JSF Introduction - JSF and HTML5 - page 27

If you click the "Go home" button and you leave the required input fields empty, you will face the validation error
messages as shown in Figure 1-11 :

Figure 1-11. Validation errors due to the absence of “immediate” to true

This is because the "Go home" command button makes a POST submit that triggers the JSF life cycle, and due to
the validations on the input fields, the "Go home" operation could not be completed.
The JSF framework provides the "immediate" attribute, which allows skipping the conversion and the validation
of the JSF life cycle. What the "immediate" attribute actually does is to allow the action event to be executed in the
“Apply Request Values” phase. Setting the immediate attribute to true as follows resolves this issue:

<h:form id="favForm">
...
<h:inputText id="favoriteFood"
value="#{favorite.food}"
required="true">
</h:inputText>
... <!-- other required fields -->
<h:commandButton value="Save my favorites" action="#{favorite.save}"/>
<h:commandButton value="Go home" action="index" immediate="true"/>
</h:form>

■ the <h:link> and <h:button> are new components that have been introduced since JSF 2.0; they can be
used to implement the GET navigation to target pages using the outcome attribute (you already saw an example of the
<h:link> in the firstApplication ). as a result of this, these new components can be used directly instead of the
command button and command link with the immediate attribute set to true for doing the navigation without executing
conversion and validation.

Note

Adding to the UICommand components, the immediate attribute can be applied to the EditableValueHolder
components (such as the input text). If the immediate attribute is set to true for an EditableValueHolder component,
the conversion and the validation of the EditableValueHolder components will be executed in the “Apply Request
Values” phase (before the “Process Validations” phase).