How Scala, Wicket, and Java EE Can Improve Web Development

How Wicket, Scala, and
Java EE Can Improve
Web Development
Bruno Borges
Oracle Product Manager for Latin America
Java EE, GlassFish, WebLogic, Coherence


Who am I?
Bruno Borges

 Java developer since 2000
 Speaker at Conferences
– JustJava, JavaOne Brazil, The Developers Conference, ApacheCon
 Evangelized Apache Camel and Apache Wicket in Brazil
 Joined Oracle on July 2012
– Product Manager for Java EE, GlassFish and WebLogic
 Married, lives in Sao Paulo, has a Golden Retriever, hiker and gamer


Agenda

 All about Web Development
 Apache Wicket Overview
 Introducing Scala and the Gamboa Wicket DSL
 Java EE for everything
 The Gamboa Project


All About Web
Development


Web designing process and tools
Mock, draw, code


PREVIEW
IN THE
BROWSER

All about Web Development
How do we build web sites and applications?

 There are two ways to build web applications
– bottom-up
 Mock up interfaces, develop using a web framework, apply design
– top-down
 Design pixel-perfect prototype, adapt prototype to a web framework,
 There’s no web framework able to do both… productively speaking
 Pixel-perfect websites vs functional websites


Outside the Java Web Framework Land
What are the technologies people use to build pixel-perfect sites?

 Ruby on Rails
 PHP
 Python
– Django Framework
 JavaScript + REST
– ExtJS
– jQuery


What about functional websites?
Component-based frameworks work better

 Java Server Faces
 GWT, Vaadin
 Apache Wicket
 others

 Better use the bottom up design strategy


Java Frameworks for Pixel Perfect Websites
Frameworks that are good for pixel-perfect websites

 JSP / Servlets
 Struts 2, Tapestry, Wicket
 Java Server Faces, specifically Facelets
 Play!, Lift
 others

 Better use the top down design strategy


What if we could have a framework that doesn’t force us
to totally modify the work of a Web Designer for
prototype?


Imperative vs Declarative HTML Markup
What is the best HTML markup for pixel-perfect websites?

 Pixel-perfect websites are always top-down
– A lot of work to add server-side code to the prototype
– And it would be good for web designers to continue to have a functional
prototype after server-side code is added

 Imperative
– Must change from raw HTML markup to specific web framework markup
 Declarative
– Annotates markup to be accessed, and modified, later by the framework


Imperative Markup

Before
<form action=”save”>
<input type=”text” name=”name” />
<input type=”submit” value=”Save” />
</form>
After, using Apache Struts
<s:form action=”save”>
<s:input property=”name” />
<s:submit value=”Save” />
</s:form>


Does it run on the browser?
Not really…

 Imperative frameworks that modify the prototype
– Web designers loose ability to preview in the browser
– They must install, configure and run
 Servlet containers, Ruby, or PHP servers

 You really don’t want web designers touching server-side code
 Specially programmers modifying HTML or CSS elements to fix things


Declarative Markup

Before
<form action=”save”>
<input type=”text” name=”name” />
<input type=”submit” value=”Save” />
</form>
After, using Apache Wicket
<form wicket:id=”form”>
<input type=”text” wicket:id=”name” />
<input type=”submit” value=”Save” wicket:id=”save” />
</form>


Programmers and Developers
Happily Ever After…

 Programmers focused on server-side programming
 Web Designers able to modify client-side without messing server-side
 Preview in the browser

 Customer happy to see (statically) how the application is progressing
– Open Firefox, go to file:///home/customer/project/web/index.html


Apache Wicket
Quick overview


HTML Prototype
The final product from the Web Designer

/MyHomePage.html
<html>
<head><title>Apache Wicket</title></head>
<body>
<span>some message</span>
<form>
Name: <input type=”text” />
Email: <input type=”text” />
<input type=”submit” value=”Send” />
</form>
</body>
</html>


HTML Prototype
The final product from the Web Designer

/MyHomePage.html
<html>
<head><title>Apache Wicket</title></head>
<body>
<span wicket:id=”msg”>some message</span>
<form wicket:id=”form”>
Name: <input type=”text” wicket:id=”name” />
Email: <input type=”text” wicket:id=”email” />
<input type=”submit” value=”Send” />
</form>
</body>
</html>


Java side
Where all the magic happens, object oriented

/MyHomePage.java
public class MyHomePage extends WebPage {
public HomePage() {
add(new Label(“msg”, “JavaOne”));
Form form = new Form(“form”) {
public void onSubmit() { usrBean.salvar(getModelObject());
}};
form.add(new TextField(“name”));
form.add(new TextField(“email”));
form.setModel(new CompoundPropertyModel(new User()));
add(form);
}
}

Easily Extensible

 Just add the JAR with extra
components to the classpath

Gmap2 gmap = new Gmap2(“map”);
page.add(gmap);
<div wicket:id=”map”>
Google Maps
</div>


Apache Wicket
And so many other features

 jQuery as its client-side engine for
– Core components
– Ajax
– WebSockets
 Page composition by: Inheritance, Borders and Panels
 Integration with CDI
 Back button support
 Several components, and also the WicketStuff Community


