SeamFramework.orgCommunity Documentation
The Web Beans Reference Implementation is being developed at the Seam project. You can download the latest developer release of Web Beans from the the downloads page.
The Web Beans RI comes with a two deployable example applications:
webbeans-numberguess
, a war example, containing only
simple beans, and webbeans-translator
an ear example,
containing enterprise beans. To run the examples you'll need the following:
the latest release of the Web Beans RI,
JBoss AS 5.0.0.GA, and
Ant 1.7.0.
Currently, the Web Beans RI only runs on JBoss Application Server 5. You'll need to download JBoss AS 5.0.0.GA from jboss.org, and unzip it. For example:
$ cd /Applications $ unzip ~/jboss-5.0.0.GA.zip
Next, download the Web Beans RI from seamframework.org, and unzip it. For example
$ cd ~/ $ unzip ~/webbeans-$VERSION.zip
Next, we need to tell Web Beans where JBoss is located. Edit
jboss-as/build.properties
and set the
jboss.home
property. For example:
jboss.home=/Applications/jboss-5.0.0.GA
As Web Beans is a new piece of software, you need to update JBoss AS to run the Web Beans RI. Future versions of JBoss AS will include these updates, and this step won't be necessary.
Currently, two updates are needed. Firstly, a new deployer,
webbeans.deployer
is added. This adds supports for
Web Bean archives to JBoss AS, and allows the Web Beans RI to query the
EJB3 container and discover which EJBs are installed in your
application. Secondly, an update to JBoss EJB3 is needed.
To install the update, you'll need Ant 1.7.0 installed, and the
ANT_HOME
environment variable set. For example:
$ unzip apache-ant-1.7.0.zip $ export ANT_HOME=~/apache-ant-1.7.0
Then, you can install the update. The update script will use Maven to download the Web Beans and EJB3 automatically.
$ cd webbeans-$VERSION/jboss-as $ ant update
Now, you're ready to deploy your first example!
The build scripts for the examples offer a number of targets, these are:
ant restart
- deploy the example in exploded
format
ant explode
- update an exploded example, without
restarting the deployment
ant deploy
- deploy the example in compressed jar format
ant undeploy
- remove the example from the server
ant clean
- clean the example
To deploy the numberguess example:
$ cd examples/numberguess ant deploy
Start JBoss AS:
$ /Application/jboss-5.0.0.GA/bin/run.sh
If you use Windows, use the run.bat
script.
Wait for the application to deploy, and enjoy hours of fun at http://localhost:8080/webbeans-numberguess!
The Web Beans RI includes a second simple example that will translate your text into Latin. The numberguess example is a war example, and uses only simple beans; the translator example is an ear example, and includes enterprise beans, packaged in an EJB module. To try it out:
$ cd examples/translator ant deploy
Wait for the application to deploy, and visit http://localhost:8080/webbeans-translator!
In the numberguess application you get given 10 attempts to guess a number between 1 and 100. After each attempt, you will be told whether you are too high, or too low.
The numberguess example is comprised of a number of Web Beans, configuration files, and Facelet JSF pages, packaged as a war. Let's start with the configuration files.
All the configuration files for this example are located in
WEB-INF/
, which is stored in
WebContent
in the source tree. First, we have
faces-config.xml
, in which we tell JSF to use
Facelets:
<?xml version='1.0' encoding='UTF-8'?>
<faces-config version="1.2"
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-facesconfig_1_2.xsd">
<application>
<view-handler>com.sun.facelets.FaceletViewHandler</view-handler>
</application>
</faces-config>
There is an empty web-beans.xml
file, which marks
this application as a Web Beans application.
Finally there is web.xml
:
<?xml version="1.0" encoding="UTF-8"?> <web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"> <display-name>Web Beans Numbergues example</display-name> <!-- JSF --> <servlet><servlet-name>Faces Servlet</servlet-name> <servlet-class>javax.faces.webapp.FacesServlet</servlet-class> <load-on-startup>1</load-on-startup> </servlet> <servlet-ma
pping> <servlet-name>Faces Servlet</servlet-name> <url-pattern>*.jsf</url-pattern> </servlet-mapping> <context-pa
ram> <param-name>javax.faces.DEFAULT_SUFFIX</param-name> <param-value>.xhtml</param-value> </context-param> <session-co
nfig> <session-timeout>10</session-timeout> </session-config> </web-app>
![]() | Enable and load the JSF servlet |
![]() |
Configure requests to |
![]() |
Tell JSF that we will be giving our source files (facelets) an
extension of |
![]() | Configure a session timeout of 10 minutes |
Whilst this demo is a JSF demo, you can use the Web Beans RI with any Servlet based web framework.
