[英]How a fact in the java code and a fact in the .drl are bound in drools?
[英]Access to Drools returned fact object in Java Code
我有一个通过Guvnor控制台创建的流口水规则,如果满足条件,该规则将验证事实并将事实插入工作内存中。 规则是:
1. | rule "EligibilityCheck001"
2. | dialect "mvel"
3. | when
4. | Eligibility( XXX== "XXX" , YYY== "YYY" , ZZZ== "ZZZ" , BBB == "BBB" )
5. | then
6. | EligibilityInquiry fact0 = new EligibilityInquiry();
7. | fact0.setServiceName( "ABCD" );
8. | fact0.setMemberStatus( true );
9. | insert(fact0 );
10. | System.out.println( "Hello from Drools");
11. | end
执行规则的Java代码如下
RuleAgent ruleAgent = RuleAgent.newRuleAgent("/Guvnor.properties");
RuleBase ruleBase = ruleAgent.getRuleBase();
FactType factType = ruleBase.getFactType("mortgages.Eligibility");
Object obj = factType.newInstance();
factType.set(obj, "XXX", "XXX");
factType.set(obj, "YYY", "YYY");
factType.set(obj, "ZZZ", "XXX");
factType.set(obj, "BBB", "BBB");
WorkingMemory workingMemory = ruleBase.newStatefulSession();
workingMemory.insert(obj);
workingMemory.fireAllRules();
System.out.println("After drools execution");
long count = workingMemory.getFactCount();
System.out.println("count " + count);
一切看起来都很不错,输出如下:
Hello from Drools
After drools execution
count 2
我似乎找不到找到在我的Java代码中获取EligibilityInquiry
事实对象并获取上述规则中设置的属性的方法( serviceName
和status
)。 我使用了StatefulSession
方法。
属性文件具有通过用户名和密码进行基本身份验证的快照链接。 总共有2个事实: EligibilityInquiry
和Eligibility
。
我对流口水是相当陌生的,对上述任何帮助都将受到赞赏。
(注意:我固定了语句的顺序,即错字(“ XX”),并从输出中删除了注释。不足为奇。)
此摘要假定EligibilityInquiry
中也声明了EligibilityInquiry
。
FactType eligInqFactType = ruleBase.getFactType("mortgages", "EligibilityInquiry");
Class<?> eligInqClass = eligInqFactType.getFactClass();
ObjectFilter filter = new FilterByClass( eligInqClass );
Collection<Object> eligInqs = workingMemory.getObjects( filter );
过滤器是
public class FilterByClass implements ObjectFilter {
private Class<?> theClass;
public FilterByClass( Class<?> clazz ){
theClass = clazz;
}
public boolean accept(Object object){
return theClass.isInstance( object );
}
}
您可能还会使用query
,它需要大约相同数量的代码。
// DRL code
query "eligInqs"
eligInq : EligibilityInquiry()
end
// after return from fireAllRules
QueryResults results = workingMemory.getQueryResults( "eligInqs" );
for ( QueryResultsRow row : results ) {
Object eligInqObj = row.get( "eligInq" );
System.out.println( eligInqClass.cast( eligInqObj ) );
}
或者,您可以调用workingMemory.getObjects()
并迭代该集合并检查每个对象的类。
for( Object obj: workingMemory.getObjects() ){
if( obj.isInstance( eligInqClass ) ){
System.out.println( eligInqClass.cast( eligInqObj ) );
}
}
或者,您可以(有或没有插入创建的EligibilityInquiry对象作为事实)将事实添加到global java.util.List eligInqList
并在Java代码中进行迭代。 请注意,需要StatefulKnowledgeSession
的API(而不是WorkingMemory
)。
// Java - prior to fireAllRules
StatefulKnowledgeSession kSession() = ruleBase.newStatefulSession();
List<?> list = new ArrayList();
kSession.setGlobal( "eligInqList", list );
// DRL
global java.util.List eligInqList;
// in a rule
then
EligibilityInquiry fact0 = new EligibilityInquiry();
fact0.setServiceName( "ABCD" );
fact0.setMemberStatus( true );
insert(fact0 );
eligInqList.add( fact0 );
end
// after return from fireAllRules
for( Object elem: list ){
System.out.println( eligInqClass.cast( elem ) );
}
可能是一个尴尬的富裕阶层。
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