Drools Fusion滑动窗口样本不工作

Question

我是一个流口水的新手，正在尝试滑动窗口的概念。

我的问题是检测两个销售事件中是否至少发生了成功的交易。我总是以“一次销售发生了两次事件”的形式得到结果，即使这样的事件是否发生过。

-------------drl公司----------

declare Sale
@role( event )
end

rule "Identify more than a single valid sale event"

//The variable saleHappened would be set to Y if a successful transaction

when sale: Sale ( saleHappened == "Y")  over window:length(2)  from entry-point MyEntryPoint

then

System.out.println("A sale has happened over 2 events" );

end

-------------代码----------

public class DroolsTest {

    public static final void main(String[] args) {
        try {

            // load up the knowledge base 
            KnowledgeBase kbase = readKnowledgeBase(); 

            StatefulKnowledgeSession ksession = kbase.newStatefulKnowledgeSession(); 

            WorkingMemoryEntryPoint entryPoint = ksession.getWorkingMemoryEntryPoint("MyEntryPoint");


            Sale sale = new Sale();

            sale.setSaleHappened("N");
            entryPoint.insert(sale);


            Sale sale2 = new Sale();

            sale2.setSaleHappened("N");
            entryPoint.insert(sale2);


            ksession.fireAllRules();

            ksession.dispose(); 

        } catch (Throwable t) {
            t.printStackTrace();
        }
    }


    private static KnowledgeBase readKnowledgeBase() throws Exception {

        KnowledgeBuilder kbuilder = KnowledgeBuilderFactory.newKnowledgeBuilder(); 
        kbuilder.add(ResourceFactory.newClassPathResource("Sample.drl"), ResourceType.DRL); 
        KnowledgeBuilderErrors errors = kbuilder.getErrors(); 
        if (errors.size() > 0) { 
                for (KnowledgeBuilderError error: errors) { 
                        System.err.println(error); 
                } 
                throw new IllegalArgumentException("Could not parse knowledge."); 
        } 

        final KnowledgeBaseConfiguration kbConfig = KnowledgeBaseFactory.newKnowledgeBaseConfiguration(); 
        kbConfig.setOption(EventProcessingOption.STREAM); 
        KnowledgeBase kbase = KnowledgeBaseFactory.newKnowledgeBase(kbConfig); 
        kbase.addKnowledgePackages(kbuilder.getKnowledgePackages()); 
        return kbase; 
    }

    public static class Sale {

        public Sale () {

        }

        public String getSaleHappened() {
            return saleHappened;
        }

        public void setSaleHappened(String saleHappened) {
            this.saleHappened = saleHappened;
        }

        private String saleHappened;




    }

}

Answer 1

这与Bug 787118有关-长度滑动窗口保留所有事件。在bugzilla条目中解释了滑动窗口事件触发的概念以及事件如何不会从窗口中掉下来。

可按如下方式固定：

--------------drl--------------------

declare Sale
@role( event )
end

declare window Ticks
    Sale()
        over window:length( 5 )
        from entry-point MyEntryPoint
end


rule "More than 2 sale suceess in 5 events"
when     Number($cnt : intValue,intValue > 2) 
from    accumulate( Sale ( saleHappened == "Y" ) from window Ticks,  count(1) )
then
    System.out.println("A sale has happened over " + $cnt +" events" );
end