examples/jsf-managedBean-and-ejb/README.adoc

:index-group: Misc
:jbake-type: page
:jbake-status: status=published
= JSF Application that uses managed-bean and ejb

This is a simple web-app showing how to use dependency injection in JSF
managed beans using TomEE.

It contains a Local Stateless session bean `CalculatorImpl` which adds
two numbers and returns the result. The application also contains a JSF
managed bean `CalculatorBean`, which uses the EJB to add two numbers and
display the results to the user. The EJB is injected in the managed bean
using `@EJB` annotation.

== A little note on the setup:

You could run this in the latest Apache TomEE
https://repository.apache.org/content/repositories/snapshots/org/apache/tomee/apache-tomee/[snapshot]

As for the libraries, myfaces-api and myfaces-impl are provided in
tomee/lib and hence they should not be a part of the war. In maven
terms, they would be with scope `provided'

Also note that we use servlet 2.5 declaration in web.xml

[source,xml]
----
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
version="2.5">
----

And we use 2.0 version of faces-config

The complete source code is provided below but let’s break down to look
at some smaller snippets and see how it works.

We’ll first declare the `FacesServlet` in the `web.xml`

[source,java]
----
  <servlet>
    <servlet-name>Faces Servlet</servlet-name>
    <servlet-class>jakarta.faces.webapp.FacesServlet</servlet-class>
    <load-on-startup>1</load-on-startup>
  </servlet>
----

`FacesServlet` acts as the master controller.

We’ll then create the `calculator.xhtml` file.

[source,java]
----
       <h:outputText value='Enter first number'/>
       <h:inputText value='#{calculatorBean.x}'/>
       <h:outputText value='Enter second number'/>
       <h:inputText value='#{calculatorBean.y}'/>
       <h:commandButton action="#{calculatorBean.add}" value="Add"/>
----

Notice how we’ve use the bean here. By default it is the simple class
name of the managed bean.

When a request comes in, the bean is instantiated and placed in the
appropriate scope. By default, the bean is placed in the request scope.

[source,java]
----
        <h:inputText value='#{calculatorBean.x}'/>
----

Here, getX() method of calculatorBean is invoked and the resulting value
is displayed. x being a Double, we rightly should see 0.0 displayed.

When you change the value and submit the form, these entered values are
bound using the setters in the bean and then the commandButton-action
method is invoked.

In this case, `CalculatorBean#add()` is invoked.

`Calculator#add()` delegates the work to the ejb, gets the result,
stores it and then instructs what view is to be rendered.

You’re right. The return value ``success'' is checked up in faces-config
navigation-rules and the respective page is rendered.

In our case, `result.xhtml` page is rendered.

The request scoped `calculatorBean` is available here, and we use EL to
display the values.

== Source

== Calculator

[source,java]
----
package org.superbiz.jsf;

import jakarta.ejb.Local;

@Local
public interface Calculator {
    public double add(double x, double y);
}
----

== CalculatorBean

[source,java]
----
package org.superbiz.jsf;

import jakarta.ejb.EJB;
import jakarta.faces.bean.ManagedBean;

@ManagedBean
public class CalculatorBean {
    @EJB
    Calculator calculator;
    private double x;
    private double y;
    private double result;

    public double getX() {
        return x;
    }

    public void setX(double x) {
        this.x = x;
    }

    public double getY() {
        return y;
    }

    public void setY(double y) {
        this.y = y;
    }

    public double getResult() {
        return result;
    }

    public void setResult(double result) {
        this.result = result;
    }

    public String add() {
        result = calculator.add(x, y);
        return "success";
    }
}
----

== CalculatorImpl

[source,java]
----
package org.superbiz.jsf;

import jakarta.ejb.Stateless;

@Stateless
public class CalculatorImpl implements Calculator {

    public double add(double x, double y) {
        return x + y;
    }
}
----

== web.xml

[source,xml]
----
<?xml version="1.0"?>

    <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns="http://java.sun.com/xml/ns/javaee"
    xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
    http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
    version="2.5">

    <description>MyProject web.xml</description>

    <!-- Faces Servlet -->
    <servlet>
        <servlet-name>Faces Servlet</servlet-name>
        <servlet-class>jakarta.faces.webapp.FacesServlet</servlet-class>
        <load-on-startup>1</load-on-startup>
    </servlet>

    <!-- Faces Servlet Mapping -->
    <servlet-mapping>
       <servlet-name>Faces Servlet</servlet-name>
        <url-pattern>*.jsf</url-pattern>
    </servlet-mapping>

    <!-- Welcome files -->
    <welcome-file-list>
       <welcome-file>index.jsp</welcome-file>
       <welcome-file>index.html</welcome-file>
    </welcome-file-list>
    </web-app>
----

== Calculator.xhtml

[source,xml]
----
<?xml version="1.0" encoding="UTF-8"?>
<!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:f="http://java.sun.com/jsf/core"
xmlns:h="http://java.sun.com/jsf/html">


<h:body bgcolor="white">
    <f:view>
        <h:form>
            <h:panelGrid columns="2">
            <h:outputText value='Enter first number'/>
           <h:inputText value='#{calculatorBean.x}'/>
            <h:outputText value='Enter second number'/>
            <h:inputText value='#{calculatorBean.y}'/>
           <h:commandButton action="#{calculatorBean.add}" value="Add"/>
            </h:panelGrid>
        </h:form>
   </f:view>
</h:body>
</html>
----

== Result.xhtml

[source,xml]
----
<?xml version="1.0" encoding="UTF-8"?>
<!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:f="http://java.sun.com/jsf/core"
xmlns:h="http://java.sun.com/jsf/html">

<h:body>
    <f:view>
        <h:form id="mainForm">
            <h2><h:outputText value="Result of adding #{calculatorBean.x} and #{calculatorBean.y} is #{calculatorBean.result }"/></h2>
            <h:commandLink action="back">
            <h:outputText value="Home"/>
            </h:commandLink>
        </h:form>
    </f:view>
</h:body>
</html>
----

== faces-config.xml

[source,xml]
----
<?xml version="1.0"?>
<faces-config 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_2_0.xsd"
version="2.0">

<navigation-rule>
    <from-view-id>/calculator.xhtml</from-view-id>
    <navigation-case>
        <from-outcome>success</from-outcome>
        <to-view-id>/result.xhtml</to-view-id>
    </navigation-case>
</navigation-rule>

<navigation-rule>
    <from-view-id>/result.xhtml</from-view-id>
    <navigation-case>
        <from-outcome>back</from-outcome>
        <to-view-id>/calculator.xhtml</to-view-id>
    </navigation-case>
</navigation-rule>
</faces-config>
----