Validators

The JSF core framework provides a number of basic validators that can be used to validate the entered values in an input form.

• validateDoubleRange

• validateLength

• validateLongRange

• validateRegex

• validateRequired

Example code fragment from an input form:

<p:inputText value="#{data.zipCode}" id="ZipCode" required="true">
    <f:convertNumber integerOnly="true" groupingUsed="false"/>
    <f:validateLength minimum="4" maximum="5"/>
</p:inputText>

Client Side Validation

In some cases it makes sense to perform the validation of the entered values before they are sent to the server (e.g. in an Offline Dialogs). For this reason, Primefaces provides a client side validation framework. Client side validation is added as addition to the JSF validators. Thus, it can give instant feedback - even while typing - to the user. Since the JSF validators (see above) remain still active, the data is also validated on server side after the form has passed client side validation and is submitted.

Example code fragment from an input form:

<p:inputText value="#{data.zipCode}" id="ZipCode" required="true">
    <f:convertNumber integerOnly="true" groupingUsed="false"/>
    <f:validateLength minimum="4" maximum="5"/>
    <p:clientValidator event="keyup" />
    <p:clientValidator event="blur" />
</p:inputText>
<p:message for="ZipCode" display="text" showDetail="true" />

<p:commandButton actionListener="#{logic.close}" value="Proceed" validateClient="true" icon="ui-icon-check"  />

Tip

It’s useful to add the client validators to the desired input field and also to trigger client side validation on the submit button. This way you make sure, that client side validation is performed during field modification, but also if the user tries to submit the from without any modification.

In order to provide a good instant feedback, a message element dedicated to the input field might be quite helpful.