How to retrieve a value from XHTML in my bean using <p:ajax> on primefaces?

Question

2.8 and Primefaces 6.0 And i want to retrieve the value of a date from my xhtml to make specific treatments Before submitting my form.

But the value of the date is always null in the bean Before submitting.

Here is my XHTML

                            <p:outputLabel for="dateDebut" value="Date Debut"/>
                        <p:calendar id="dateDebut" value="#{etpBean.dateDebut}" required="true">
                            <p:ajax listener="#{etpBean.listenerDateDebut}" event="change"/>
                        </p:calendar>

And here is my function in my bean

public Date listenerDateDebut(){
    return dateDebut;
}

Answer 1

From the PrimeFaces 6 documentation :

Ajax Behavior Events

Calendar provides a dateSelect ajax behavior event to execute an instant ajax selection whenever a date is selected. If you define a method as a listener, it will be invoked by passing an org.primefaces.event.SelectEvent instance.

 <p:calendar value="#{calendarBean.date}"> <p:ajax event="dateSelect" listener="#{bean.handleDateSelect}" update="msg" /> </p:calendar> <p:messages id="msg" /> 

 public void handleDateSelect(SelectEvent event) { Date date = (Date) event.getObject(); //Add facesmessage }