[jboss-jira] [JBoss JIRA] Closed: (JBPM-992) ProcessClassLoader : cannot load resource from code deployed inside a process archive

[Tom Baeyens (JIRA)]

     [ http://jira.jboss.com/jira/browse/JBPM-992?page=all ]

Tom Baeyens closed JBPM-992.
----------------------------

    Resolution: Done

Loading process archive resources changed. Loading classes remained the same, but now if you load a resource with the process classloader, it will look into the /classes directory in the process archive. 

>From the docs:
"
Delegation classes are loaded with the process class loader of their respective process 
definition. The process class loader is a class loader that has the jBPM classloader as 
a parent. The process class loader adds all the classes of one particular process definition. 
You can add classes to a process definition by putting them in the /classes folder in the 
process archive. Note that this is only useful when you want to version the classes that 
you add to the process definition. If versioning is not necessary, it is much more efficient 
to make the classes available to the jBPM class loader.

If the resource name doesn't start with a slash, resources are also loaded from the /classes 
directory in the process archive. If you want to load resources outside of the classes 
directory, start with a double slash ( // ). For example to load resource 
data.xml wich is located next to the processdefinition.xml on the root of the process archive 
file, you can do clazz.getResource("//data.xml") or 
classLoader.getResourceAsStream("//data.xml") or any of those getResource* variants. 
"

Please USE this feature extensively !  I included it because i thought it was going to be a 15 minute 
job.  Let me tell you: testing this was not simple.  It took me almost a day to test this properly.
So use it as much as you can so that that time was not in vain :-)

> ProcessClassLoader : cannot load resource from code deployed inside a process archive
> -------------------------------------------------------------------------------------
>
>                 Key: JBPM-992
>                 URL: http://jira.jboss.com/jira/browse/JBPM-992
>             Project: JBoss jBPM
>          Issue Type: Bug
>          Components: Core Engine
>    Affects Versions: jBPM jPDL 3.2
>         Environment: enterprise JBPM : process archive deployed and serialized into database
>            Reporter: Adrian Dimulescu
>         Assigned To: Tom Baeyens
>             Fix For: jBPM jPDL 3.2.2
>
>         Attachments: jbpm-patch-classloading-resource.patch
>
>
> A Java class deployed with a process archive may need access to a class path resource deployed in the same process archive.
> A common example is an ActionHandler implementation that calls a remote EJB and needs a jndi.properties file containin remote appserver location. In order to load that it calls :
> this.getClass().getClassLoader().getResourceAsStream("jndi.properties")
> This call generates a java.lang.NullPointerException which I think justifies the classification of this issue as a bug.
> Looking inside the ProcessClassLoader class, I see that in order to load a class, a "classes/" prefix. Indeed, the "par" format wants that all compiled classes be locates underneath the "classes/" directory. The JBPM_BYTEARRAY.NAME_ field in the database table confirms this : the NAME_ of the jndi.properties resource is : "classes/jndi.properties".
> Still the ProcessClassLoader.getResourceAsStream method does not use the classes prefix. 
> The fix look thus simple, i.e. adding that prefix.
> Second problem :  if the resource is not found, a delegation should be made to the parent classloader.

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