What is Groovy. Why Groovy is an agile dynamic language? What makes Groovy special? Groovy tool set. Getting started from suggestions.

1. Groovy
and
Noteworthy
Izzet Mustafayev@EPAM Systems
@webdizz
http://webdizz.name

2. Agenda
● Groovy
○ Specials
○ Basics
○ Infrastructure
● Demo
● Getting Started

3. Groovy
Specials

4. Groovy is an agile dynamic language

5. ​println 'Hello World​​​​​​​!'​​

6. Java is a Groovy but Groovy is not Java

7. Groovy supports DSL

8. Groovy supports DSL
● A flexible syntax
● Closures
● Meta-programming
● Operator overloading
● No dots and commas

9. Groovy provides statically type check

10. Groovy provides statically type check
@groovy.transform.TypeChecked
void method() {
// do nothing
}
​

11. Groovy Basics

12. Groovy Shell

13. Omission of get/set methods
​class Person {
String name
String email
}
def person = new Person(name: 'me')
person.email = 'email@domain.com'
println person.name// me
println person.email// email@domain.com
​

14. Initializing beans with named parameters
​class Person {
String name
String email
}
def person = new Person(name: 'me')
person.email = 'email@domain.com'
println person.name// me
println person.email// email@domain.com
​

15. Context operations using with
class Person {
String name
String email
}
def person = new Person(name: 'me',
email: 'email@domain.com')
person.with{
println name// me
println email// email@domain.com
}

16. GStrings (interpolation, multiline)
def param = 'param'
def groovyString = """
There is a ‘${param}’ param
"""
println groovyString​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​// There is a
‘param’ param

17. Native syntax for data structures
def list = [1, 4, 6, 9]
println list[-2] // 6
def map = [UA: 'Ukraine', UK: 'United
Kingdom']
println map.UA // Ukraine
​def range = 10..20
println range[2] //12
​

18. Elvis operator for default values
def name = null
println name != null ? name : "Unknown"
// Unknown
println name ?: "Unknown" // Unknown
name = 'name'
println name ?: "Unknown" // name

19. Safe graph navigation
if (order != null) {
if (order.getCustomer() != null) {
if (order.getCustomer().getAddress() !=
null) {
Address address;
address = order.getCustomer().getAddress()
System.out.println(address);
}
}
}
println order?.customer?.address
​

20. Closures
printSum = { a, b -> print a+b }
printSum(5, 7)// 12
upperCasedList = ['a','b','c','d'].
collect{
it.toUpperCase()
}
println upperCasedList // A, B, C, D
​

21. Metaprogramming
String.metaClass.cons2var = { ->
String res = ''
delegate.toLowerCase()
.tokenize('_')
.each{ s ->
res+=res?s.capitalize():s
}
res
}
println "SAMPLE_VAR".cons2var()
//sampleVar

22. Groovy Infrastructure

23. Gradle - http://gradle.org/
● Strong yet flexible conventions
● Manageable and understandable builds
● Follows convention over configuration approach
● Great plug-ins ecosystem

24. Spock - https://github.com/spockframework/spock
● Testing and specification framework
● JUnit compatible
● Highly expressive specification language

25. Easyb - http://easyb.org/
● Behavior driven development framework
● Specifications are written in Groovy and run via a Java runner,
command line, Maven or Ant
● Supports a few different styles of specifications ranging from
RSpec's it to a story based DSL with givens, whens, and thens

26. Grails - http://grails.org/
● Grails is an Open Source, full stack web
application framework for the JVM
● Based on Spring, Hibernate, Sitemesh, Quartz
etc.
● There are a lot of plug-ins

27. Griffon - http://griffon.codehaus.org
● Desktop development framework inspired in Grails
● Primarily Swing based however supports SWT,
Pivot, GTK and JavaFX too
● Growing plugin system (80+ plugins)

28. Gaelyk - http://gaelyk.appspot.com
● Google App Engine development framework
based on Groovy and Groovlets
● Emerging plugin system

29. GPars - http://gpars.codehaus.org/
● Provides DSL and concurrent friendly methods for
collections
● Supports Actors and STM
● Dataflow concurrency model

30. CodeNarc - http://codenarc.sourceforge.net/
● Static analysis for Groovy code
● Over 175 rules to detect defects, bad practices,
style issues etc.
● Build tools and Sonar integration

31. GVM - http://gvmtool.net/
● Manages parallel Versions of multiple SDKs
● Convenient command line interface
● Inspired by RVM
● Supports Groovy, Grails, Gradle etc
● Unfortunately does not work for Win

32. GroovyServ - http://kobo.github.io/groovyserv/
● Improves Groovy’s startup time
● Works for Win

34. Getting Started

35. http://groovy.codehaus.org/

36. Groovy in Action*
by Dierk König
● Groovy committer since
2004
● Frequent conference
speaker
● Contributor to several agile
and testing books

37. Programming Groovy 2
by Venkat Subramaniam
● An award-winning author
● Famous Agile Guru
● Frequent conference
speaker

39. Thank You!
Groovy
and
Noteworthy
Izzet Mustafayev@EPAM Systems
@webdizz
http://webdizz.name