[rules-dev] Locating objects by query/BC

[Mark Proctor]

ok thanks, I reproduced the problem with the following below. If you 
change the String insertion order it works. I'll get this fixed over the 
weekend:
     @Test
     public void testQueryWithObject() throws Exception {
         String str = "" +
             "package org.drools.test  \n" +

             "import java.util.List\n" +
             "import java.util.ArrayList\n" +

             "global List list\n" +

             "dialect \"mvel\"\n" +
             "\n" +

             "import org.drools.integrationtests.BackwardChainingTest.Q\n" +
             "import org.drools.integrationtests.BackwardChainingTest.R\n" +
             "import 
org.drools.integrationtests.BackwardChainingTest.S\n" +

             "query object(Object o)\n" +
             "    o := Object() \n" +
             "end\n" +

             "rule collectObjects when\n" +
             "   String( this == 'go1' )\n" +
             "   object( o; )\n" +
             "then\n" +
             "   list.add( o );\n" +
             "end\n" +


             "rule init when\n" +
             "   String( this == 'init' )\n" +
             "then\n" +
             " insert( new Q(1) );\n " +
             " insert( new Q(5) );\n " +
             " insert( new Q(6) );\n " +
             " insert( new R(1) );\n " +
             " insert( new R(4) );\n " +
             " insert( new R(6) );\n " +
             " insert( new R(2) );\n " +
             " insert( new S(2) );\n " +
             " insert( new S(3) );\n " +
             " insert( new S(6) );\n " +
             "end\n" +
             "";

         KnowledgeBuilder kbuilder = 
KnowledgeBuilderFactory.newKnowledgeBuilder();
         kbuilder.add( ResourceFactory.newByteArrayResource( 
str.getBytes() ),
                           ResourceType.DRL );

         if ( kbuilder.hasErrors() ) {
             fail( kbuilder.getErrors().toString() );
         }

         KnowledgeBase kbase = KnowledgeBaseFactory.newKnowledgeBase();
         kbase.addKnowledgePackages( kbuilder.getKnowledgePackages() );

         kbase = SerializationHelper.serializeObject( kbase );

         StatefulKnowledgeSession ksession = 
kbase.newStatefulKnowledgeSession();
         List<Integer> list = new ArrayList<Integer>();
         ksession.setGlobal( "list", list );

         ksession.insert( "go1" );
         ksession.fireAllRules();

         ksession.insert( "init" );
         ksession.fireAllRules();

         System.out.println( list );
     }

Mark
On 25/06/2011 11:22, Wolfgang Laun wrote:
> // This rule prints all objects in WM.
> rule findObject
> when
>     $o: Object()
> then
>     System.out.println( "Object: " + $o );
> end
>
> Happily I get
>     Object: 42
>     Object: a String object
>     Object: org.drools.reteoo.InitialFactImpl at 4dde85f0
>
> Now the query way:
>     query object( Object o )
>         o := Object()
>     end
>     rule findObjectByQuery
>     when
>         object( $a ; )
>     then
>         System.out.println( "Object by query: " + $a );
>     end
>
> Surprisingly, I get just one:
>     Object by query: org.drools.reteoo.InitialFactImpl at 4dde85f0
>
> A marvellous effect can be observed when the condition in rule
> findObjectByQuery is modified to
>     when
>         Object()
>         object( $a ; )
>     then
> I'd have guessed that the above result would appear repeatedly, once 
> for each Object in WM,
> but that's not so. For N-1 facts the rule fires N*(N+1)/2 times, 
> showing the "initial object"
> N times, the first inserted object N-1 times, the second one N-2 times 
> and, finally, the last one
> once.
> Object by query: 42
> Object by query: org.drools.reteoo.InitialFactImpl at 4dde85f0
> Object by query: a String object
> Object by query: 100
> Object by query: 42
> Object by query: org.drools.reteoo.InitialFactImpl at 4dde85f0
> Object by query: a String object
> Object by query: org.drools.reteoo.InitialFactImpl at 4dde85f0
> Object by query: a String object
> Object by query: org.drools.reteoo.InitialFactImpl at 4dde85f0
>
> -W
>
>
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> rules-dev at lists.jboss.org
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