[rules-users] Null pointer exception when using global in rdrl 6.0.1.F

[Wolfgang Laun]

On 28/01/2014, SrjTx <clickthex at yahoo.com> wrote:
> Thanks for the reply.
> I have read that section of the docs a multiple times.
>
> Unfortunately, I do not have a handle to the ksession to call setGlobal on.
>
> My knowledge session is created/owned by KIE-WB/Switchyard and we are
> looking for an API so that I can get a handle to something on which I can
> call setGlobal.

I've had a quick look at
   https://docs.jboss.org/author/display/SWITCHYARD/Knowledge+Services
and it seems to me that you need to define

<operations>
    <operation ...>
        <globals>
            <global from="" to=""/>
        </globals>
</...></...>

I suspect that "from" should be some Java expression returning the
global object and "to" the global's DRL name, perhaps from the
SwitchYard Context. But the author doesn't provide any examples and no
details.

One other approach you might take is to install a global via a
high-priority one-shot rule:

rule "startup"
salience 999999999
when
then
   kcontext.getKieRuntime().setGlobal(...,"...");
end

Lastly, you can simply use a static object in some class:

import foo.bar.Globals;
...
then
   Globals.foo.store( whatever );
...

-W

>
> Ideally, I need something like
> xxx.getKnowledgeBaseByName("mykb");
> or maybe
> xxx.getKnowledgePackageByName("mykb");
> or maybe
> xxx.getKnowledgeSessionByName("mykb");
>
> which ever of those I can call setGlobal on.
>
> FYI, our KIE stuff is container managed via maven integration with kie-wb -
> we do not control the lifecycle of any KIE objects kb, package, session,
> etc.
>
> Thanks again
>
>
>
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