Agile Web Development with Groovy & Grails

Groovy

3© 2008 BearingPoint, Inc.

Groovy

Why?


Groovy

Java Jobs


Groovy

Java EE Jobs


Groovy

Ruby On Rails Jobs


Groovy

JSR 241


Groovy

„Java-stylish with a Ruby-esque feeling“


Groovy

„Groovy is not a replacement for the Java programming language; it‘s a complement to that language“

Richard Monson-Haefel, award winning author & technical analyst

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© 2008 BearingPoint, Inc.

Groovy

GroovyBeans

class GroovyBean {String name

}

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Groovy

Autoboxing

def b = new GroovyBean()b.name = “groovy bean“

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© 2008 BearingPoint, Inc. 12

Groovy

Duck Typing„When I see a bird that walks like a

duck and swims like a duck and quacks like a duck, I call that bird a duck.“Poem by James Whitcomb Riley

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Groovy

Expressiveness

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Groovy

Java:java.net.URLEncoder.encode(“a b“);

Groovy:URLEncoder.encode ‘a b‘

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Groovy

GStrings

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Groovy

def name = “world“def message = “Hello ${name}“

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Groovy

def text = “““Ein längerer Stringmit Zeilenumbrüchen

“““

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Groovy

Native Lists, Maps, Regex

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Groovy

def aList = []

def myList = [22,55,33]

Lists

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Groovy

def emptyMap = [:]

def myMap = [“name“: “Max“, “age“ : “33“ ]

Maps

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Groovy

myMap.name == “Max“

myMap[“age“] == “33“

Maps

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Groovy

“cheesecheese“ =~ “cheese“ “cheesecheese“ =~ /cheese/

“potatoe“ ==~ /potatoe?/ “potato“ ==~ /potatoe?/

Regular Expressions

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Groovy

Loopsfor (int i=0;i<6;i++) {}

for (i in 0..9) {}

def list = [1, 2, 3]for (i in list) {}

10.times {}

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Groovy

Closures

def myClosure = { /* do something */}

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Groovy

[3,1,2].each { print “value:“+it}

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Groovy

Buildersdef xml = new groovy.xml.MarkupBuilder()

xml.authors {

author(name:‘Stephen King‘) {

book(title:‘The Shining‘)

book(title:‘The Stand‘)

}

author(name:‘James Patterson‘) {

book(title:‘Along Came a Spider‘)

}

}

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Groovy

Builders<authors>

<author name=“Stephen King“>

<book title=“The Shining“ />

<book title=“The Stand“ />

</author>

<author name=“James Patterson“>

<book title=“Along Came a Spider“ />

<author>

<authors>

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Groovy

The Groovy Truth

if (myString != null && myString.length() > 0) {myMethod(myString);}

if (myString) myMethod(myString)

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Groovy

Save DereferencingLong id=null;if (session.getAttribute(“user“) != null) {id = ((User) session.getAttribute(“user“)).getId();}

def id = session.user?.id

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Groovy

Meta Class Concept

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Groovy

IDE Integration

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Groovy

Domain Specific Language (DSL)

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Groovy

Java:public class RecursiveFileReading {

public static void main(String[] args) { printAllFiles(new File(".")); } public static final void printAllFiles(File root) { File[] allChildren = root.listFiles(); for (File child : allChildren) { if (child.isDirectory()) { RecursiveFileReading.printAllFiles(child); } else { System.out.println(child.toString()); } } }}

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Groovy

Groovy:groovy -e “new File(‘.‘).eachFileRecurse { println it }“

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Groovy

„There is a value for learning Groovy for its own sake. It will open your mind...“

Grails

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Grails

Rapid Application Develoment(RAD)

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Grails

Full Stack Framework

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Grails

Convention Over Configuration(CoC)

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Grails

RESTfullRepresentational State Transfer

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Grails

GET

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Grails

POST

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Grails

PUT

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Grails

DELETE

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Grails

HEAD

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Grails

OPTIONS

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Grails

http://localhost:8080/application/user/profile/123

Controller IDAction

RESTfull

http://localhost/myapp/user/signin

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Grails

DRY Paradigm(Don‘t Repeat Yourself)

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Grails

Leverages existing hardware

Leverages existing Java/Framework knowledge

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Grails

Components

Java Virtual Machine

Java Language

Java EE

JDK

Grails

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Grails

UI, AJAX & RIA Frameworks

GWTYUI

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Grails

Plugin API JSF

Struts

JMS

ACEGI/Spring Security, JSecurity

OpenID

Functional Testing (Canoo WebTest)

Apache Axis 2, XFire

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Grails

GORMGroovy Object-Relational Mapping

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class Book { String title}


Grails

GORM

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class Book {String author String title Date releaseDate

static constraints = { author(blank:false, size:2..30) releaseDate(nullable: true) }

}


Grails

GORM

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def book = new Book()

book.author = “author A“book.title = “title 1“

book.save()


Grails

GORM

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def book = new Book()

book.author = “author A“book.title = “title 1“

if (book.save()) {/* successfull flow */} else {/* error flow */}


Grails

GORM

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Grails

(Dynamic) Finders

def macBook = Book.get(1)

def macBook = Book.findByTitle(“MacBook“)

def macBook = Book.findByTitleAndAuthor(“MacBook“, “Apple“)

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<h1>Book list</h1><table> <tr> <th>Title</th> <th>Author</th> </tr><g:each in="${books}"> <tr> <td>${it.title}</td>

<td>${it.author}</td> </tr>

</g:each> </table>


Grails

Groovy Server Pages (GSP)

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<g:if test="${name == 'fred'}"> Hello Fred!</g:if><g:else> Hello ${name}! Do I know you?</g:else>


Grails


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<g:datePicker name="myDate" value="${new Date()}"

precision="day" years="${1930..1970}"/>


Grails


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Grails

Scaffolding

Dynamic Scaffolding

Static Scaffolding

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Grails

How does it look like?

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Grails

Success Stories?

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Grails

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Grails

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Grails

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Grails

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Grails

http://groovy.codehaus.org/

http://www.grails.org

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Grails

Dirk König - Groovy In ActionManning, 2007

Graeme Keith Rocher - The Definitive Guide To GrailsApress, 2006

Agile Web Development with Groovy & Grails

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