[jbossseam-issues] [JBoss JIRA] Commented: (JBSEAM-1023) Looking up a filtered SMPC in non-faces servlet throws NPE

[Christian Bauer (JIRA)]

    [ http://jira.jboss.com/jira/browse/JBSEAM-1023?page=comments#action_12356483 ] 
            
Christian Bauer commented on JBSEAM-1023:
-----------------------------------------

This is apparently related to the fact that #{currentAccessLevel} is supposed to resolve against a @Factory method:

    /**
     * Assigns the context variable 'currentAccessLevel' when no user is logged in.
     * @return Integer Guest access level.
     */
    @Factory(value = "currentAccessLevel", scope = ScopeType.SESSION, autoCreate = true)
    public Integer getGuestAccessLevel() {
        return ((Role)Component.getInstance("guestRole")).getAccessLevel();
    }

If I trigger this factory method before I obtain the entityManager, it works:

// Trigger the factory
org.jboss.seam.Component.getInstance("currentAccessLevel")
EntityManager em = ((EntityManager)org.jboss.seam.Component.getInstance("entityManager")); 
em.joinTransaction(); 

file = (!"".equals(id)) ? em.find(File.class, Long.parseLong(id)) : null; 
...


> Looking up a filtered SMPC in non-faces servlet throws NPE
> ----------------------------------------------------------
>
>                 Key: JBSEAM-1023
>                 URL: http://jira.jboss.com/jira/browse/JBSEAM-1023
>             Project: JBoss Seam
>          Issue Type: Bug
>          Components: Core
>            Reporter: Christian Bauer
>         Assigned To: Gavin King
>            Priority: Minor
>             Fix For: 1.2.1.GA
>
>
> My servlet does:
>                 EntityManager em = ((EntityManager)org.jboss.seam.Component.getInstance("entityManager"));
>                 em.joinTransaction();
>                 file = (!"".equals(id)) ? em.find(File.class, Long.parseLong(id)) : null;
> This worked OK, but after I enabled this filter:
>     <core:filter name="accessLevelFilter">
>         <core:name>accessLevelFilter</core:name>
>         <core:parameters>
>             <key>currentAccessLevel</key>
>             <value>#{currentAccessLevel}</value>
>         </core:parameters>
>     </core:filter>
>     <core:managed-persistence-context name="entityManager"
>                                       auto-create="true"
>                                       entity-manager-factory="#{wikiEntityManagerFactory}">
>         <core:filters><value>#{accessLevelFilter}</value></core:filters>
>     </core:managed-persistence-context>
> It fails with:
> Caused by: java.lang.NullPointerException: facesContext
>         at org.apache.myfaces.el.ValueBindingImpl.getValue(ValueBindingImpl.java:379)
>         at org.jboss.seam.core.Expressions$1.getValue(Expressions.java:57)
>         at org.jboss.seam.persistence.HibernatePersistenceProvider.enableFilter(HibernatePersistenceProvider.java:60)
>         at org.jboss.seam.core.ManagedPersistenceContext.initEntityManager(ManagedPersistenceContext.java:85)
>         at org.jboss.seam.core.ManagedPersistenceContext.getEntityManager(ManagedPersistenceContext.java:105)
>         at sun.reflect.GeneratedMethodAccessor1775.invoke(Unknown Source)
>         at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
>         at java.lang.reflect.Method.invoke(Method.java:585)
>         at org.jboss.seam.util.Reflections.invoke(Reflections.java:18)
>         at org.jboss.seam.util.Reflections.invokeAndWrap(Reflections.java:121)
>         at org.jboss.seam.Component.callComponentMethod(Component.java:1834)
>         at org.jboss.seam.Component.unwrap(Component.java:1860)
>         at org.jboss.seam.Component.getInstance(Component.java:1657)
>         at org.jboss.seam.Component.getInstance(Component.java:1610)
>         at org.jboss.seam.Component.getInstance(Component.java:1604)
>         at org.jboss.seam.wiki.core.ui.FileServlet.doGet(FileServlet.java:70)
> The expression "#{currentAccessLevel}" can either be resolved to a variable in the SESSION context or to a factory method on one of my components.

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