- Groovy is an agile and dynamic language for the Java Virtual Machine that builds on Java's strengths with additional features from languages like Python, Ruby and Smalltalk. It provides features to Java developers with almost no learning curve. - Groovy supports dynamic and static typing, collections, magic methods, operators that simplify operations like finding and filtering, and processing XML and JSON easily. - Examples demonstrate how Groovy can be used to process collections, define classes and methods, parse XML and JSON, and more.

1. Groovy for Java developers

2. Agenda:
- A short history;
- Typing;
- Collections are friends of mine;
- Magic methods;
- Wonderful operators;
- XML isn’t a PITA anymore;
- JSON for the clever guys.

3. Ok, what’s the
Groovy history?

4. Groovy...
is an agile and dynamic language for the Java Virtual Machine
builds upon the strengths of Java but has additional power features inspired by languages like Python, Ruby and Smalltalk
makes modern programming features available to Java developers with almost-zero learning curve
provides the ability to statically type check and statically compile your code for robustness and performance
supports Domain-Specific Languages and other compact syntax so your code becomes easy to read and maintain
makes writing shell and build scripts easy with its powerful processing primitives, OO abilities and an Ant DSL
increases developer productivity by reducing scaffolding code when developing web, GUI, database or console applications
simplifies testing by supporting unit testing and mocking out-of-the-box
seamlessly integrates with all existing Java classes and libraries
compiles straight to Java bytecode so you can use it anywhere you can use Java

5. Try some Groovy scripts on
http://www.groovyconsole.appspot.com/

6. Integer x = 10
def y = 10
println x.class
println y.class
Typing

7. def x = []
x.add 10
x.add 5
x.add 3
x.add 0.5
x.add 11.3
println x.sort()
Collections are friends of mine

8. Collections are friends of mine
def x = [:]
x.putAt('name', 'Daniel')
println x

9. Magic methods
def x = ['Daniel', 'Juliana', 'Alice', 'Davi']
x.each {
println it
}

10. Magic methods
def members = ['Daniel', 'Juliana', 'Alice', 'Davi']
def familyPositions = [:]
members.each { member ->
switch(member) {
case 'Alice':
case 'Davi':
familyPositions[member] = 'child'
break
case 'Daniel':
case 'Juliana':
familyPositions[member] = 'parents'
break
}
}
println familyPositions

11. def student = false
assert !student
Wonderful operators

12. def student = [
[name : 'Daniel',age : 26],
[name : 'Juliana',age : 26]
]
println student*.name
assert student*.age == [26,26]
Wonderful operators

13. class Student {
String name
int mark
}
Student daniel = new Student(name: 'Daniel', mark: 100)
assert daniel as Student
println daniel.mark
println daniel.name
daniel.setName('Daniel Fernandes')
println daniel.name
Wonderful operators

14. class Student {
String name
int mark
def isApproved() {
mark >= 70 ?: false
}
}
Student daniel = new Student(name: 'Daniel', mark: 100)
daniel.isApproved()
Wonderful operators

15. class Student {
String name
int mark
def isApproved() {
mark >= 70 ?: false
}
}
List<Student> students = [
new Student(name : 'Daniel Fernandes', mark : 97),
new Student(name : 'Juliana Fernandes', mark : 100)
]
//Student daniel = students.find{ it.name == 'Daniel' }
def daniel = students.find{ it.name == 'Daniel' }
println daniel?.mark
def danielFernandes = students.find{ it.name == 'Daniel Fernandes' }
println danielFernandes?.mark
Wonderful operators

16. class Student {
String name
int mark
}
List<Student> students = [
new Student(name : 'Daniel Fernandes'),
new Student(name : 'Juliana Fernandes',
mark : 100)
]
assert 'Daniel Fernandes' in students.name
assert 'João Batista' in students.name
Wonderful operators

17. def brasil = new XmlParser().parseText(new
File('/home/daniel/Dropbox/Public/brasil.xml').text)
def estados = brasil.estados.estado
assert estados.size() == 27
def cidades = estados*.cidades*.cidade
assert cidades*.size().sum() == 5564
XML isn’t a PITA anymore

18. JSON for the clever guys
import groovy.json.JsonSlurper
def persons = new JsonSlurper().parseText('[{"name":
"Daniel"},{"name": "Juliana"}]')
println persons*.name

19. Anyone.hasQuestions()

20. Thank.to(“you”).to(“listen me”)
def contact = Person.find { it.name == ‘Daniel Fernandes’ }.contact
assert contact.mail == ‘danielpsf@gmail.com’
assert contact.skype == ‘daniel.pedro_fernandes’