Scala Language


Scala Language
Quick introduction

 Object Oriented and Functional Language
var foo = 8
 Runs on JVM foo = “bar”
 Statically typed
 Compiles to Java byte code (sweeeet)
 Extensible Type mismatch;
found: String(“bar”)
 Easy to define custom DSLs required: Int


Scala Language
Functions

 They are objects as well

val func = () ⇒ println(“functional programming”)

def callF(paramF: () ⇒ Unit) = paramF()

callF(func)


Scala Language
Very smart constructions

 They may seem complex, but you get used to them

val list1to9 = 1 to 9 toList

for (i ← list1to9) {
print(i)
}

list1to9.foreach(i ⇒ print(i))


Scala Language

val listA = List(1, 2)
val listB = List(3, 4)
val listC = listA :: listB
// listC is a new List object

val listD = listC :: 5
print(listD)
// output: List(1,2,3,4,5)


Scala Language

val map = new HashMap[Int, String]
map += 1 → "Number 1"
println(map(2))
// '2' is the key, not the index!

val romans = Map(1 → "I", 2 → "II", 3 → "III", 4 →
"IV", 5 → "V")
println(romanNumeral(4)) // outputs: "IV"


Back to Wicket
Strong use of anonymous classes

 Wicket programming model resembles Swing
 Pushes developers to use anonymous, inner classes

 Functional programming fits quite well into this model
 Less code, less verbosity

 Scala #win


Wicket + Scala: perfect combination
Before, in Java
/MyHomePage.java
public class MyHomePage extends WebPage {
@Inject private MyService service;
public MyHomePage() {
add(new Label(“msg”, “JavaOne”));
Form form = new Form(“form”, new CompoudPropertyModel(new User())){
public void onSubmit() {
service.update(getModelObject());
}
};
form.add(new TextField(“name”));
form.add(new TextField(“email”));
add(form);
}
}


Now, with Scala
/MyHomePage.scala
class MyHomePage extends WebPage {
@Inject var service: MyService = _
add(new Label(“msg”, “JavaOne”))
object form extends Form(“form”,
new CompoundPropertyModel(new User())) {
add(new TextField(“name”))
add(new TextField(“email”))
override def onSubmit() = {
service.update(getModelObject())
}
}
add(form)
}


Now with specific Scala DSL for Wicket
/MyHomePage.scala
class MyHomePage extends WebPage with DSLWicket {
@Inject var service: MyService = _
label(“msg”, “JavaOne”)
val f = form(“form”, () ⇒ service.update(f.mobject))
f.scmodel(new User())
f.textField[String](“name”)
f.textField[String](“email”)
}


Java EE
for everything else


Java EE 6
Filling the necessary gaps, extraordinarily well

 Enterprise Java Beans
 Contexts and Dependency Injection
 Java Persistent API
 Java Transaction API
 Bean Validation
 JAX-RS


And more stuff
Like…

 GlassFish Maven Embedded Plugin
 Derby DB
 No more web.xml
– Servlet 3.0 is awesome
 Getters/Setters generated
– Scala’s @BeanProperty annotation


No more web.xml
Servlet 3 and Scala

package code.webapp

import javax.servlet.annotation.{ WebFilter, WebInitParam }
import org.apache.wicket.protocol.http.WicketFilter

@WebFilter(value = Array("/*"), initParams = Array(
new WebInitParam(name="applicationClassName", value="code.webapp.Application"),
new WebInitParam(name="filterMappingUrlPattern", value = "/*“)
))

class GamboaApplication extends WicketFilter


Getters/Setters generated
Scala’s @BeanProperty annotation

package code.data

import scala.reflect.BeanProperty
import javax.persistence.{ Id, GeneratedValue }

trait Identifiable extends Serializable {
@Id @GeneratedValue @BeanProperty var id: String = _
}


Getters/Setters generated
Scala’s @BeanProperty annotation

package code.data

import scala.reflect.BeanProperty
import javax.persistence.{ Entity, Table }

@Entity
@Table(name = “USERS”)
class User extends Identifiable {
@BeanProperty var name: String = _
@BeanProperty var email: String = _
}


Gamboa Project
Great architecture, written an archetype must be!

Apache Wicket
+ Java EE 6
+ Scala
Gamboa Project
www.gamboa-project.org


Gamboa Project
Maven archetypes

 Scala DSL for Wicket
 3 archetypes
– Java EE archetype
 JPA, CDI, EJB3, GlassFish Maven Plugin integrated
– Spring with CouchDB
– Spring with MongoDB
 Both integrated with Jetty plugin
 Directory structure simplified for Web development
– Not really “Maven convention”, for good reason

Gamboa Demo
Group Birthday


Next time you choose a web framework, think not only
about features, but also about the web development
process and the type of website you are going to build.


QUESTIONS?


THANK YOU!
@brunoborges
blogs.oracle.com/brunoborges


The preceding is intended to outline our general product direction. It is intended
for information purposes only, and may not be incorporated into any contract.
It is not a commitment to deliver any material, code, or functionality, and should
not be relied upon in making purchasing decisions. The development, release,
and timing of any features or functionality described for Oracle’s products
remains at the sole discretion of Oracle.


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