1. 如何建立企業級應用的
商業規則引擎
李日貴 Jini Gary Lee
王文農 Steven Wang

2. 為何要使用規則引擎

3. Java Multi-tiers
• Struts
• JSF
• SpringMVC
• Tapestry
• Wicket
MVC
Front Tier
DAO
Persistence Tier
Buisiness Logic
Middle Tier
• Hibernate
• MyBatis
• JDO
• JPA

4. RuleEngine 的好處
• 宣告式的開發
• 區隔商業邏輯與資料處理的程式
• 效能與擴充性
• 集中控管商業邏輯
• 簡易的工具
• 可閱讀的規則

5. Rule ?
When
(Conditions)
THEN
(Actions)

6. Rule Engine
Working
Memory
Production
Memory
Match Rules
Resolve
Conflicts
(Agenda)
Fire RulesFact Rules

7. Forward Chaining
Rule
Base
Working
Memory
Determine possible
rules to fire
Select
Rules
to Fire
Conflict
Resolution
Strtegy
Exit
Fire Rule
Conflict Set
Rule Found
No Rule Found
Exit if specified by rule

8. Rete
• Dr. Charles L. Forgy , 1974
• Data struture
– List of elements
– Tree-Strutured Sorting Network
• Algorithm
– Rule Compilation
– Runtime Execution

9. http://en.wikipedia.org/wiki/File:Rete.svg

10. JSR-94
• Java Rule Engine API
• JSR94 provides
– Rule Administration
– Rule Runtime APIs
– Rule Language (RuleML)

11. JSR94 APIs
• Register and unregister rules
• Parse Rules
• Inspect rule metadata
• Execute Rules
• Retrieve Results
• Filter Results

12. Rule Engines
• Commercial
– Oracle Business Rules
– IBM iLOG
– Pega Rules
– FICO Blaze Advisor
– JESS ( JSR94 RI )
• Opensources
– JBOSS Drools
– OpenRules

13. JESS

14. JESS
• A Rule Engine
• A scripting environment in Java
JESS  Java
• Rete algorithm
• LISP-like syntax
• Can be licensed for commercial use, no
cost for academic use

15. JESS language
• *.clp ( in JessDE )

16. Basic Syntax
• (a b c) – List of tokens
• (1 2 3) – List of Integers
• (+ 1 2) – Expression
• (“Hello world”) – String
• (foo ?x ?y) – Function

17. Define Functions
(deffunction max(?a ?b)
(if(> ?a ?b) then
(return ?a)
else
(return ?b)))
(printout t (max 3 5))

18. Define Advices
(defadvice before + (bind $?argv ( create$
$?argv 1 )))
(printout t (+ 2 3) crlf)
(undefadvice +)
(printout t (+2 3) crlf)

19. Define Template
(deftemplate automobile
"A specific car."
(slot make)
(slot model)
(slot year (type INTEGER))
(slot color (default white)))
(assert (automobile (model CAMERY) (make TOYOTA) (year 2008)))
(assert (automobile (model 520i) (make BMW) (year 2013)))
(facts)

20. Define class
(import domain.Account)
(deftemplate Account (declare (from-class Account)))
(bind ?a (new Account))
(add ?a)
(facts)
(modify 0 (id 1) (name jini))
(facts)
(bind ?a (new Account))
(add ?a)
(?a setId 2) (?a setName steven)
(printout t (?a getId) "-" (?a getName) "." crlf)
(facts)
(update ?a)
(facts)

21. Define rule
(deftemplate person (slot name) (slot age))
(defrule vote "Can you vote"
(person {age < 18})
=>
(printout t "No, you can't vote" crlf)
)
(assert (person (age 17)))
(run)

22. Use Java
(bind ?map (new java.util.HashMap))
(call ?map put "A" "Apple")
(call ?map put "B" "Banana")
(call ?map put "C" "Cherry")
(printout t (call ?map get "B"))

23. JessML
<?xml version=‘1.0’ encoding=‘UTF-8’?>
<rulebase xmlns=‘http://www.jessrules.com/JessML/1.0’>
<template>
<name>person</name><slot>name</slot>
<value type=‘SYMBOL’>nil</value>
</template>
<facts>
<name>course</name>
<fact>
<name>id</name><value type=‘INTEGER’>1</value>
</fact>
</facts>
<rule>
<lhs>..</lhs>
<rhs>..</rhs>
</rule>
</rulebase>

24. JSR 94
public class JessRule {
private static final String RULE_SERVICE_PROVIDER
=“org.jcp.jsr94.jess”;
public void run(){
Class.forName(“org.jcp.jsr94.jess.RuleServiceProviderImpl”);
RuleServiceProvider serviceProvider =
RuleServiceProviderManager
.getRuleRuleServiceProvider(RULE_SERVICE_PROVIDER );
}
}

25. Drools

26. Setup RuleIDE

27. Start Drools Project

28. simple Rule
package javatwo.license
rule “Check age < 18”
when
$a : Applicant(age < 18)
then
$a.setValid(false);
end

