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[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
我有一個通過Guvnor控制台創建的流口水規則,如果滿足條件,該規則將驗證事實並將事實插入工作內存中。 規則是:
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
執行規則的Java代碼如下
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);
一切看起來都很不錯,輸出如下:
Hello from Drools
After drools execution
count 2
我似乎找不到找到在我的Java代碼中獲取EligibilityInquiry
事實對象並獲取上述規則中設置的屬性的方法( serviceName
和status
)。 我使用了StatefulSession
方法。
屬性文件具有通過用戶名和密碼進行基本身份驗證的快照鏈接。 總共有2個事實: EligibilityInquiry
和Eligibility
。
我對流口水是相當陌生的,對上述任何幫助都將受到贊賞。
(注意:我固定了語句的順序,即錯字(“ XX”),並從輸出中刪除了注釋。不足為奇。)
此摘要假定EligibilityInquiry
中也聲明了EligibilityInquiry
。
FactType eligInqFactType = ruleBase.getFactType("mortgages", "EligibilityInquiry");
Class<?> eligInqClass = eligInqFactType.getFactClass();
ObjectFilter filter = new FilterByClass( eligInqClass );
Collection<Object> eligInqs = workingMemory.getObjects( filter );
過濾器是
public class FilterByClass implements ObjectFilter {
private Class<?> theClass;
public FilterByClass( Class<?> clazz ){
theClass = clazz;
}
public boolean accept(Object object){
return theClass.isInstance( object );
}
}
您可能還會使用query
,它需要大約相同數量的代碼。
// 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,您可以調用workingMemory.getObjects()
並迭代該集合並檢查每個對象的類。
for( Object obj: workingMemory.getObjects() ){
if( obj.isInstance( eligInqClass ) ){
System.out.println( eligInqClass.cast( eligInqObj ) );
}
}
或者,您可以(有或沒有插入創建的EligibilityInquiry對象作為事實)將事實添加到global java.util.List eligInqList
並在Java代碼中進行迭代。 請注意,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 ) );
}
可能是一個尷尬的富裕階層。
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