validum

validum is a basic lib that adds validations to your classes that can be called via annotations. It uses Java 8 brand new feature, the annotation target option ElementType.TYPE_USE, that allows you to validate the contents of your arrays and Lists with fine control.

Features

• Full support for both inheritance and composition, how many levels desired;
• Fine control of arrays' components or lists' elements with Java 8's TYPE_USE target option;
• Support for custom validations, just create your own annotation and annotate it with @Validator annotation, and then add a custom Validator for it;
• Class level validations; that is, the annotations can be added to the class declaration, to validate the class's object as a whole;
• Each annotation must specify the types to which it applies, and exceptions are thrown if they are missused.

Planned Features

• Javascript client side validation: you will be able to generate a JSON with validation information from your classes, so that a to-be client side library can validate your forms on the browser as well: client and server validations, unified at least.
• Custom annotation preprocessor for validating each annotation appliable types

Examples

• Simple validations

public class Person {

    private @Required String name;

    private @Natural int age;
}

• Validate arrays and lists, using custom annotation @Super

public class SuperHero {

    private @Required @Array(minLength = 2) List<@Required @Super Power> powers;

    private @CharOnly({'x', 'o'}) char @Array.Fixed(3) [] @Array.Fixed(3) [] currentTickTackToeBoard;
}

Currently Implemented Annotations

Custom annotations can be easily created, but some pre-defined default ones might come in hand. Currently, they are:

• @Required
• @Numeric(min, minCap, max, maxCap, type)
• @Numeric.Max(value)
• @Numeric.Min(value)
• @Numeric.Natural
• @EnumOnly(value)
• @EnumExcept(value)
• @Array(minLength, maxLength)
• @Array.Length(value)