Let's take a look at the Facelet view:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xmlns:ui="http://java.sun.com/jsf/facelets" xmlns:h="http://java.sun.com/jsf/html" xmlns:f="http://java.sun.com/jsf/core" xmlns:s="http://jboss.com/products/seam/taglib"> <ui:composition template="template.xhtml"> <ui:define name="content"> <h1>Guess a number...</h1> <h:form id="NumberGuessMain"> <div
style="color: red"> <h:messages id="messages" globalOnly="false"/> <h:outputText id="Higher" value="Higher!" rendered="#{game.number gt game.guess and game.guess ne 0}"/> <h:outputText id="Lower" value="Lower!" rendered="#{game.number lt game.guess and game.guess ne 0}"/> </div> <div> I
'm thinking of a number between #{game.smallest} and #{game.biggest}. You have #{game.remainingGuesses} guesses. </div> <div> Your guess: <
h:inputText id="inputGuess" value="#{game.guess}" required="true" size="3" disabled="#{game.number eq game.guess}">
<f:validateLongRange maximum="#{game.biggest}" minimum="#{game.smallest}"/> </h:inputText> <h
:commandButton id="GuessButton" value="Guess" action="#{game.check}" disabled="#{game.number eq game.guess}"/> </div> <div> <h:commandButton id="RestartButton" value="Reset" action="#{game.reset}" immediate="true" /> </div> </h:form> </ui:define> </ui:composition> </html>
![]() | Facelets is a templating language for JSF, here we are wrapping our page in a template which defines the header. |
![]() | There are a number of messages which can be sent to the user, "Higher!", "Lower!" and "Correct!" |
![]() | As the user guesses, the range of numbers they can guess gets smaller - this sentance changes to make sure they know what range to guess in. |
![]() | This input field is bound to a Web Bean, using the value expression. |
![]() | A range validator is used to make sure the user doesn't accidentally input a number outside of the range in which they can guess - if the validator wasn't here, the user might use up a guess on an out of range number. |
![]() | And, of course, there must be a way for the user to send their guess to the server. Here we bind to an action method on the Web Bean. |
The example exists of 4 classes, the first two of which are binding
types. First, there is the @Random
binding type,
used for injecting a random number:
@Target( { TYPE, METHOD, PARAMETER, FIELD })
@Retention(RUNTIME)
@Documented
@BindingType
public @interface Random {}
There is also the @MaxNumber
binding type, used for
injecting the maximum number that can be injected:
@Target( { TYPE, METHOD, PARAMETER, FIELD })
@Retention(RUNTIME)
@Documented
@BindingType
public @interface MaxNumber {}
The Generator
class is responsible for creating the
random number, via a producer method. It also exposes the maximum
possible number via a producer method:
@ApplicationScoped
public class Generator {
private java.util.Random random = new java.util.Random( System.currentTimeMillis() );
private int maxNumber = 100;
java.util.Random getRandom()
{
return random;
}
@Produces @Random int next() {
return getRandom().nextInt(maxNumber);
}
@Produces @MaxNumber int getMaxNumber()
{
return maxNumber;
}
}
You'll notice that the Generator
is application
scoped; therefore we don't get a different random each time.
The final Web Bean in the application is the session scoped
Game
.
You'll note that we've used the @Named
annotation, so that we can use the bean through EL in the JSF page.
Finally, we've used constructor injection to initialize the game with
a random number. And of course, we need to tell the player when they've
won, so we give feedback with a FacesMessage
.
package org.jboss.webbeans.examples.numberguess;
import javax.annotation.PostConstruct;
import javax.faces.application.FacesMessage;
import javax.faces.context.FacesContext;
import javax.webbeans.AnnotationLiteral;
import javax.webbeans.Current;
import javax.webbeans.Initializer;
import javax.webbeans.Named;
import javax.webbeans.SessionScoped;
import javax.webbeans.manager.Manager;
@Named
@SessionScoped
public class Game
{
private int number;
private int guess;
private int smallest;
private int biggest;
private int remainingGuesses;
@Current Manager manager;
public Game()
{
}
@Initializer
Game(@MaxNumber int maxNumber)
{
this.biggest = maxNumber;
}
public int getNumber()
{
return number;
}
public int getGuess()
{
return guess;
}
public void setGuess(int guess)
{
this.guess = guess;
}
public int getSmallest()
{
return smallest;
}
public int getBiggest()
{
return biggest;
}
public int getRemainingGuesses()
{
return remainingGuesses;
}
public String check()
{
if (guess>number)
{
biggest = guess - 1;
}
if (guess<number)
{
smallest = guess + 1;
}
if (guess == number)
{
FacesContext.getCurrentInstance().addMessage(null, new FacesMessage("Correct!"));
}
remainingGuesses--;
return null;
}
@PostConstruct
public void reset()
{
this.smallest = 0;
this.guess = 0;
this.remainingGuesses = 10;
this.number = manager.getInstanceByType(Integer.class, new AnnotationLiteral<Random>(){});
}
}
The translator example will take any sentences you enter, and translate them to Latin.
