Learning Groovy

116 Pages·2016·11.79 MB·English

by  Adam L. Davis (auth.)

Learning
Groovy
—
Adam L. Davis
Learning Groovy

Adam L. Davis
Learning Groovy
Adam L. Davis
New York, USA
ISBN-13 (pbk): 978-1-4842-2116-7 ISBN-13 (electronic): 978-1-4842-2117-4
DOI 10.1007/978-1-4842-2117-4
Library of Congress Control Number: 2016949453
Copyright © 2016 by Adam L. Davis
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Lead Editor: Steve Anglin
Technical Reviewer: Manuel Jordan Elera
Editorial Board: Steve Anglin, Pramila Balan, Laura Berendson, Aaron Black,
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Printed on acid-free paper
To my parents, to whom I owe everything in ways large and small.
To my children, who mean the world to me.
To my wife, for putting up with me and supporting me.

Contents at a Glance
About the Author .............................................................................xv
About the Technical Reviewer .......................................................xvii
Acknowledgments ..........................................................................xix
About This Book..............................................................................xxi
■ Part I: Getting Groovy ..................................................... 1
■ Chapter 1: Software to Install .........................................................3
■ Chapter 2: Groovy 101 ....................................................................5
■ Chapter 3: Tools ............................................................................15
■ Chapter 4: GDK .............................................................................17
■ Chapter 5: Coming from Java .......................................................23
■ Part II: Advanced Groovy .............................................. 29
■ Chapter 6: Groovy Design Patterns ...............................................31
■ Chapter 7: DSLs ............................................................................35
■ Chapter 8: Traits ...........................................................................41
■ Chapter 9: Functional Programming ............................................45
■ Chapter 10: Groovy GPars .............................................................55
■ Part III: The Groovy Ecosystem ..................................... 59
■ Chapter 11: Groovy Awesomeness ...............................................61
■ Chapter 12: Gradle ........................................................................65
v
■ CONTENTS AT A GLANCE
■ Chapter 13: Grails .........................................................................71
■ Chapter 14: Spock ........................................................................79
■ Chapter 15: Ratpack .....................................................................83
■ Appendix A: Java/Groovy ..............................................................95
■ Appendix B: Resources .................................................................97
Index ................................................................................................99
vi
Contents
About the Author .............................................................................xv
About the Technical Reviewer .......................................................xvii
Acknowledgments ..........................................................................xix
About This Book..............................................................................xxi
■ Part I: Getting Groovy ..................................................... 1
■ Chapter 1: Software to Install .........................................................3
Java/Groovy .............................................................................................3
Trying It Out ..............................................................................................................4
Others ......................................................................................................4
Code on Github ........................................................................................4
■ Chapter 2: Groovy 101 ....................................................................5
What Is Groovy? ......................................................................................5
Compact Syntax ......................................................................................6
Dynamic def ............................................................................................6
List and Map Defi nitions ..........................................................................6
Groovy GDK ..............................................................................................7
Everything Is an Object ...........................................................................7
Easy Properties .......................................................................................7
GString ....................................................................................................8
Closures ..................................................................................................8
vii
■ CONTENTS
A Better Switch .......................................................................................9
Meta-Programming ...............................................................................10
Static Type-Checking .............................................................................10
Elvis Operator ........................................................................................11
Safe Dereference Operator ....................................................................12
A Brief History .......................................................................................12
Groovy 1.8 ...............................................................................................................12
Groovy 2.0 ...............................................................................................................13
Groovy 2.1 ...............................................................................................................13
Groovy 2.2 ...............................................................................................................13
Groovy 2.3 ...............................................................................................................14
Groovy 2.4 ...............................................................................................................14
Summary ...............................................................................................14
■ Chapter 3: Tools ............................................................................15
Console ..................................................................................................15
Compilation ...........................................................................................15
Shell ......................................................................................................16
Documentation ......................................................................................16
■ Chapter 4: GDK .............................................................................17
Collections .............................................................................................17
Spread ....................................................................................................................18
GPath ......................................................................................................................18
IO ...........................................................................................................18
Files ........................................................................................................................18
URLs .......................................................................................................................19
Ranges ..................................................................................................20
viii
■ CONTENTS
Utilities ..................................................................................................21
Confi gSlurper ..........................................................................................................21
Expando ..................................................................................................................21
ObservableList/Map/Set .........................................................................................22
■ Chapter 5: Coming from Java .......................................................23
Default Method Values ..........................................................................23
Equals, Hashcode, and More .................................................................23
Regex Pattern Matching ........................................................................24
Missing Java Syntax ..............................................................................25
Semicolon Optional ...............................................................................25
Where Are Generics? .............................................................................26
Groovy Numbers ....................................................................................26
Boolean-Resolution ...............................................................................26
Map Syntax ...........................................................................................27
Summary ...............................................................................................27
■ Part II: Advanced Groovy .............................................. 29
■ Chapter 6: Groovy Design Patterns ...............................................31
Strategy Pattern ....................................................................................31
Meta-Programming ...............................................................................32
Meta-Class .............................................................................................................32
Categories ..............................................................................................................32
Missing Methods ...................................................................................33
Delegation .............................................................................................34
ix