Click here to close now.

Welcome!

Java Authors: Pat Romanski, Elizabeth White, Liz McMillan, Asad Ali, Michael Kanasoot

Related Topics: Java, AJAX & REA

Java: Article

New Features in JavaServer Faces 2.0

Developing server-side user interfaces (UI) for Java EE applications

JavaServer Faces (JSF) technology is used for developing server-side user interfaces (UI) for Java EE applications. JSF 2.0 architecture has introduced several new features, most of which we shall discuss in this article. The salient new features in JSF 2.0 are State Saving, Facelets, Navigation, Validations, Scopes, AJAX, Resource Handling, Composite Components, View Params, Client Behaviors, Event Handling, and Exception Handling.

State Saving
In JSF 1.2 the full component tree is saved/restored. Attributes are also stored and restored. Saving and restoring the full state has performance and memory issues as the complete state has to be saved and restored and the size of the state saved could be large. In JSF 1.2 each UIComponent saves/restores its own state in the component hierarchy using saveState and resoreState methods in StateHolder. If state saving were to be optimized, it would have to be added to each component class in the hierarchy.

JSF 2.0 has introduced partial state saving in which the initial state of the component tree is marked and only the delta state changes due to modifications are saved, which makes the size of the state saved small. Re-executing the view and subsequently updating with the saved delta state change restores the component tree. Instead of implementing the StateHolder interface, components in JSF 2.0 implement the PartialStateHolder interface, which provides the partial state feature. PartialStateHolder provides methods shown in Table 1.

Table 1

To make it easier for UIComponents to implement PartialSatetHolder the StateHelper, which is a Map-like interface with methods such as add, eval, get, put, remove, is provided to store a component's state such as attributes and listeners. Partial state saving makes the size of the state saved about four times smaller. As the state is restored by re-executing the view, restoring of the component tree could take more time than in JSF 1.2.

By default, JSF 2.0 uses partial state saving. The javax.faces.PARTIAL_STATE_SAVING context-param is provided turn off/on partial state saving. The partial state saving param may be changed using the PARTIAL_STATE_SAVING_PARAM_NAME param.

To implement state saving, JSF 2.0 has introduced tree visiting. In JSF 1.2 only one component could be invoked in a single tree traversal using the UIComponent.invokeOnComponent() method. If multiple components are required to be invoked as in an AJAX request or state saving, multiple tree traversals have to applied. With the tree visiting, multiple components may be invoked in a single tree traversal. Tree visiting is implemented using the visitTree(VisitContext context,VisitCallback callback) method. VisitContext is a context object that holds state for component tree visit. VisitCallback is an interface to visit a specified UIComponent in tree visit.

Facelets
JSF 1.2 used the JSP view technology. JSF 2.0 uses the Facelets view definition language (VDL) as the default view rendering technology. Facelets is an extension to JavaServer Faces (JSF) and uses XHTML syntax to define a JSF page. Facelets are XHTML pages and by default use the .xhtml extension. The default Facelets suffix is specified by the DEFAULT_FACELETS_SUFFIX context parameter. The Facelets view handler in JSF 1.2 had to be specified in faces-config.xml with the following configuration:

<application>|
<view-handler>com.sun.facelets.FaceletViewHandler</view-handler>
</application>
</faces-config>

In JSF 2.0 a view handler is not configured and the default view handler javax.faces.application.ViewHandler is used. The default faces-config.xml for Facelets in JSF 2.0 is an empty file. The default value of the DEFAULT_FACELETS_SUFFIX constant in the ViewHandler view handler is .xhtml. Other Facelets view mappings(view pages to be interpreted as Facelets) may be specified using the javax.faces.FACELETS_VIEW_MAPPINGS context parameter:

<context-param>
<param-name>javax.faces.FACELETS_VIEW_MAPPINGS</param-name>
<param-value>*.jsf;*.jspx</param-value>
</context-param>

Navigation
Navigation in JSF 1.2 is configured using navigation rules based on outcomes from a view id in faces-config.xml. For example, to navigate to output.jsp if the outcome from input.jsp is "success" and to navigate to error.jsp if the outcome is "error", specify the following navigation rule in faces-config.xml:

<navigation-rule>
<from-view-id>/input.jsp</from-view-id>
<navigation-case>
<from-outcome>success</from-outcome>
<to-view-id>/output.jsp</to-view-id>
</navigation-case>
<navigation-case>
<from-outcome>error</from-outcome>
<to-view-id>/error.jsp</to-view-id>
</navigation-case>
</navigation-rule>

