HTML and CSS Reference
In-Depth Information
Rule-Based Navigation
In rule-based navigation, the navigation rules are defined in the Faces configuration file (
faces-config.xml
).
Rule-based navigation consists of a set of navigation rules. Every navigation rule can have one or more navigation case(s).
Listing 2-28 shows a rule-based navigation example.
Listing 2-28.
Rule-Based Navigation Example 1
<faces-config ...>
<navigation-rule>
<from-view-id>/index.xhtml</from-view-id>
<navigation-case>
<from-action>#{exampleBean.doAction}</from-action>
<from-outcome>success</from-outcome>
<to-view-id>/welcome.xhtml</to-view-id>
</navigation-case>
<navigation-case>
<from-action>#{exampleBean.doAction}</from-action>
<from-outcome>fail</from-outcome>
<to-view-id>/invalid.xhtml</to-view-id>
</navigation-case>
</navigation-rule>
</faces-config>
As shown in the example, the navigation rule can contain the following elements:
•
<from-view-id>
(Optional), which represents the view from which the navigation starts.
•
<navigation-case>
, which can be from 1 to N inside the navigation rule.
The navigation case can contain the following elements:
<from-action>
(Optional), which holds an EL expression which refers to an action method
that returns a String (outcome).
•
<from-outcome>
, which represents a String literal outcome. In the presence of the
<from-
action>
element, the
<from-outcome>
value is compared with the
<from-action>
returned
outcome, and if the two values are matched then the navigation proceeds to the
<to-view-
id>
. If the
<from-action>
element is not present then the
<from-outcome>
is compared with
the
action
attribute of the action source components, and if the two values are matched
then the navigation proceeds to the
<to-view-id>
(will be illustrated in the next navigation
example).
•
<to-view-id>
, which represents the target view.
Looking back in the example, starting from the
index.xhtml
page, the first navigation case fires when the
#{exampleBean.doAction}
action method is executed and returned the
"success"
outcome; in this case, the page will
be forwarded to the
welcome.xhtml
page. The other navigation case fires when the
#{exampleBean.doAction}
action
method is executed and returns the
"fail"
outcome; in this case, the page will be forwarded to the
invalid.xhtml
page. Listing 2-29 shows the important part of the
ExampleBean
managed bean.
•
