faces-config.xml: expression in to-view-id gets evaluated always

Question

I'm using JBoss AS / WildFly with JSF 2.2. This is an example of my faces-config.xml file. From outcome of my starting page (the menu page) I want to call the next one, to-view-id uses EL.

<navigation-rule>
    <from-view-id>/index.xhtml</from-view-id>
    <!-- Sales -->
    <navigation-case>
        <from-outcome>AUFTRAGSSUCHE</from-outcome>
        <to-view-id>#{salesOrders.start()}</to-view-id>
    </navigation-case>
    <navigation-case>
        <from-outcome>AUFTRAGSERFASSUNG</from-outcome>
        <to-view-id>#{salesOrderEntry.start()}</to-view-id>
    </navigation-case>
</navigation-rule>

Works, but problem is, that user chose AUFTRAGSERFASSUNG the EL for all cases before, here only AUFTRAGSSUCHE get evaluated. Although the from-outcome is different. In reality the list of navigation-cases is much longer. If user chose to start the last entry, all others before get evaluated. Means the beans get instantiated, ... Not a lightweight thing. So you can feel the difference, first menu entries start fast, last ones very slow.

Why are those EL expressions evaluated? Do I have a chance to switch this off? Any other hint how to improve this?

My first suggestion would be (since you use jsf 2.x) is to use implicit navigation. stackoverflow.com/questions/18037884/… — Kukeltje
Are you using Jboss AS or Wildfly? JBoss AS only supports JSF 2.1. — teacurran
I'm tried with WildFly 10 which is using JSF 2.2. But older versions show the same effect. — FrankL

teacurran teacurran · Accepted Answer · 2015-08-08T14:57:17

Reading the mojorra 2.2 source, it is clear that the to-view-id gets evaluated no matter the from-outcome as you observed. There is no way to configure it otherwise.

Why is the el-expression there in the first place? Are you doing some action and then returning the view id?

A better way to do it might be to use a view action:

<navigation-rule>
    <from-view-id>/index.xhtml</from-view-id>
    <!-- Sales -->
    <navigation-case>
        <from-outcome>AUFTRAGSSUCHE</from-outcome>
        <to-view-id>/sales-order/start.xhtml</to-view-id>
    </navigation-case>
</navigation-rule>

And then in /sales-order/start.xhtml do this:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
  <html xmlns="http://www.w3.org/1999/xhtml"
      xmlns:h=" "
      xmlns:f=" ">
    <f:metadata>
        <f:viewAction action="#{salesOrders.start}"/>
    </f:metadata>
    <h:head>
        <title>Sales Order Start< /title>
    </h:head>
    <h:body>
        <!-- Sales order page here -->
    </h:body>
</html>

You would just have salesOrder.start() return void

faces-config.xml: expression in to-view-id gets evaluated always

1 Answers