On 14/02/2011 18:10, Edson Tirelli wrote:
The current version of Drools does not support dynamic changes in
"type declarations" and I don't see this changing anytime soon. The
reason is that not only the actual fact would require changes, but the
actual knowledge base would require changes as several nodes might be
referencing the old class.
So, to update a fact type you need to recreate the knowledge base.
This is the same, BTW, than changing one of your fact classes in your
application jars... you need to recompile the knowledge base or you
will end up with class cast exceptions, sooner or later.
Longer term there are two ways to achieve this
1) type declarations can only be modified if there is no data on them
and the existing rules are still valid after the change, i.e. it will
not effect the current state.
2) If ther eare existing facts a migration script must be provided that
handles the mapping as all beans would need to be copied to the new type
declaration.
Mark
Edson
2011/2/14 delete <[email protected] <mailto:[email protected]>>
Hi.
I have such declaration of type
declare Contact
firstName : String
end
then I want to add new property to this type. so the next version is
declare Contact
firstName : String
newField : String
end
this type declaration is in separate drl file.
then I add this new type to current KnowledgeBase.
but when I execute knowledgeBase.getFactType("test.package",
"Contact");
I get old version of Contact.
During debugging I found the place where is should be upgraded in the
KnowledgeBase.
org.drools.common.AbstractRuleBase.mergePackage
there is
// merge the type declarations
if ( newPkg.getTypeDeclarations() != null ) {
// add type declarations
for ( TypeDeclaration type :
newPkg.getTypeDeclarations().values() ) {
// @TODO should we allow overrides? only if the
class is not
in use.
if ( !pkg.getTypeDeclarations().containsKey(
type.getTypeName() ) ) {
// add to package list of type declarations
pkg.addTypeDeclaration( type );
}
}
}
so according this comments it's not possible to upgrade Type on
the fly.
Am I missing something?
Does someone had such problems or know the workaround.
Thanks in advance,
Yuriy
--
View this message in context:
http://drools-java-rules-engine.46999.n3.nabble.com/Type-Declaration-upgrade-tp2491975p2491975.html
Sent from the Drools - User mailing list archive at Nabble.com.
_______________________________________________
rules-users mailing list
[email protected] <mailto:[email protected]>
https://lists.jboss.org/mailman/listinfo/rules-users
--
Edson Tirelli
JBoss Drools Core Development
JBoss by Red Hat @ www.jboss.com <http://www.jboss.com>
_______________________________________________
rules-users mailing list
[email protected]
https://lists.jboss.org/mailman/listinfo/rules-users
_______________________________________________
rules-users mailing list
[email protected]
https://lists.jboss.org/mailman/listinfo/rules-users
