talk i gave @Botzia

1. Introduction to Grails
By Avi Perez

2.  Groovy at Glance
◦ Features
◦ Data Types
◦ Closures
◦ Advance Examples
 Grails
 Demo
Outline

3. ◦ Agile and Dynamic language
◦ JVM bounded – compiled to java byte code
◦ Increase productivity
 Java developers - almost-zero learning curve
 Simplifies testing
 Reducing scaffolding code
◦ Current version 2.0
◦ performance issues
Groovy at Glance
Intoduction

4.  Semicolons are optional. Use them if you like
(though you must use them to put several
statements on one line).
 The return keyword is optional.
 Methods and classes are public by default.
 Inner classes use closures instead.
Groovy at Glance
Intoduction

5.  The throws clause in a method signature is
not checked by the Groovy compiler, because
there is no difference between checked and
unchecked exceptions
 Groovy supports regular expressions natively
Groovy at Glance
Intoduction

6.  Lists:
◦ def list= [9, 4, 2, 10, 5]
◦ assert list.max() == 10
◦ assert list.min() == 2
◦ assert [6,3,9,2,7,1,5].sort() == [1,2,3,5,6,7,9]
◦ assert [1,2,3].reverse() == [3,2,1]
◦ assert 5..8 == [5,6,7,8]
◦ assert ('a'..'g')[ 3..5 ] == ['d','e','f']
 Dates Formats:
◦ def date = new Date().parse('yyyy/MM/dd', '1973/07/09')
Groovy at Glance
Hands on…

7.  Maps
◦ def family = [dad:"John" , mom:"Jane", son:"John"]
◦ GPath notation
 def x = [ ['a':11, 'b':12], ['a':21, 'b':22] ]
assert x.a == [11, 21]
 assert [ 'a', 7, 'b', [2,3] ].groupBy{ it.class } ==
[ (String.class): ['a', 'b'], (Integer.class): [ 7 ], (ArrayList.class): [[2,3]] ]
Groovy at Glance
Intoduction

8.  Closures
◦ a "code block" or a method pointer that is defined and then
executed at a later point
◦ Simple Examples
 def clos = { println “Hey Groovy!" }
clos() //prints “Hey Groovy!“
 def closure = { param -> param + 1 }
def answer = [1, 2].collect(closure)
assert answer == [2, 3]
Groovy at Glance
Intoduction

9.  Methods returning
def geocode(String location)
{
// implementation
return [48.824068, 2.531733] //for Paris, France
}
def (lat, long) = geocode("Paris, France")
assert lat == 48.824068 assert long == 2.531733
 Safe navigation
◦ def foo = null
◦ def bar = foo?.something?.myMethod()
Groovy at Glance
Hands on…

10.  Regular Expressions support
 Extracting Hashtags from twitter:
◦ def val=“Every time #Israel is attacked their land expands, but they have not yet
received all the land #God promised them http://tinyurl.com/2fr96y6”
◦ def hashTags = val.findAll("#[A-Za-z0-9_]+")
Groovy at Glance
Hands on…

11.  Constructing Objects
Class Expando{
def name
def location
def id
}
def bean = new Expando(name:"James", location:"London", id:123)
Groovy at Glance
Hands on…

12.  File IO
◦ Text
def fileContent = new File(fileName).text
◦ EachLine
Nik.txt
My name is Ayush.
But you can call me Nik.
I am fully devoted to Java and want to something extra for java
def number=new File ('Nik.txt').eachLine {
line -> number++
println "$number: $line"
Groovy at Glance
Hands on…

13.  static def CAR_RECORDS = ''' <records>
 <car name="HSV Maloo" make="Holden" year="2006">
 <country>Australia</country>
 <record type="speed">Production Pickup Truck with speed of
271kph</record>
 </car>
 <car name="P50" make="Peel" year="1962">
 <country>Isle of Man</country>
 <record type="size">Smallest Street-Legal Car at 99cm wide and 59 kg in
weight</record>
 </car>
 <car name="Royale" make="Bugatti" year="1931">
 <country>France</country>
 <record type="price">Most Valuable Car at $15 million</record>
 </car>
 </records> '''
Groovy at Glance
Hands on…

14.  XML Parsing XmlSluper (Similar to JSON parsing
JSONSluper() )
def records = new
XmlSlurper().parseText(XmlExamples.CAR_RECORDS)
◦ All Elements:
def allRecords = records.car
◦ Counting children:
assert 3 == allRecords.size() def allNodes =
records.depthFirst().collect{ it }
Groovy at Glance
Hands on…

15.  Groovy at Glance
◦ Features
◦ Data Types
◦ Closures
◦ Advance Examples
 Grails
 Demo
Outline

16.  Grails
◦ Open source web application platform
◦ Convention over Configuration
 Any grails application looks the same
 No need for XML mapping files
◦ Powerful MVC framework
 Power by Spring and Hibernate
 Model / Domain Layer
 View Layer (GSP)
 Controller
Introduction Grails

17. Introduction Grails
Grails Architecture

18.  Convention over configuration
◦ Domains – Model layer
◦ Controller – Controller layer
◦ Views – Groovy server pages
◦ Taglib – Dynamic Tag libararies
◦ Services – Service layer
◦ Conf – all configuration sources
◦ I18n
Introduction Grails
Grails Architecture

19.  POGO
 GORM Support
Introduction Grails
Models….

20. Introduction Grails
Controllers….

21. Introduction Grails
Services….

22. Introduction Grails
Testing….

23.  conf/DataSource.groovy
◦ Data Base Connections
 conf/UrlMapping.groovy
◦ Web application rounting
 conf/Config.groovy
◦ General configurations(mime mapping,logging)
 conf/BuildConfig.groovy
◦ Ivymaven dependencies
Introduction Grails
Configurations….

25.  Groovy at Glance
◦ Features
◦ Data Types
◦ Closures
◦ Advance Examples
 Grails
 Demo
Outline