Hi Esteban
Unfortunately I haven't had time to work further on this issue, so I don't have an answer yet.
All I can say for now is it seems that the ReaderResources are being created along with the URLResource each time. This is evidenced by the details below.
In my test, I have the following changeset based on the mortgages sample (I have changed my hosting port):
----------------------------------------------------------------------------------------------
<add>
</add>
</change-set>
----------------------------------------------------------------------------------------------
This changeset can be read as a UrlResource, ClassPathResource or ByteArrayResource. I then use the following code to initialise the KnowledgeAgent:
----------------------------------------------------------------------------------------------
SystemEventListenerFactory.setSystemEventListener(new PrintStreamSystemEventListener(System.out));
KnowledgeAgent kagent = KnowledgeAgentFactory.newKnowledgeAgent("MortgageAgent");
Resource changeset = ResourceFactory.newClassPathResource("ChangeSet.xml");
kagent.applyChangeSet(changeset);
----------------------------------------------------------------------------------------------
Within the System event listener output, I see that the KnowledgeAgent picks up all of the KnowledgeDefinitions from Drools and creates them as new UrlResources. Next, it picks up the KnowledgeDefinitions from drools and creates these all as null ReaderResources. Here is some output from my System event listener:
----------------------------------------------------------------------------------------------
[2012-01-17 10:32:32,577:debug] KnowledgeAgent rebuilding KnowledgeBase using ChangeSet
[2012-01-17 10:32:33,410:debug] KnowledgeAgent building resource map
[2012-01-17 10:32:33,411:debug] KnowledgeAgent no resource mapped for rule=[Rule name=Dummy rule, agendaGroup=MAIN, salience=0, no-loop=false]
[2012-01-17 10:32:33,412:debug] KnowledgeAgent mapping resource=[ReaderResource resource=null encoding='null'] to KnowledgeDefinition=org.drools.rule.TypeDeclaration@b10723b8
[2012-01-17 10:32:33,412:debug] KnowledgeAgent notifier subscribing to resource=[ReaderResource resource=null encoding='null']
[2012-01-17 10:32:33,412:debug] ResourceChangeNotification subscribing listener=org.drools.agent.impl.KnowledgeAgentImpl@54b216b3 to resource=[ReaderResource resource=null encoding='null']
[2012-01-17 10:32:33,412:debug] ResourceChangeScanner subcribing notifier=org.drools.io.impl.ResourceChangeNotifierImpl@77f06d35 to resource=[ReaderResource resource=null encoding='null']
[2012-01-17 10:32:33,412:debug] KnowledgeAgent mapping resource=[ReaderResource resource=null encoding='null'] to KnowledgeDefinition=org.drools.rule.TypeDeclaration@a562a3f
[2012-01-17 10:32:33,412:debug] KnowledgeAgent mapping resource=[ReaderResource resource=null encoding='null'] to KnowledgeDefinition=org.drools.rule.TypeDeclaration@9baaa763
[2012-01-17 10:32:33,412:debug] KnowledgeAgent mapping resource=[ReaderResource resource=null encoding='null'] to KnowledgeDefinition=org.drools.rule.TypeDeclaration@fadf3f01
[2012-01-17 10:32:33,412:info] KnowledgeAgent new KnowledgeBase now built and in use
[2012-01-17 10:32:33,412:debug] KnowledgeAgent finished rebuilding KnowledgeBase using ChangeSet
----------------------------------------------------------------------------------------------
As a result of these ReaderResources existing, the ResourceChangeScanner cannot run as the ReaderResources do not have a modified date.
At the moment I am not sure why these ReaderResources are created but I would imagine they are there to represent the drools domain facts. There are four facts in the mortgages sample and four ReaderResources are created.
Regards
Dean