29. Execute DRL
KnowledgeBuilder kbuilder =
KnowledgeBuilderFactory.newKnowledgeBuilder();
kbuilder.add(ResourceFactory.newClassPathResource("javatwo/
license/licenseApplication.drl"), ResourceType.DRL );
KnowledgeBase kbase =
KnowledgeBaseFactory.newKnowledgeBase();
kbase.addKnowledgePackages(kbuilder.getKnowledgePackage
s());
StatelessKnowledgeSession ksession =
kbase.newStatelessKnowledgeSession();
Applicant applicant = new Applicant(1, "Kevin", 15);
ksession.execute(applicant);

30. Nature Language
kbuilder.add(ResourceFactory.newClassPathResource("nature.dsl"),
ResourceType.DSL );
kbuilder.add(ResourceFactory.newClassPathResource("nature.dslr"),
ResourceType.DSLR );
nature.dsl
[condition][]Person is {name}=$person : Person(name=='{name}')
[consequence][]SayHello=System.out.println("Hello "+$person.getName());
nature.dslr
expander nature.dsl
rule "Nature language"
when
Person is gary
then
SayHello
end

31. Chinese ?!
cnature.dsl
[condition][]姓名是 {name}=$person : Person(name=='{name}')
[consequence][]打招呼=System.out.println("Hello
"+$person.getName());
cnature.dslr
expander cnature.dsl
rule "Nature language"
when
姓名是 gary
then
打招呼
end

32. JSR 94
public class DroolsRule {
private static final String RULE_SERVICE_PROVIDER
=“http://drools.org/”;
public void run(){
Class.forName(“org.drools.jsr94.rules.RuleServiceProviderImpl
”);
RuleServiceProvider serviceProvider =
RuleServiceProviderManager
.getRuleRuleServiceProvider(RULE_SERVICE_PROVIDER );
}
}

33. Script

34. JSR-223 support
• JSR-223
– javax.script
• The scripting API consists of interfaces and
classes that define Java Scripting Engines and
provides a framework for their use in Java
applications.
– since Java 1.6
• Before JSR-223
– Use BeanShell or etc..
– API not standard

35. JSR-223 support

36. Scripting API component
relationships

37. Eval Script
// create a script engine manager
ScriptEngineManager factory = new ScriptEngineManager();
// create a Javascript engine
ScriptEngine engine = factory.getEngineByName(“JavaScript”);
// evaluate Javascript code from String
engine.eval(“print(‘Hello world’)”);

38. Eval File
// create a script engine manager
ScriptEngineManager factory = new ScriptEngineManager();
// create a Javascript engine
ScriptEngine engine = factory.getEngineByName(“JavaScript”);
// evaluate Javascript code from given file – specified by first argument
engine.eval( new java.io.FileReader(args[0]));

39. Eval Variable
ScriptEngineManager factory = new ScriptEngineManager();
ScriptEngine engine = factory.getEngineByName(“JavaScript”);
File f = new File(“test.txt”);
// expose File object as variable to script
engine.put(“file”,f);
// evaluate a script string. The script accesses “file” variable and calls
method on it
engine.eval(“print(file.getAbsolutePath())”);

40. Eval Script Function
ScriptEngineManager factory = new ScriptEngineManager();
ScriptEngine engine = factory.getEngineByName(“JavaScript”);
// Javascript code in a String
String script = “function hello(name) { print(‘Hello’+name); }”;
engine.eval(script);
// javax.script.Invocable is an optional interface. Check whether your
script engine implements or not! Note that the Javascript engine
implements Invocable interface.
Invocable inv = (Invocable) engine;
inv.invokeFunction(“hello”, “Scripting!!”);

41. Drools

42. JESS

43. But their language/spec…

44. We want..

45. We are..

46. Case 1保費計算
• 不同險種會有不同的保費計算方式，公式
和因子也可能會不相同
• 複雜計算方式需要特殊的方式，最好能夠
在不須知道太多的情況下，Plug-In進來

47. 條件 公式 因子
因
子
公
式
畫
面
D
B
其
他
公式：Ａ＋Ｂ／Ｃ－Ｄ
因子 Ａ：畫面
Ｂ：Ｄatabase
Ｃ：另一個公式Ｘ＋Ｙ
Ｄ：其他系統
Ｘ：常數
Ｙ：Ｄatabase
ＰｌｕｇＩｎ

48. 保費公式設定

49. 模擬保費公式設定

50. Case 2核保檢核
• 報價轉保單時，有許多企業邏輯需要被檢
核
• 這些邏輯，我們不希望hardcode在程式內

51. 條件
規則 結果
規則 結果
規則 結果
.
.
.
1.單一結果或多組結果
2.根據結果進行後續處理
- DataBase操作
-Java操作
-畫面相關操作
ＰｌｕｇＩｎ
Java
Script
SQL
.
.
.

52. 核保檢核設定

53. 模擬核保檢核設定

54. 測試案例：保單內容

55. Rule & Engine

56. Find Match Rules

57. 計算保費處理

58. 核保檢核處理

59. Execute

60. 缺點
1. 不是使用宣告的方法，而是定義處理過程
2. 複雜的業務邏輯，可能會需要巢狀條件結
構，這會使得Rule難以閱讀且容易出錯
3. 可能需要定義代碼處理決定表，或建立更
好的Rule Engine
4. Multiple Script Language將會難以維護

61. 優點
1. 對開發者來說較直接
2. 物件可由Java或Script內產生並共用
3. Rule可以更加的動態