CODEWITHSUNDEEP
validationjsf
amphibient
amphibient

Reputation: 31212

How to make a form field conditionally required in JSF?

Suppose I have an h:form with three fields and two submit buttons. The submit buttons are, say, Display Report and Generate Data. For the simplicity, I would prefer to have only one and not multiple forms. When Display Report, the values from the three fields are required as criteria for the report presentation. So I marked them as required="true" but that disables the execution of Generate Data, which does not need those three fields.

Is there a way to make JSF form fields conditionally required without much custom coding, something like requiredIf=#{condition}?

Upvotes: 1

Views: 8335

Answers (1)

Dawid Pytel
Dawid Pytel

Reputation: 2810

If Generate Data action does not require any conversion or validation of form data then set the attribute immediate to true for this button:

<h:commandButton action="#{someBean.generateData}" value="Generate Data" immediate="true"/>

This way action generateData is invoked before any conversion or validation takes place and form data is not validated at all.

If Generate data needs data from the form then you can use trick described by BalusC here: JSF 2.0 validation in actionListener or action method

In short, as @Jean-François suggested you can use EL expressions as value of required attribute. The EL expression should evaluate to true only when user pressed Display Report button. This could be done using the following expression: #{not empty param['<fullIdOfTheDisplayReportButton>']}. This expression checks whether id of the button belongs to parameters, which means that given button was used to submit the form.

Full example:

<h:form id="formId">
    <p>
        Required only for Display Report: <h:inputText id="reqForDR" required="#{not empty param['formId:displayReportButton']}" />
    </p>
    <p>
        Required for Display Report and Generate Data: <h:inputText id="reqForDRGD" required="true"/>
    </p>
    <h:commandButton id="displayReportButton" action="#{someBean.displayReport}" value="Display Report"/>
    <h:commandButton id="generateDataButton" action="#{someBean.generateData}" value="Generate Data"/>
</h:form>

Upvotes: 5

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