| By Max Katz |
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| September 8, 2009 08:00 PM EDT |
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During my RichFaces session at JBoss World 2009, I showed three small examples of using Ajax with RichFaces 3.3, JSF 2, and RichFaces 4. I thougth it would be a good idea to show you the difference or more correct the similarities between the three. I will be blogging more about RichFaces 4 and JSF 2 so this is just a quick introduction.
I will show a small “Echo” application. There is one input field and as as you type, the input is echoed on the next line. On another line, the length of the string entered is counted. It looks like this:
RichFaces 3.3
<h:form>
<h:panelGrid columns="2">
<h:outputText value="Text:" />
<h:inputText value="#{echoBean.text}" >
<a4j:support event="onkeyup" action="#{echoBean.countAction}"
reRender="text, count"/>
</h:inputText>
<h:outputText value="Echo:" />
<h:outputText id="text" value="#{echoBean.text}" />
<h:outputText value="Count:" />
<h:outputText id="count" value="#{echoBean.count}" />
</h:panelGrid>
</h:form>
Managed bean:
public class EchoBean {
private String text; // getter and setter
private Integer count; // getter and setter
public void countAction() {
count = text.length();
}
...
}
Bean is registered in JSF configuration file (not shown).
JSF 2
<h:form>
<h:panelGrid columns="2">
<h:outputText value="Text:" />
<h:inputText value="#{echoBean.text}" >
<f:ajax event="keyup" execute="@form" render="text count"
listener="#{echoBean.countListener}"/>
</h:inputText>
<h:outputText value="Echo:" />
<h:outputText id="text" value="#{echoBean.text}" />
<h:outputText value="Count:" />
<h:outputText id="count" value="#{echoBean.count}" />
</h:panelGrid>
</h:form>
Managed bean looks slightly different as instead of an action (see example above) we use a special Ajax listener:
@ManagedBean(name="echoBean")
@RequestScoped
public class EchoBean {
private String text;
private Integer count;
public void countListener (AjaxBehaviorEvent event) {
count = text.length();
}
}
RichFaces 4.0
<h:form>
<h:panelGrid columns="2">
<h:outputText value="Text:" />
<h:inputText value="#{echoBean.text}" >
<a4j:ajax event="keyup" render="text,count"
listener="#{echoBean.countListener}"/>
</h:inputText>
<h:outputText value="Echo:" />
<h:outputText id="text" value="#{echoBean.text}" />
<h:outputText value="Count:" />
<h:outputText id="count" value="#{echoBean.count}" />
</h:panelGrid>
</h:form>
Managed bean is same as in JSF 2.
- Ajax features in JS2 are very similar to what’s been available in RichFaces for a couple of year. The JSF standard continues to evolve by assimilating the best ideas in the community into the standard. A perfect example is how the Ajax support in JSF 2.0 almost matches that of RichFaces.
- a4j:support has been replaced with a4j:ajax in RichFaces 4
- a4j:ajax has all the functionality of standard JSF 2 Ajax tag with many additional features to give you more flexibility and power available only in RichFaces.
- For example, features such as client queues, more control on deciding what to process and render, defining parts of a view to always render and much much more.
Max Katz is a Senior Systems Engineer at Exadel. He has been helping customers jump-start their RIA development as well as providing mentoring, consulting, and training. Max is a recognized subject matter expert in the JSF developer community. He has provided JSF/RichFaces training for the past four years, presented at many conferences, and written several published articles on JSF-related topics. Max also leads Exadel's RIA strategy and writes about RIA technologies in his blog, http://mkblog.exadel.com. He is an author of "Practical RichFaces" book (Apress). Max holds a BS in computer science from the University of California, Davis.
