NotNull, Object> { public void initialize(NotNull constraintAnnotation) {} public boolean isValid(Object object, ConstraintValidatorContext ctx) { return object != null; } } public class NotNullValidator implements ConstraintValidator<NotNull, Object> { public boolean isValid(Object object, ConstraintValidatorContext ctx) { return object != null; } } 28
29. Status Released final version in August Reference implementation: Hibernate Validator 6.0 29
30. Final Release Part of Java EE 8 Contained in GlassFish 5; easy-to-use patch for WildFly Supported by Spring 5 Everything open source: spec, API, TCK and reference implementation 30
31. Summary Support for container-element constraints Repeatable constraints New constraint types Improved date/time support ConstraintValidator#initialize() is a default method http://beanvalidation.org/2.0/spec/#whatsnew-20 31.1
32. Outlook Bean Validation 2.1 Constraint-API ConstraintMapping mapping = ...; mapping.type( Marathon.class ) .property( "numberOfHelpers", FIELD ) .constraint( new MinDef().value( 1 ) ) .property( "runners", METHOD ) .valid(); 31.2
33. Outlook Bean Validation 2.1 Constraint-API ConstraintMapping mapping = ...; mapping.type( Marathon.class ) .property( "numberOfHelpers", FIELD ) .constraint( new MinDef().value( 1 ) ) .property( "runners", METHOD ) .valid(); mapping.constraintDefinition( FileExists.class ) .validateType( File.class ) .with( f -> f.exists() ); Constraint-API: Lambda 31.3
34. Resources Spec Reference implementation API, specifikation, TCK, website Contributions welcome! @gunnarmorling http://beanvalidation.org/2.0/spec/ github.com/hibernate/hibernate-validator/ github.com/beanvalidation/ 32