[jbossseam-issues] [JBoss JIRA] Updated: (JBSEAM-3295) Major reentrancy problem with "Application Scope" components and injection/disinjection

[Denis Forveille (JIRA)]

     [ https://jira.jboss.org/jira/browse/JBSEAM-3295?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Denis Forveille updated JBSEAM-3295:
------------------------------------

    Attachment: BijectionInterceptor_Denis.java


Attached our non-optimized version of BijectionInterceptor
It could easily be optimized in many ways, including the usage of an AtomicInteger as you did...but the logic respects the logic of the initial BijectionInterceptor, ie injecting/disinjecting only on the first level of methdo calls

> Major reentrancy problem with "Application Scope" components and injection/disinjection
> ---------------------------------------------------------------------------------------
>
>                 Key: JBSEAM-3295
>                 URL: https://jira.jboss.org/jira/browse/JBSEAM-3295
>             Project: Seam
>          Issue Type: Bug
>          Components: Core
>    Affects Versions: 2.0.2.SP1
>         Environment: WebSphere v6.1.0.17 in POJO Mode
>            Reporter: Denis Forveille
>            Assignee: Shane Bryzak
>            Priority: Blocker
>             Fix For: 2.0.3.CR2, 2.1.0.BETA1
>
>         Attachments: BijectionInterceptor_Denis.java
>
>
> There is a major reentrancy problem with "Application Scope" components and injection/disinjection
> As in any component @In dependent object are injected/disinjected with  the BijectionInterceptor interceptor
> As there is one instance of BijectionInterceptor per Component (It seems), there is only one instance of BijectionInterceptor in the JVM for an Application Scope Component, instance shared by all threads
> With that in mind, take:
> - 2 running thread (T1, T2)
> - One application scope component (C1) with many at In attributes (All referecing Application Scope components too..)
> T1 enters method M1 of C1. BijectionInterceptor  inject @In depedencies of C1, and set the "reentrant" attribute of the instance of BijectionInterceptor attached to C1 to  "true"
> T2 enters method M1of C1. BijectionInterceptor does nothing as "reentrant"  is true
> T1 exits method M1 of C1. As this is thios thread (T1) that set "reentrant" initially, it performs the "disinjection" and set all the @In  attribues of C1 to null
> T2 then fails with NPE as all the @In attributes of C1 are set to null !!!!!
> Core of the org.jboss.seam.core.BijectionInterceptor class:
>    private boolean reentrant; //OK, since all Seam components are single-threaded
>    @AroundInvoke
>    public Object aroundInvoke(InvocationContext invocation) throws Exception{
>       if (reentrant) {
>          return invocation.proceed();
>       }
>       else {
>          reentrant = true;
>          try {
>             Component component = getComponent();
>             boolean enforceRequired = !component.isLifecycleMethod( invocation.getMethod() );
>             component.inject( invocation.getTarget(), enforceRequired );
>             Object result = invocation.proceed();            
>             component.outject( invocation.getTarget(), enforceRequired );
>             component.disinject( invocation.getTarget() );
>             return result;
>          }
>          finally {
>             reentrant = false;
>          }
>       }
>    }

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