<p:tabView id="tabView" var="category" value="#{showcaseBean.categories}">
<p:ajax event=”tabChange” listener=”#{showcaseBean.onChange}” />

<var name="showcaseBean" class="backing.ShowcaseBean"/>

public void onChange(TabChangeEvent event)
    {
        Tab activeTab = event.getTab();
      //тут я как то наверное должен сделать запрос в базу и получить категорию и список связанных с ней товаров
    }

ShoppingService shoppingService = new ShoppingService();
 shoppingService.getArticlesByCategory();

<transition on="tabChange">
			<evaluate expression="shoppingService.getArticlesByCategory(showcaseBean)" />
		</transition>

      <transition on="confirm" to="bookingConfirmed">
			<evaluate expression="bookingService.persistBooking(booking)" />
		</transition>
           где confirm - это из
             <р:commandButton action="confirm"/>

<h:form id="articlesForm">
          <p:tabView id="tabView" var="category" value="#{showcaseBean.categories}" onTabChange="tabChanged()">
           <p:ajax event="tabChange" listener="#{showcaseBean.onChange}" />
...
</p:tabView>

<p:remoteCommand name="tabChanged" action="switchTab"/>

    public void onChange(TabChangeEvent event)
    {
        chosenCategory = (Category)event.getData();
    }

<var name="showcaseBean" class="my.backing.ShowcaseBean"/>
    <view-state id="showcase" view="showcase.xhtml" >
       
     <transition on="switchTab">
         <evaluate expression="showcaseBean.fetchArticlesForChosenCategory(showcaseService)"/>
     </transition>

   </view-state>

<script type="text/javascript">
           window.onload = function ()
           {
               updateTabs();
           }
       </script>

<p:remoteCommand name="updateTabs" action="actionForMyFlowDefinitionFile"/>