Vavr-Beanvalidation 2.0

This module provides support for bean validation 2.0 (JSR380). Can be used with any service provider of the bean validation spec e.g. org.hibernate.validator:hibernate-validator

Features:

• @Size for vavr's Traversable<T>
• @NotEmpty for vavr's Value<T>
• All available validations can be applied to nested Tuple Values. See example below
• All available validations can be applied to vavr's Map<K, V>s and Traversable<T>s including Multimap<K, V>s
• All available validations on nested collection element types now give proper feedback as to where violations occurred (index for Seqs and key for Maps)

Using the module

Add the dependency to your classpath. For maven:

<dependency>
    <groupId>io.vavr</groupId>
    <artifactId>vavr-beanvalidation2</artifactId>
    <version>0.10.0</version>
</dependency>

For the bean validation service provider to pick it up the constraints must be registered. Add the following to your validation.xml:

...
<constraint-mapping>META-INF/constraints-vavr.xml</constraint-mapping>
...

Or register via java config of your validation provider. See javax.validation.Configuration#addMapping.

Since it would be very tedious to register all the ValueExtractors for the tuple elements by yourself, configuration is automatically done for you via Java service loader. The definition in META-INF/services is picked up by the validation service provider.

Now JSR 380 validations will work on vavr types. e.g.

public class TestBean {

    @Size(min = 1, max = 2)
    private Seq<@Max(10) Integer> seqWithOneOrTwoDecimals = List.of(0);

    @NotEmpty
    private Either<String, @Positive Integer> mustNotBeLeftOrNull = Either.right(42);
    
    private Tuple3<@NotBlank String, @NotBlank String, @NotNull Integer> allElementsMustBeProvided =
        Tuple.of("a", "x", 3);

    @NotNull
    @NotEmpty
    private Map<@Pattern(regexp = "^[a-z]$") String, @NotBlank String> allCharKeysMustHaveNonBlankValues =
        HashMap.of("a", "Alice");
    
    // getters and setters
    
}

Considerations/Limitations

• While it is possible to validate Try<T> and Lazy<T>, the usage of these monads for beanvalidation is questionable. Furthermore if the nested value of Lazy<T> is to be validated, evaluation will be forced and thus defeating the purpose of Lazy<T>.
• Validation of io.vavr.control.Validation<T> is out of scope/undefined for obvious reasons.