Introduction to Grails , Groovs vs Java, Grails vs Rails

1. GRAILS
Ezgi AYVAZOGLUApril 2014 - IZMIR

2. Content
 What is Grails?
 Why full stack?
 What is Groovy?
 Grails vs Rails
 Groovy vs Java
 Testing in Grails
 Examples

3. Grails ( on Rails) is an
 Open Source,
 full stack,
 web application framework for the Java Virtual
Machine.
It uses the Groovy programming language which
is an
agile, object oriented & dynamic programming
language
for the Java Virtual Machine.
What is Grails?

4. What is Grails?
Rapid Web Application Development Framework
 For the JVM,
 Inspired by Ruby on Rails, Django and others.

5. What is Grails?
 Convention over Configuration (CoC),
 Don’t Repeat Yourself (DRY).

6. Grails Architecture

7. How Grails is full stack
framework?-1
Normally when you build applications, you
need…
 Database management (ORM)
 Presentation (User Interface)
 Service Layer
 Configuration
Grails will provide you functionality to all
those areas so you don't need to look for a
set of frameworks, just use one.

8. Grails attempts to solve as many pieces of
the web development puzzle through the core
technology and its associated plug-ins.
 An easy to use Object Relational Mapping
(ORM) layer built on Hibernate,
 An expressive view technology called Groovy
Server Pages (GSP),
 A controller layer built on Spring MVC,
How Grails is full stack
framework?-2

9. A controller layer built on Spring
MVC?
 Basic controller logic,
 Data binding and validation,
 Runtime configurations,
 Transactions.

10.  A command line scripting environment built on
the Groovy-powered Gant,
 An embedded Tomcat container which is
configured for on the fly reloading,
 Dependency injection with the inbuilt Spring
container,
How Grails is full stack
framework?-3

11.  Support for internationalization (i18n) built on
Spring's core MessageSource concept,
 A transactional service layer built on Spring's
transaction abstraction.
How Grails is full stack
framework?-4

12.  All of these are
made easy to use
through the power of
the Groovy language
and the extensive use
of
Domain Specific
Languages (DSLs)
Why full stack?

13. Groovy

14. What is Groovy?
 Groovy is an object-oriented programming
language for the Java platform.
 It is a dynamic language with features similar
to those of Python, Ruby, Perl, and Smalltalk.
 It can be used as a scripting language for the
Java Platform, is dynamically compiled to Java
Virtual Machine (JVM).

15. Grails vs Rails

16. Grails vs Rails - 1
 Groovy vs Ruby
 API documentation better than Rails
 Solid frameworks underneath, such as spring,
hibernate
 Both has a active community, Rails more
popular, and more jobs, more books.

17. Grails vs Rails - 2
 DB Migrations
 GORM vs Active Record
 REST
 Faster than Rails, but used lot of memory,
cheaper hosting
 Rails mature than Grails
 Rails release/update more often

18. Groovy vs Java

19. Default imports
 java.io.*
 java.lang.*
 java.math.BigDecimal
 java.math.BigInteger
 java.net.*
 java.util.*
 groovy.lang.*
 groovy.util.*
Groovy vs Java -1

20. Groovy vs Java - 2
 Closures
 Native syntax for lists and maps
 GroovyMarkup and GPath support
 Native support for regular expressions
 Polymorphic iteration and powerful switch
statement
 Dynamic and static typing is supported - so
you can omit the type declarations on methods,
fields and variables
def clos = { println "hello!" }
clos() //prints "hello!"

21. In Java:
 for (int i=0; i < len; i++) {...}
In Groovy
 for (i in 0..len-1) {...} or
 for (i in 0..<len) {...} or
 len.times {...}.
Groovy vs Java - 3

22.  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. You can use
the this keyword inside static methods (which
refers to this class).
 Methods and classes are public by default.
Protected in Groovy has the same meaning as
protected in Java.
Groovy vs Java - 4

23. Groovy vs Java - 5

24. Testing

25. Testing
 Integration
To execute the JUnit integration tests you can
run:
grails test-app integration:integration
 Unit
The following command will run all test types
in the
unit phase:
grails test-app unit:

26. Testing - Spock
 Spock is a testing and specification framework
for Java and Groovy applications.
 What makes it stand out from the crowd is its
beautiful and highly expressive specification
language.
 This plug-in brings the power of Spock to
Grails.
grails test-app :spock

27.  To run the all of the spock tests in the functional
phase you would run.
grails test-app functional:spock
 More than one pattern can be specified.
grails test-app unit:spock integration:spock
 Test and type/phase targetting can be applied at
the same time:
grails test-app integration: unit: some.org.**.*
(This would run all tests in the integration and unit
phases
that are in the package some.org or a subpackage.)
Testing - Spock

28. Tools
 IDE: GGTS, Eclipse 3.5、NetBeans 6.8、
IDEA 9、Spring STS 2.3.0
 Editor：E-Texteditor、Textmate、GEdit
 Build：Maven、Ant、Ivy
 WebContainer：Tomcat、Jetty
 Database：HSQL、MySQL
 GRAG

29. GGTS
 The Groovy/Grails Tool Suite provides the best
Eclipse-powered development environment for
building Groovy and Grails applications.
 GGTS provides support for the latest versions
of Groovy and Grails, and comes on top of the
latest Eclipse releases.

30. GGTS

31. Demo
Grails gTunes:
1) grails create-app gTunes
2) grails create-controller store
3) edit StoreController.groovy
4) write -> controller.index()
assert 'Welcome to the gTunes store!'==
response.text
5) grails run-app

32. Demo
http://localhost:8080/gTunes/

33. Examples
 http://www.nowtv.com/
 https://wwws.citruslane.com/#index
 http://www.vodafone.co.uk/
 http://grails.org/
 http://uros.com/
 …
 Twitter in 60 minutes!
http://www.youtube.com/watch?v=pmT1zg8Cie4

34. Summary
=
+
+

35. Summary
 Grails is built on proven & solid OSS bricks
 Spring: IoC, DI, Spring MVC, transactions…
 Hibernate: ORM, querying mechanism
 Groovy: for everything that matters
 SiteMesh: page layout and composition
 Quartz: for job scheduling
 AJAX: integration with different libraries
 Jetty & HSQLDB: for fast development cycles

36. Has it got to be complex?
 But it’s slow to start with
 Seting up the project takes time
 It gets complicated pretty rapidly
 Dive into Spring & Hibernate to wire
everything together
 There are so many layers
 DAOs, DTOs, more abstraction
layers
 Too many configuration files
 Often too much XML for everything
Struts / Spring / Hibernate is okay…

37. Thank You
Any question
Ezgi AYVAZOGLU