JSF 2.0 has simplified navigation with the introduction of implicit navigation with which the navigation is based on the outcome. Implicitly the JSF application navigates to a view id with the same name as the outcome. For example, if the outcome is "output", the navigation handler navigates to output.xhtml, if provided. JSF 2.0 has also introduced conditional navigation with which the navigation handler navigates to a view id based on a condition EL expression specified in faces-config.xml. JSF 2.0 has also introduced the ConfigurableNavigationHandler class for configuring navigation programmatically. Preemptive navigation is another new feature used to determine the destination URL based on outcome. The new components h:button and h:link support preemptive navigation.

Validation
Validation in JSF 1.2 is implemented using built-in validators f:validateDoubleRange (for a double value with an optional range), f:validateLongRange(a long value with an optional range), and f:validateLength (a String with a minimum and maximum number of characters). JSF 1.2 also supports custom validators with the f:validator tag and the javax.faces.validator.Validator interface. JSF 1.2 did not have built-in provisions for empty field validation and validation with regular expressions.

JSF 2.0 has introduced validation of empty fields, which is also available for custom validators. Three new built-in validators have been added: f:validateRegex for regular expressions, f:validateRequired for required field, and f:validateBean for Bean validation, which is another new feature. Bean validation is implemented in conjunction with validation constrain annotations, which are defined in the javax.validation.constraints package. Validation constraint annotations annotate managed bean properties. For example the @Size annotation constrains size, and the @Pattern annotation requires conformance with a regular expression. Bean validation is supported with custom validators also.

Scopes and Configuration
As mentioned earlier the faces-config.xml in JSF 2.0 is an empty file. JSF 1.2 faces-config.xml has configuration for managed beans, managed bean properties, scopes, validators, converters, and renderers. JSF 2.0 has introduced annotations-based configuration for managed beans, managed bean properties, scopes, validators, converters, and renderers. New scopes: view, flash, and custom have been added for finer-grained scopes. JSF 2.0 has added a new configuration project stage that indicates the state of a project.

AJAX
JSF 1.2 did not provide built-in support for AJAX, and an AJAX framework such as Ajax4jsf had to be used. Or AJAX had to be implemented with the XMLHttpRequest object without any framework. JSF 2.0 has added support for AJAX with the f:ajax tag, which includes support for partial page rendering and grouped components. AJAX support may also be added using the AJAX JSF library.

Resource Handling
Resources are files required by a JSF application such as CSS, JavaScript, and images. JSF 2.0 has added a ResourceHandler API that is based on path-based packaging conventions for serving resources. JSF 2.0 has also added new tags for resource handling; h:head, h:body, h:outputScript, and h:ouputStylesheet. Some of the other new resource handling features are relocating resources and ordering of multiple faces-config.xml application configuration resources.

Composite Components
JSF 2.0 has introduced a Composite Components tag library for creating composite components. A Composite component is a composite (collection) of other UI components. A composite component consists of a library, which makes use of the new resource handling feature, a definition page, and a using page, which are based on Facelets. A definition page defines a composite component and a using page makes use of a composite component.

View Params
JSF 1.2 includes support for sending parameters only in a POST request. View parameters add the provision to send request parameters in a GET request. View parameters are configured in the f:metadata tag using the f:viewParam tags. View params are EditableValueHolder components and may configured with validators and converters just as other EditableValueHolder components such as h:inputText. View parameters also support component system events using the f:event tag. Preemptive navigation, which was mentioned in the Navigation section, and bookmarking is made feasible with view params. View params may also be used with Faces redirects.

Client Behaviors
Behaviors are objects attached to components to provide additional functionality. Client behaviors are an implementation of behaviors with which scripts may be attached with components to be run from client-side events. A Facelet taglib is required for a client behavior. Client behaviors are added to a Facelets page using tags from the Facelets taglib.

Event Handling and Exception Handling
JSF 2.0 has introduced a new type of events called system events. System events are of two types: application scoped system events and component system events. System events are similar to, but with more precise granularity, to phase events. For event handling in an AJAX request the f:ajax tag includes a onevent attribute to register a callback Java Script function.

ExceptionHandler is a new class to handle unexpected exceptions. The f:ajax tag includes a onerror attribute for error handling callback function.

More Stories By Deepak Vohra

Deepak Vohra is a Sun Certified Java 1.4 Programmer and a Web developer.

