Groovy for Java developers

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.

Ok, what’s the

Groovy history?

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

Try some Groovy scripts onhttp://www.groovyconsole.appspot.com/

Integerx=10defy=10

printlnx.classprintlny.class

Typing

defx=[]

x.add10x.add5x.add3x.add0.5x.add11.3

printlnx.sort()

Collections are friends of mine

Collections are friends of mine

defx=[:]

x.putAt('name','Daniel')

printlnx

Magic methods

defx=['Daniel','Juliana','Alice','Davi']

x.each{printlnit}

Magic methodsdefmembers=['Daniel','Juliana','Alice','Davi']

deffamilyPositions=[:]

members.each{member->switch(member){case'Alice':case'Davi':familyPositions[member]='child'break

case'Daniel':case'Juliana':familyPositions[member]='parents'break}}

printlnfamilyPositions

defstudent=false

assert!student

Wonderful operators

defstudent=[[name:'Daniel',age:26],[name:'Juliana',age:26]]

printlnstudent*.nameassertstudent*.age==[26,26]

Wonderful operators

classStudent{Stringnameintmark}Studentdaniel=newStudent(name:'Daniel',mark:100)assertdanielasStudent

printlndaniel.markprintlndaniel.name

daniel.setName('DanielFernandes')

printlndaniel.name

Wonderful operators

classStudent{Stringnameintmark

defisApproved(){mark>=70?:false}}Studentdaniel=newStudent(name:'Daniel',mark:100)daniel.isApproved()

Wonderful operators

classStudent{Stringnameintmark

defisApproved(){mark>=70?:false}}

List<Student>students=[newStudent(name:'DanielFernandes',mark:97),newStudent(name:'JulianaFernandes',mark:100)]

//Studentdaniel=students.find{it.name=='Daniel'}defdaniel=students.find{it.name=='Daniel'}printlndaniel?.mark

defdanielFernandes=students.find{it.name=='DanielFernandes'}printlndanielFernandes?.mark

Wonderful operators

classStudent{Stringnameintmark}

List<Student>students=[newStudent(name:'DanielFernandes'),newStudent(name:'JulianaFernandes',mark:100)]

assert'DanielFernandes'instudents.nameassert'JoãoBatista'instudents.name

Wonderful operators

defbrasil=newXmlParser().parseText(newFile('/home/daniel/Dropbox/Public/brasil.xml').text)

defestados=brasil.estados.estadoassertestados.size()==27

defcidades=estados*.cidades*.cidadeassertcidades*.size().sum()==5564

XML isn’t a PITA anymore

JSON for the clever guysimportgroovy.json.JsonSlurper

defpersons=newJsonSlurper().parseText('[{"name":"Daniel"},{"name":"Juliana"}]')

printlnpersons*.name

Anyone.hasQuestions()

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’