Book Image

Groovy 2 Cookbook

Book Image

Groovy 2 Cookbook

Overview of this book

Get up to speed with Groovy, a language for the Java Virtual Machine (JVM) that integrates features of both object-oriented and functional programming. This book will show you the powerful features of Groovy 2 applied to real-world scenarios and how the dynamic nature of the language makes it very simple to tackle problems that would otherwise require hours or days of research and implementation. Groovy 2 Cookbook contains a vast number of recipes covering many facets of today's programming landscape. From language-specific topics such as closures and metaprogramming, to more advanced applications of Groovy flexibility such as DSL and testing techniques, this book gives you quick solutions to everyday problems. The recipes in this book start from the basics of installing Groovy and running your first scripts and continue with progressively more advanced examples that will help you to take advantage of the language's amazing features. Packed with hundreds of tried-and-true Groovy recipes, Groovy 2 Cookbook includes code segments covering many specialized APIs to work with files and collections, manipulate XML, work with REST services and JSON, create asynchronous tasks, and more. But Groovy does more than just ease traditional Java development: it brings modern programming features to the Java platform like closures, duck-typing, and metaprogramming. In this new book, you'll find code examples that you can use in your projects right away along with a discussion about how and why the solution works. Focusing on what's useful and tricky, Groovy 2 Cookbook offers a wealth of useful code for all Java and Groovy programmers, not just advanced practitioners.
Table of Contents (17 chapters)
Groovy 2 Cookbook
Credits
About the Authors
About the Reviewers
www.PacktPub.com
Preface
Index

Inheriting constructors in Groovy classes


In Java, class inheritance doesn't support the inheriting of constructors for a number of good reasons (leaving the details of constructing an object to the programmer is generally a good idea). There are times when automatically inheriting the constructors of a class would be really useful and make the code less verbose. One of these cases is when inheriting from a class that extends Exception, where all the constructors are just calling super. Groovy has a convenient annotation for doing just that, @InheritConstructors.

In this recipe, we will explore how to use this annotation.

How to do it...

Let's demonstrate the features that the @InheritConstructors annotation gives:

  1. Create an Exception class: one of the classes that are used to communicate that something is horribly wrong with the code or the data:

    class BusinessException extends Exception {
    
    }
  2. Try to instantiate the class using one of the default constructors of the Exception class, for instance...