The translator example is built as an ear, and contains EJBs. As a result, it's structure is more complex than the numberguess example.
EJB 3.1 and Jave EE 6 allow you to package EJBs in a war, which will make this structure much simpler!
First, let's take a look at the ear aggregator, which is located in
webbeans-translator-ear
module. Maven automatically
generates the application.xml
for us:
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-ear-plugin</artifactId>
<configuration>
<modules>
<webModule>
<groupId>org.jboss.webbeans.examples.translator</groupId>
<artifactId>webbeans-translator-war</artifactId>
<contextRoot>/webbeans-translator</contextRoot>
</webModule>
</modules>
</configuration>
</plugin>
Here we set the context path, which gives us a nice url (http://localhost:8080/webbeans-translator).
If you aren't using Maven to generate these files, you would need
META-INF/application.xml
:
<?xml version="1.0" encoding="UTF-8"?>
<application xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/application_5.xsd"
version="5">
<display-name>webbeans-translator-ear</display-name>
<description>Ear Example for the reference implementation of JSR 299: Web Beans</description>
<module>
<web>
<web-uri>webbeans-translator.war</web-uri>
<context-root>/webbeans-translator</context-root>
</web>
</module>
<module>
<ejb>webbeans-translator.jar</ejb>
</module>
</application>
Next, lets look at the war. Just as in the numberguess example, we have
a faces-config.xml
(to enabled Facelets) and a
web.xml
(to enable JSF) in
WebContent/WEB-INF
.
More intersting is the facelet used to translate text. Just as in the numberguess example we have a template, which surrounds the form (ommitted here for brevity):
<h:form id="NumberGuessMain">
<table>
<tr align="center" style="font-weight: bold" >
<td>
Your text
</td>
<td>
Translation
</td>
</tr>
<tr>
<td>
<h:inputTextarea id="text" value="#{translator.text}" required="true" rows="5" cols="80" />
</td>
<td>
<h:outputText value="#{translator.translatedText}" />
</td>
</tr>
</table>
<div>
<h:commandButton id="button" value="Translate" action="#{translator.translate}"/>
</div>
</h:form>
The user can enter some text in the lefthand textarea, and hit the translate button to see the result to the right.
Finally, let's look at the ejb module,
webbeans-translator-ejb
.
In src/main/resources/META-INF
there is just an
empty web-beans.xml
, used to mark the archive as
containing Web Beans.
We've saved the most interesting bit to last, the code! The project has
two simple beans, SentenceParser
and
TextTranslator
and two enterprise beans,
TranslatorControllerBean
and
SentenceTranslator
. You should be getting quite
familiar with what a Web Bean looks like by now, so we'll just
highlight the most interesting bits here.
Both SentenceParser
and
TextTranslator
are dependent beans, and
TextTranslator
uses constructor initialization:
public class TextTranslator {
private SentenceParser sentenceParser;
private Translator sentenceTranslator;
@Initializer
TextTranslator(SentenceParser sentenceParser, Translator sentenceTranslator)
{
this.sentenceParser = sentenceParser;
this.sentenceTranslator = sentenceTranslator;
TextTranslator
is a stateless bean (with a local
business interface), where the magic happens - of course, we couldn't
develop a full translator, but we gave it a good go!
Finally, there is UI orientated controller, that collects the text from the user, and dispatches it to the translator. This is a request scoped, named, stateful session bean, which injects the translator.
@Stateful
@RequestScoped
@Named("translator")
public class TranslatorControllerBean implements TranslatorController
{
@Current TextTranslator translator;
The bean also has getters and setters for all the fields on the page.
As this is a stateful session bean, we have to have a remove method:
@Remove
public void remove()
{
}
The Web Beans manager will call the remove method for you when the bean is destroyed; in this case at the end of the request.
That concludes our short tour of the Web Beans RI examples. For more on the RI, or to help out, please visit http://www.seamframework.org/WebBeans/Development.
We need help in all areas - bug fixing, writing new features, writing examples and translating this reference guide.