Parameter validation using Hamcrest matchers

Validating input parameters of methods and constructors is a recurring and stupid task, especially when you are writing public APIs. This module tries to ease your life a bit by providing a static validateThat() method, allowing you to throw IllegalArgumentExceptions using hamcrest matchers.

Using the matchers is as easy as

import static info.gehrels.parameterValidation.MatcherValidation.validateThat;
import static org.hamcrest.CoreMatchers.not;
import static org.hamcrest.Matchers.isEmptyOrNullString;

...

public MyConstructor(String name) {
	this.name = validateThat(name, not(isEmptyOrNullString()));
}

or

validateThat("parameter 'name has an invalid value", name, not(isEmptyOrNullString()));

If it fails to validate the parameter, an Exception is thrown:

Exception in thread "main" java.lang.IllegalArgumentException: parameter 'name has an invalid value
Expected: not (null or an empty string)
     but: was null
	at info.gehrels.parameterValidation.MatcherValidation.validateThat(MatcherValidation.java:40)
	...

How to get this?

You will find the lib at Maven Central. Just add the following lines to your pom.xml:

<dependency>
	<groupId>info.gehrels</groupId>
    <artifactId>parameter-validation</artifactId>
	<version>1.1</version>
</dependency>

How is it licensed?

Since the code ist mostly copied from the original Hamcrest sources, i do not claim copyright myself. The code therefore falls under Hamcrests BSD 3-Clause License. It may be found at https://raw.github.com/hamcrest/JavaHamcrest/master/LICENSE.txt