Datatable is not updated after adding records - jsf

Question

I have an init() function that returns a list of emails that will be displayed in a Primefaces datatable. And I have a commandButton that extract emails and persist them in the dataTable. These new records show up in the dataTable only if I log out and log in.
This is my init() function ( my managed Bean is annotated with #ManagedBean(name = "mailMB") and #SessionScoped) :
#PostConstruct
public void init() {
emails = new ArrayList();
idCustomer = (String) session.getAttribute("idCustomer");
System.out.println(idCustomer + " this is it");
cust = customerBusinessLocal.findById(idCustomer);
System.out.println(cust.getName());
datas = dataBusinessLocal.findByCustomer(cust);
System.out.println(datas.size());
for (Data d : datas) {
for (Email e : mailBusinessLocal.mailsByData(d)) {
emails.add(e);
}
}
public List<Email> getEmails() {
return emails;
}
In my page xhtml i've implemented the code below:
<h:form id="form">
<p:commandButton value="Extract" update="tableemails" id="ajax" widgetVar="extractButton"
action="#{mailMB.searchEmails()}"
icon="ui-icon-disk" styleClass="ui-priority-primary"
onstart="blockUIWidget1.block()"
oncomplete="blockUIWidget1.unblock()"/>
<pe:blockUI target="formulaire" widgetVar="blockUIWidget1">
<h:panelGrid columns="2">
<img src="../../pictures/animated-loading-bar.gif" width="264" height="34" alt="animated-loading-bar"/>
<h:outputText value="Please wait..." style="white-space: nowrap;"/>
</h:panelGrid>
</pe:blockUI>
<p:panel id="display" header="Emails" >
<p:dataTable id="tableemails" value="#{mailMB.emails}" var="item" rowsPerPageTemplate="5,10,15" paginatorTemplate="{CurrentPageReport} {FirstPageLink} {PreviousPageLink} {PageLinks} {NextPageLink} {LastPageLink} {RowsPerPageDropdown}"
paginator="true" rows="10" styleClass="case-table" emptyMessage="No records found with given criteria" paginatorPosition="bottom"
filteredValue="#{mailMB.filteredMails}" rowKey="#{item.id}"
selection="#{mailMB.selectedMail}" selectionMode="single" >
<p:ajax event="rowSelect" update=":form:display"/>
<p:column styleClass="blockable" filterStyle="width: 250px" filterBy="#{item.email} " sortBy="#{item.email}">
<f:facet name="header">
<h:outputText value="Email"/>
</f:facet>
<h:outputText value="#{item.email}"/>
</p:column>
</p:dataTable>
</p:panel>
</h:form>

Answer 1

it looks like you do not reload your List<Email> emails after persisting some new data. #PostConstract is executed once after your bean is created (sincce it's #SessionScoped it's created once per session), thats why you see changes only after another login. Add a method repopulateEmails() that would load data from database and run it after you add/remove something, just add it to your persist() method.
public void persist()
{
....
getEntityManager().persist(getInstance());
getEntityManager().flush();
emails = null;
......
}
public List<Email> getEmails(){
if(emails == null){
emails = repopulateEmails();
}
return emails;
}