Comments (0)

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


@ThingsExpo Stories
SYS-CON Events announced today that Solgenia will exhibit at SYS-CON's 16th International Cloud Expo®, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY, and the 17th International Cloud Expo®, which will take place on November 3–5, 2015, at the Santa Clara Convention Center in Santa Clara, CA. Solgenia is the global market leader in Cloud Collaboration and Cloud Infrastructure software solutions. Designed to “Bridge the Gap” between Personal and Professional Social, Mobile and Cloud user experiences, our solutions help large and medium-sized organizations dr...
SYS-CON Events announced today that Liaison Technologies, a leading provider of data management and integration cloud services and solutions, has been named "Silver Sponsor" of SYS-CON's 16th International Cloud Expo®, which will take place on June 9-11, 2015, at the Javits Center in New York, NY. Liaison Technologies is a recognized market leader in providing cloud-enabled data integration and data management solutions to break down complex information barriers, enabling enterprises to make smarter decisions, faster.
The WebRTC Summit 2014 New York, to be held June 9-11, 2015, at the Javits Center in New York, NY, announces that its Call for Papers is open. Topics include all aspects of improving IT delivery by eliminating waste through automated business models leveraging cloud technologies. WebRTC Summit is co-located with 16th International Cloud Expo, @ThingsExpo, Big Data Expo, and DevOps Summit.
@ThingsExpo has been named the Top 5 Most Influential M2M Brand by Onalytica in the ‘Machine to Machine: Top 100 Influencers and Brands.' Onalytica analyzed the online debate on M2M by looking at over 85,000 tweets to provide the most influential individuals and brands that drive the discussion. According to Onalytica the "analysis showed a very engaged community with a lot of interactive tweets. The M2M discussion seems to be more fragmented and driven by some of the major brands present in the M2M space. This really allows some room for influential individuals to create more high value inter...
After making a doctor’s appointment via your mobile device, you receive a calendar invite. The day of your appointment, you get a reminder with the doctor’s location and contact information. As you enter the doctor’s exam room, the medical team is equipped with the latest tablet containing your medical history – he or she makes real time updates to your medical file. At the end of your visit, you receive an electronic prescription to your preferred pharmacy and can schedule your next appointment.
The world's leading Cloud event, Cloud Expo has launched Microservices Journal on the SYS-CON.com portal, featuring over 19,000 original articles, news stories, features, and blog entries. DevOps Journal is focused on this critical enterprise IT topic in the world of cloud computing. Microservices Journal offers top articles, news stories, and blog posts from the world's well-known experts and guarantees better exposure for its authors than any other publication. Follow new article posts on Twitter at @MicroservicesE
The list of ‘new paradigm’ technologies that now surrounds us appears to be at an all time high. From cloud computing and Big Data analytics to Bring Your Own Device (BYOD) and the Internet of Things (IoT), today we have to deal with what the industry likes to call ‘paradigm shifts’ at every level of IT. This is disruption; of course, we understand that – change is almost always disruptive.
SYS-CON Events announced today the IoT Bootcamp – Jumpstart Your IoT Strategy, being held June 9–10, 2015, in conjunction with 16th Cloud Expo and Internet of @ThingsExpo at the Javits Center in New York City. This is your chance to jumpstart your IoT strategy. Combined with real-world scenarios and use cases, the IoT Bootcamp is not just based on presentations but includes hands-on demos and walkthroughs. We will introduce you to a variety of Do-It-Yourself IoT platforms including Arduino, Raspberry Pi, BeagleBone, Spark and Intel Edison. You will also get an overview of cloud technologies s...
SYS-CON Events announced today that SafeLogic has been named “Bag Sponsor” of SYS-CON's 16th International Cloud Expo® New York, which will take place June 9-11, 2015, at the Javits Center in New York City, NY. SafeLogic provides security products for applications in mobile and server/appliance environments. SafeLogic’s flagship product CryptoComply is a FIPS 140-2 validated cryptographic engine designed to secure data on servers, workstations, appliances, mobile devices, and in the Cloud.
Wearable technology was dominant at this year’s International Consumer Electronics Show (CES) , and MWC was no exception to this trend. New versions of favorites, such as the Samsung Gear (three new products were released: the Gear 2, the Gear 2 Neo and the Gear Fit), shared the limelight with new wearables like Pebble Time Steel (the new premium version of the company’s previously released smartwatch) and the LG Watch Urbane. The most dramatic difference at MWC was an emphasis on presenting wearables as fashion accessories and moving away from the original clunky technology associated with t...
