README.md

jfluentvalidation

A fluent validation library for Java.

System Requirements

JDK 8 or above.

Examples

private class PersonValidator extends DefaultValidator<Person> {

    PersonValidator() {
        ruleForString(Person::getName).isNotEmpty().startsWith("s").length(0, 4);
        ruleForInteger(Person::getAge).isPositive();
        ruleForBoolean(Person::isMarried).isFalse();
        ruleForZonedDateTime(Person::getSignedIn).isAfter(ZonedDateTime.now().minusDays(1));
        ruleForMap(Person::getPets).isNotEmpty().forEachKey(isLowerCase()).forEachValue(length(0, 5));

        include(new PersonAgeValidator());

        ruleSet("address", () ->  {
            ruleForObject(Person::getAddress).isNotNull();
        });
    }
}

private static class PersonAgeValidator extends DefaultValidator<Person> {

    PersonAgeValidator() {
        ruleForInteger(Person::getAge).must(isOver18());
    }

    private Predicate<Integer> isOver18() {
        return age -> age > 18;
    }
}

Motivation

I'm personally a fan of validation via Hibernate Validator annotations however the number of built in validations is limited and I inevitably have to create custom validators or programmatic Spring validations if I'm working within a project using the Spring Framework. I avoid programmatic in Hibernate Validator at all costs. When it comes to programmatic validations I've always felt these frameworks to be cumbersome and leave a lot to be desired.

Inspiration

This project was inspired by the following open source projects

• https://github.com/JeremySkinner/FluentValidation
• http://joel-costigliola.github.io/assertj/assertj-core.html
• https://github.com/google/truth
• https://github.com/hibernate/hibernate-validator

Run Benchmark

java -jar jfluentvalidation-benchmarks/target/benchmarks.jar