Q: What is
the difference between JSP-EL and JSF-EL?
JSP-EL JSF-EL
In JSP-EL the value expressions are delimited by ${…}. In JSf-EL the value expressions are delimited by #{…}.
The ${…} delimiter denotes the immediate evaluation of the expressions, at the time that the application server processes the page. The #{…} delimiter denotes deferred evaluation. With deferred evaluation ,the application server retains the expression and evaluates it whenever a value is needed.
JSP-EL JSF-EL
In JSP-EL the value expressions are delimited by ${…}. In JSf-EL the value expressions are delimited by #{…}.
The ${…} delimiter denotes the immediate evaluation of the expressions, at the time that the application server processes the page. The #{…} delimiter denotes deferred evaluation. With deferred evaluation ,the application server retains the expression and evaluates it whenever a value is needed.
note:As of JSF 1.2
and JSP 2.1 ,the syntax of both expression languages
has been unified.
Q: What are
The main tags in JSF?
JSF application typically uses JSP pages to represent views. JSF provides useful special tags to enhance these views. Each tag gives rise to an associated component. JSF (Sun Implementation) provides 43 tags in two standard JSF tag libraries:
• JSF Core Tags Library.
• JSF Html Tags Library.
18. How do you declare the managed beans in the faces-config.xml file?
The bean instance is configured in the faces-config.xml file:
JSF application typically uses JSP pages to represent views. JSF provides useful special tags to enhance these views. Each tag gives rise to an associated component. JSF (Sun Implementation) provides 43 tags in two standard JSF tag libraries:
• JSF Core Tags Library.
• JSF Html Tags Library.
18. How do you declare the managed beans in the faces-config.xml file?
The bean instance is configured in the faces-config.xml file:
<managed-bean>
<managed-bean-name>login</managed-bean-name>
<managed-bean-class>com.developersBookJsf.loginBean</managed-bean-class>
<managed-bean-scope>request</managed-bean-scope>
</managed-bean>
This means: Construct
an object of the class com.developersBookJsf.loginBean,
give it the name login, and keep it alive for
the duration of the request.
Q: How to declare
the Message Bundle in JSF?
We can declare the message bundle in two ways:
(Let’s assume com.developersBookJsf.messages is the properties file)
1. The simplest way is to include the following elements in faces-config.xml file:
<application>We can declare the message bundle in two ways:
(Let’s assume com.developersBookJsf.messages is the properties file)
1. The simplest way is to include the following elements in faces-config.xml file:
<resource-bundle>
<base-name>com.developersBookJsf.messages</base-name>
<var>message</var>
</resource-bundle>
</application>
2. Alternatively, you can add the f:loadBundle element to each JSF page that needs access to the bundle:
<f:loadBundle baseName = “com.developersBookJsf.messages” var=”message”/>
Q: How to declare
the page navigation (navigation rules) in faces-config.xml
file ?
Navigation rules tells JSF implementation which page to send back to the browser after a form has been submitted. We can declare the page navigation as follows:
<naviagation-rule>Navigation rules tells JSF implementation which page to send back to the browser after a form has been submitted. We can declare the page navigation as follows:
<from-view-id>/index.jsp</from-view-id>
<navigation-case>
<from-outcome>login</from-outcome>
<to-view-id>/welcome.jsp</to-view-id>
</navigation-case>
</naviagation-rule>
This declaration states that the login action navigates to /welcome.jsp, if it occurred inside /index.jsp.
Q: What if
no navigation rule matches a given action?
If no navigation rule matches a given action, then the current page is redisplayed.
If no navigation rule matches a given action, then the current page is redisplayed.
Q: What are the JSF life-cycle phases?
The six phases of the JSF application lifecycle are as follows (note the event processing at each phase): 1. Restore view
2. Apply request values; process events
3. Process validations; process events
4. Update model values; process events
5. Invoke application; process events
6. Render response
Q: Explain briefly the life-cycle phases of JSF?
1. Restore View : A request comes through the FacesServlet controller. The controller examines the request and extracts the view ID, which is determined by the name of the JSP page.
2. Apply request values: The purpose of the apply request values phase is for each component to retrieve its current state. The components must first be retrieved or created from the FacesContext object, followed by their values.
3. Process validations: In this phase, each component will have its values validated against the application's validation rules.
4. Update model values: In this phase JSF updates the actual values of the server-side model ,by updating the properties of your backing beans.
5. Invoke application: In this phase the JSF controller invokes the application to handle Form submissions.
6. Render response: In this phase JSF displays the view with all of its components in their current state.
Q: What does it mean by render kit in JSF?
A render kit defines how component classes map to component tags that are appropriate for a particular client. The JavaServer Faces implementation includes a standard HTML render kit for rendering to an HTML client.
Q: Is it possible to have more than one Faces Configuration file?
We can have any number of config files. Just need to register in web.xml.
Assume that we want to use faces-config(1,2,and 3),to register more than one faces configuration file in JSF,just declare in the web.xml file
<param-name>javax.faces.CONFIG_FILES</param-name>
<param-value>
/WEB-INF/faces-config1.xml,
/WEB-INF/faces-config2.xml,
/WEB-INF/faces-config3.xml
</param-value>
</context-param>