SOA Software has changed its name to Akana. With roots in Web Services and SOA Governance, Akana has established itself as a leader in API Management and is expanding into cloud integration as an alternative to the traditional heavyweight enterprise service bus (ESB). The company recently announced that it achieved more than 90% year-over-year growth. As Akana, the company now addresses the evolution and diversification of SOA, unifying security, management, and DevOps across SOA, APIs, microservices, and more.
GENBAND has announced that SageNet is leveraging the Nuvia platform to deliver Unified Communications as a Service (UCaaS) to its large base of retail and enterprise customers. Nuvia’s cloud-based solution provides SageNet’s customers with a full suite of business communications and collaboration tools. Two large national SageNet retail customers have recently signed up to deploy the Nuvia platform and the company will continue to sell the service to new and existing customers. Nuvia’s capabilities include HD voice, video, multimedia messaging, mobility, conferencing, Web collaboration, deskt...
SYS-CON Media announced today that @WebRTCSummit Blog, the largest WebRTC resource in the world, has been launched. @WebRTCSummit Blog offers top articles, news stories, and blog posts from the world's well-known experts and guarantees better exposure for its authors than any other publication. @WebRTCSummit Blog can be bookmarked ▸ Here @WebRTCSummit conference site can be bookmarked ▸ Here
SYS-CON Events announced today that Cisco, the worldwide leader in IT that transforms how people connect, communicate and collaborate, has been named “Gold Sponsor” of SYS-CON's 16th International Cloud Expo®, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. Cisco makes amazing things happen by connecting the unconnected. Cisco has shaped the future of the Internet by becoming the worldwide leader in transforming how people connect, communicate and collaborate. Cisco and our partners are building the platform for the Internet of Everything by connecting the...
Temasys has announced senior management additions to its team. Joining are David Holloway as Vice President of Commercial and Nadine Yap as Vice President of Product. Over the past 12 months Temasys has doubled in size as it adds new customers and expands the development of its Skylink platform. Skylink leads the charge to move WebRTC, traditionally seen as a desktop, browser based technology, to become a ubiquitous web communications technology on web and mobile, as well as Internet of Things compatible devices.
SYS-CON Events announced today that robomq.io will exhibit at SYS-CON's @ThingsExpo, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. robomq.io is an interoperable and composable platform that connects any device to any application. It helps systems integrators and the solution providers build new and innovative products and service for industries requiring monitoring or intelligence from devices and sensors.
Docker is an excellent platform for organizations interested in running microservices. It offers portability and consistency between development and production environments, quick provisioning times, and a simple way to isolate services. In his session at DevOps Summit at 16th Cloud Expo, Shannon Williams, co-founder of Rancher Labs, will walk through these and other benefits of using Docker to run microservices, and provide an overview of RancherOS, a minimalist distribution of Linux designed expressly to run Docker. He will also discuss Rancher, an orchestration and service discovery platf...
SYS-CON Events announced today that Akana, formerly SOA Software, has been named “Bronze Sponsor” of SYS-CON's 16th International Cloud Expo® New York, which will take place June 9-11, 2015, at the Javits Center in New York City, NY. Akana’s comprehensive suite of API Management, API Security, Integrated SOA Governance, and Cloud Integration solutions helps businesses accelerate digital transformation by securely extending their reach across multiple channels – mobile, cloud and Internet of Things. Akana enables enterprises to share data as APIs, connect and integrate applications, drive part...
SYS-CON Events announced today that Vitria Technology, Inc. will exhibit at SYS-CON’s @ThingsExpo, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. Vitria will showcase the company’s new IoT Analytics Platform through live demonstrations at booth #330. Vitria’s IoT Analytics Platform, fully integrated and powered by an operational intelligence engine, enables customers to rapidly build and operationalize advanced analytics to deliver timely business outcomes for use cases across the industrial, enterprise, and consumer segments.
Cloud is not a commodity. And no matter what you call it, computing doesn’t come out of the sky. It comes from physical hardware inside brick and mortar facilities connected by hundreds of miles of networking cable. And no two clouds are built the same way. SoftLayer gives you the highest performing cloud infrastructure available. One platform that takes data centers around the world that are full of the widest range of cloud computing options, and then integrates and automates everything. Join SoftLayer on June 9 at 16th Cloud Expo to learn about IBM Cloud's SoftLayer platform, explore se...