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
   

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2. Agenda
   What is Bean Validation?
   What's new in Bean Validation 2.0?
   Questions
   2
   

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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
   

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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
   

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5. Demo
   5
   

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6. Bean Validation 2.0 - JSR 380
   Benefit from new Java 8 language features
   Support for API extensions
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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
   

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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 = ...;
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9. Use Case: Ensure Non-Empty
   Collection Elements
   private List names;
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10. Use Case: Ensure Non-Empty
    Collection Elements
    private List names;
    @NotEmpty
    private List names;
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11. Use Case: Ensure Non-Empty
    Collection Elements
    private List names;
    @OnElements(constraint=@NotEmpty)
    private List names;
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12. Use Case: Ensure Non-Empty
    Collection Elements
    private List names;
    private List<@NotEmpty String> names;
    @OnElements(constraint=@NotEmpty)
    private List names;
    12
    

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13. Use Case: Ensure Non-Empty
    Collection Elements
    private List names;
    private List<@NotEmpty
    @Pattern(regexp="[a-zA-Z]*") String> names;
    @OnElements(constraint=@NotEmpty)
    private List names;
    13
    

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14. private List<@NotEmpty
    @Pattern(regexp="[a-zA-Z]*") String> names;
    Use Case: Ensure Non-Empty
    Collection Elements
    private List names;
    @NotEmpty
    private List<@NotEmpty String> names;
    @OnElements(constraint=@NotEmpty)
    private List names;
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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
    

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16. Cascaded Validation
    @Valid
    private List addresses;
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17. Cascaded Validation
    @Valid
    private List addresses;
    private List<@Valid Address> addresses;
    17
    

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18. Cascaded Validation
    @Valid
    private List addresses;
    private List<@Valid Address> addresses;
    private Map<@Valid Comment, Integer> scorePerComment;
    18
    

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19. Cascaded Validation
    @Valid
    private List addresses;
    private List<@Valid Address> addresses;
    private Map<@Valid Comment, Integer> scorePerComment;
    private Map<@Valid AddressType,
    List<@Valid Address>> addressesByType;
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20. Further Supported Containers
    Optional, OptionalInt, OptionalLong, OptionalDouble
    JavaFX's property types
    Optional<@Email String> getEmail() { ... };
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21. Custom Containers
    Specific collection types (e.g. Google Guava)
    Other JVM languages (Ceylon, Scala etc.)
    Enabled via Extractor SPI
    private Table revenuePerYearAndCategory;
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22. private Table revenuePerYearAndCategory;
    private Table
    revenuePerYearAndCategory;
    Custom Containers
    Specific collection types (e.g. Google Guava)
    Other JVM languages (Ceylon, Scala etc.)
    Enabled via Extractor SPI
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23. Demo
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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
    );
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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
    );
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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();
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27. New Constraints
    @NotEmpty, @NotBlank
    @Email
    @Positive, @PositiveOrZero , @Negative, @NegativeOrZero
    @PastOrPresent, @FutureOrPresent
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28. Other Java 8 Goodies
    Real parameter names in error messages
    ConstraintValidator without initialize()
    public class NotNullValidator implements
    ConstraintValidator {
    public void initialize(NotNull constraintAnnotation) {}
    public boolean isValid(Object object,
    ConstraintValidatorContext ctx) {
    return object != null;
    }
    }
    public class NotNullValidator implements
    ConstraintValidator {
    public boolean isValid(Object object,
    ConstraintValidatorContext ctx) {
    return object != null;
    }
    }
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29. Status
    Released final
    version in August
    Reference implementation:
    Hibernate Validator 6.0
    29
    

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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
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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
    

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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
    

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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
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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/
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