Extend and enhance your Java applications with Domain Specific Languages in Groovy Build your own Domain Specific Languages on top of GroovyIntegrate your existing Java applications using Groovy-based Domain Specific Languages (DSLs)Develop a Groovy scripting interface to TwitterA step-by-step guide to building Groovy-based Domain Specific Languages that run seamlessly in the Java environment In DetailYou may already be aware that the Java virtual machine runs on everything from the largest mainframe to the smallest microchip and supports almost every conceivable application. What you may not realize is that to develop software in some of these scenarios requires a targeted, single purpose language, a Domain Specific Language. The popular scripting language Groovy can be used to create a Domain Specific Language that can run directly on the JVM alongside regular Java code. This comprehensive tutorial will take you through the design and development of Groovy-based Domain Specific Languages. It is a complete guide to the development of several mini-DSLs with a lot of easy-to-understand examples. This book will help you to gain all of the skills needed to develop your own Groovy-based DSLs, as it guides you from the basics through to the more complex meta-programming features of Groovy. The focus is on how the Groovy language can be used to construct domain-specific mini-languages. Practical examples are used throughout to de-mystify the seemingly complex language features and to show how they can be used to create simple and elegant DSLs. The examples include a quick and simple Groovy DSL to interface with Twitter. The book concludes with a chapter focusing on integrating Groovy-based DSLs in such a way that the scripts can be readily incorporated into the readers' own Java applications. The overall goal of this book is to take Java developers through the skills and knowledge they need to start building effective Groovy-based DSLs to integrate into their own applications. This practical guide will teach you how to build Domain Specific Languages in Groovy that integrate seamlessly with your Java applications What you will learn from this book Learn Groovy scripting designed to get Java programmers using Groovy quicklyUse the meta-programming features in Groovy to build your own DSLsLearn everything you need to know about Groovy markup and build your own Groovy builders to simplify your application developmentBuild effective DSLs using operator overloading and Groovy categoriesWork with Groovy closuresGet to grips with the working of Groovy on the JVM and integrate Groovy with your Java applications ApproachThis book is a practical tutorial, walking the reader through examples of building DSLs with Groovy covering meta-programming with Groovy. Some complex concepts are covered in the book but we go through these in a clear and methodically way so that readers will gain a good working knowledge of the techniques involved. Who this book is written forThis book is for Java software developers who have an interest in building domain scripting into their Java applications. No knowledge of Groovy is required, although it will be helpful. The book does not teach Groovy, but quickly introduces the basic ideas of Groovy. An experienced Java developer should have no problems with these and move quickly on to the more involved aspects of creating DSLs with Groovy. No experience of creating a DSL is required. The book should also be useful for experienced Groovy developers who have so far only used Groovy DSLs such as Groovy builders and would like to start building their own Groovy-based DSLs. About the AuthorFergal Dearle is a seasoned software development professional with 23 years of experience in software product development across a wide variety of technologies. He is currently principal consultant with his own software development consulting company, Dearle Technologies Ltd., engaged in design, development, and architecture for new software products for client companies. In the past Fergal has worked in lead architect and developer roles for Candle Corporation on the OMEGAMON product which is now part of IBMs Tivoli product suite as development manager for the Unix implementations of Lotus 1-2-3. In the early 1990s Fergal lead the team at Glockenspiel that developed CommonView, the first object-oriented UI framework for Microsoft Windows. The team was awarded one of the first ever Jolt Productivity Awards by Dr Dobbs Journal. Fergal Dearle PrefaceChapter 1: Introduction to DSL and GroovyChapter 2: Groovy Quick StartChapter 3: Groovy ClosuresChapter 4: Example DSL: GeeTwitterChapter 5: Power Groovy DSL featuresChapter 6: Existing Groovy DSLsChapter 7: Building a BuilderChapter 8: Implementing a Rules DSLChapter 9: Integrating it allIndex