Re: [rules-dev] Drools on android -reply
On 2 January 2012 14:30, Matthew Versaggi <profversaggi(a)gmail.com> wrote:
Here's what I got working and when it failed .... it was just the
basic
'hello world' kind of stuff:
Worked:
final KnowledgeBuilder kbuilder =
KnowledgeBuilderFactory.newKnowledgeBuilder();
Died:
// this will parse and compile in one step
kbuilder.add(ResourceFactory.newClassPathResource("HelloWorld.drl",
DroolsTest.class), ResourceType.DRL);
LogCat:
01-02 13:13:17.684: E/AndroidRuntime(537): java.lang.RuntimeException:
Unable to start activity
ComponentInfo{com.versaggi.android.droolsandroidtest/com.versaggi.android.droolsandroidtest.DroolsAndroidTestActivity}:
java.lang.NullPointerException
I've seen NPEs thrown up from down in the Drools gears when the DRL
resource could not be found. Make sure that
ResourceFactory.newClassPathResource("HelloWorld.drl",
DroolsTest.class)
is != null.
I had to re-compile the CompositeClassLoader.java file and then reinsert it
into the drools-api-5.1.0.M2.jar file to get past this issue:
"A small modification is needed in org.drools.util.CompositeClassLoader.
Apparently, the Android JVM doesn't allow null as the parent classloader
so I changed that to super(CompositeClassLoader.class.getClassLoader())in the
constructor, and that works fine."
Yes, that's come up in other Java environments as well, and IIRC been fixed
on the way towards 5.2.0. )There ought to be a closed JIRA, if s.o. cares
to look it up.)
-W
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