tiny-preconditions

A really-really small library to check method arguments.

How to use

Just add this dependency to you maven project :

<dependency>
    <groupId>fr.fxjavadevblog</groupId>
    <artifactId>tiny-preconditions</artifactId>
    <version>1.0.10</version>
</dependency>

Usage

The class Checker offers static methods to check various conditions :

• Checker.notNull : checks nullity
• Checker.respect : checks a fields against
  • a REGEXP if a pattern is given
  • a Predicate which takes the parameter and returns true or false
• Checker.inRange : checks if an integer is between 2 integers (included)
• Checker.notEmpty : checks if a collection is empty

Here is an example used in the JUnit tests :

public static void demoPreconditions(String name, Integer age, byte[] picture, Collection<String> skills)
{
    Checker.notNull("name",name);
    Checker.notNull("name",name, Predicate.not(String::isEmpty); // Java 11
    Checker.notNull("age", age, IllegalArgumentException::new);
    Checker.notNull(picture, "picture");
    Checker.inRange("age", age, 14, 18);
    Checker.inRange("age", age, 14, 18, AgeBusinessException::new);
    Checker.respects("name", name, "[A-Z]+");
    Checker.respects("picture", picture, ValidationUtils::isPngData);
    Checker.notEmpty("skills", skills);
}

i18n

Messages are bundled into the file "tiny-preconditions.properties". They are loaded and accessed by the enum class PreconditionMessage.

Here are the default messages :

SHOULD_NOT_BE_NULL=The argument {0} should not be null
SHOULD_NOT_BE_EMPTY=The argument {0} should not be empty
SHOULD_BE_BETWEEN=The argument {0} should be between {1} and {2} inclusive
SHOULD_MATCH_REGEXP=The argument {0} should match this regexp {1}
SHOULD_RESPECT_BOOLEAN_CONDITION=The argument {0} should respect this boolean condition \: {1}
MAP_SHOULD_NOT_CONTAIN_ANY_NULL_REFERENCE=The map {0} should not contain any null references but key [{1}] refers to null

Localized and custom messages can be easily added.

Code quality

This project aims to be rated A with Codacy and Codefactor.

Developments are and will be made in that goal.

Current quality status :

Travis CI Building

This project is build with Travis-CI and tested with JDK 8 and JDK 11.

Current build status :

I Need You!

Please feel free to collaborate to this tiny project to make it as tiny as possible but as powerfull as it could be.

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