CheckMate

A flexible, fluent validation library for Java

Motivation

A replacement for Apache commons-lang3 Validate, Guava Preconditions, and Spring Assert that uses a fluent API and is more flexible.

Usage

By default most checks will throw an IllegalArgumentException.

CheckMate.check()
    .notEmpty("")
    .validate();

You can also specify what the default exception should be, it must be a RuntimeException, that has a constructor that takes a String.

CheckMate.checkWithDefault(SomeAppSpecificException.class)
    .notEmpty(map)
    .notBlank(str)
    .validate();

An exception can be overridden on a check by check basis.

CheckMate.check()
    .notNull(object).withException(SomeAppSpecificException.class)
    .notEmpty(map).withException(OtherAppException.class)
    .validate();

Overridden exceptions take priority over the default exception.

CheckMate.checkWithDefault(SomeAppSpecificException.class)
    .notEmpty(map)
    .notBlank(str).withException(OtherAppException.class)
    .validate()

The message in the exception can also be changed.

CheckMate.check()
    .notEmpty(map).withMessage("The map should not be empty")
    .notBlank(str)
    .validate();

Sometimes, though, you don't want to throw an exception. So, there are two methods anyInvalid and allInvalid that will let you know if any or all of the checks fail.

boolean anyInvalid = CheckMate.check()
    .notNull(object)
    .notEmpty(someString)
    .anyInvalid();

boolean allInvalid = CheckMate.check()
    .notNull(object)
    .notEmpty(someString)
    .allInvalid();

CheckMate has the ability to validate indexes for Strings, Arrays, and Collections

CheckMate.check()
    .isIndex(3).validIn(Arrays.asList("one", "two", "three", "four", "five", "six"))
    .validate();

You can also check if a number is in a range, by default start inclusive and end exclusive.

CheckMate.check()
    .intValue(7).between(5).and(100)
    .validate();

But there is also a way to specify that the end should be inclusive

CheckMate.check()
    .intValue(100).between(5).and(100).inclusive()
    .validate();

You can also check if an expression is true or false

CheckMate.check()
    .is(value > 0).truthy()
    .is(length == 0).falsy()
    .validate();

"But what if I liked how commons-lang Validate throws NullPointerExceptions when things are null?" Fear not, CheckMate supports that!!

CheckMate.check(CheckMate.Option.THROW_NPE)
    .notEmpty(null)
    .notBlank(str)
    .validate();

This will throw an NPE, instead of an IllegalArgumentException.

Installation

The library is available at Maven Central, simply add this to your pom.xml

<dependency>
    <groupId>xyz.mattyb</groupId>
    <artifactId>checkmate-core</artifactId>
    <version>0.0.5</version>
</dependency>