Lille2010markp

●The SkyNet funding bill is passed. ●The system goes online on August 4th, 1997.●Human decisions are removed from strategic defense. ●SkyNet begins to learn at a geometric rate.●It becomes self-aware at 2:14am Eastern time, August 29th ●In a panic, they try to pull the plug. ●And, Skynet fights back

Mark Proctor

Project Lead

2

Business Logic integration Platform

DroolsGuvnor

DroolsFusion

DroolsFlow

DroolsExpert

Introduction

Drools Expert

Learn by Example

5

D a t e d a t ed o u b l e a m o u n ti n t t y p el o n g a c c o u n t N o

C a s h f l o w

l o n g a c c o u n t N od o u b l e b a l a n c e

A c c o u n t

D a t e s t a r tD a t e e n d

A c c o u n t i n g P e r i o d

Classes

6

AccountaccountNo balance

1 0

increase balance for AccountPeriod Credits

select * from Account acc, Cashflow cf, AccountPeriod apwhere acc.accountNo == cf.accountNo and cf.type == CREDIT cf.date >= ap.start and cf.date <= ap.end

decrease balance for AccountPeriod Debits

select * from Account acc, Cashflow cf, AccountPeriod apwhere acc.accountNo == cf.accountNo and cf.type == DEBIT cf.date >= ap.start and cf.date <= ap.end

AccountingPeriodstart end

01-Jan-07 31-Mar-07

trigger : acc.balance += cf.amount trigger : acc.balance -= cf.amount

Accountbalance

1 -25accountNo

Creating Views with Triggers

date amount type12-Jan-07 100 CREDIT 12-Feb-07 200 DEBIT 118-May-07 50 CREDIT 19-Mar-07 75 CREDIT 1

accountNo

date amount type12-Jan-07 100 CREDIT9-Mar-07 75 CREDIT

CashFlow

date amount type2-Feb-07 200 DEBIT

CashFlow

7

What is a Rule

• rule “<name>” <attribute> <value> when <LHS> then <RHS>end

Quotes on Rule names are optional if the rule name has no spaces.

salience <int>agenda-group <string>no-loop <boolean>auto-focus <boolean>duration <long>....

RHS can be any valid java. Or MVEL. Other languages could be added.

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Imperative vs Declarative

• public void helloMark(Person person) { if ( person.getName().equals( “mark” ) { System.out.println( “Hello Mark” ); }}

• rule “Hello Mark” when Person( name == “mark” ) then System.out.println( “Hello Mark” );end

LHS

RHS

specific passing of instances

Methods that must be called directly

Rules can never be called directly

Specific instances cannot be passed.

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S h o w e r ( t e m p e r a t u r e = = “ h o t ” )

P a t t e r n

F i e l d C o n s t r a i n t

R e s t r i c t i o n

E v a l u a t o r V a l u e

O b j e c t T y p e

F i e l d N a m e

What is a Pattern

10

rule “increase balance for AccountPeriod Credits” when ap : AccountPeriod() acc : Account( $accountNo : accountNo ) CashFlow( type == CREDIT, accountNo == $accountNo, date >= ap.start && <= ap.end, $ammount : ammount ) then acc.balance += $amount; end

select * from Account acc, Cashflow cf, AccountPeriod apwhere acc.accountNo == cf.accountNo and cf.type == CREDIT cf.date >= ap.start and cf.date <= ap.end

trigger : acc.balance += cf.amountPattern

Pattern Binding

field Binding

Literal Restriction

Variable Restriction

Multri Restriction - Variable Restriction

field Binding

Consequence (RHS)

Bringing it Together

11

AccountaccountNo balance

1 0

rule “increase balance for AccountPeriod Credits” when ap : AccountPeriod() acc : Account( $accountNo : accountNo ) CashFlow( type == CREDIT, accountNo == $accountNo, date >= ap.start && <= ap.end, $ammount : ammount ) then acc.balance += $amount; end

AccountingPeriodstart end

01-Jan-07 31-Mar-07

rule “decrease balance for AccountPeriod Debits” when ap : AccountPeriod() acc : Account( $accountNo : accountNo ) CashFlow( type == DEBIT, accountNo == $accountNo, date >= ap.start && <= ap.end, $ammount : ammount ) then acc.balance -= $amount; end

Rules as a “view”

Accountbalance

1 -25accountNo

date amount type12-Jan-07 100 CREDIT 12-Feb-07 200 DEBIT 118-May-07 50 CREDIT 19-Mar-07 75 CREDIT 1

accountNo

date amount type12-Jan-07 100 CREDIT9-Mar-07 75 CREDIT

CashFlowdate amount type

2-Feb-07 200 DEBIT

CashFlow

12

Patterns in more details

CashFlow( type == “credit” )

$ap : AccountPeriod()

CashFlow( date >= $ap.start )


CashFlow( date >= $ap.start && <= $ap.end )


CashFlow( type == “credit”,

date >= $ap.start && <= $ap.end )

13

More Pattern Examples

Person( $age : age )

Person( age == ( $age + 1 ) )

Person( $age : age )

Person( eval( age == $age + 1 ) )

Person( $age1 : age )

Person( $age2 : age )

eval( $age2 == $age1 + 1 )

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Person(age > 30 && < 40 || hair == “black”)

Person(pets[’rover’].type == “dog”)

Person(pets[0].type == “dog”)

Person(age > 30 && < 40 || hair in (“black”, “brown”) )

Person(pets contain $rover )

Person( (age > 30 && < 40 && hair == “black”)

||

(age > 50 && hair == “grey”) )

More Pattern Examples

15

What is a Production Rule System

ProductionMemory

WorkingMemory

Inference Engine

Pattern Matcher

Agenda(rules) (facts)

insertupdateretract

Repository of inserted Java instances

Codification of the business knowledge

Rules can changeon the fly

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A c c o u n t A c c o u n t i n g P e r i o d C a s h f l o w

v i e w 1 v i e w 2

m a i n v i e w

T a b l e s

V i e w s

V i e w

A c c o u n t A c c o u n t i n g P e r i o d C a s h f l o w

r u l e 1 r u l e 2

a g e n d a

O b j e c t T y p e s

R u l e s

a g e n d a

Production Rule SystemApproximated by SQL and Views

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rule “Print blance for AccountPeriod” salience -50 when ap : AccountPeriod() acc : Account( ) then System.out.println( acc.accountNo + “ : “ acc.balance ); end

Salience

Agenda1 increase balance

arbitrary2 decrease balance3 increase balance4 print balance

Conflict Resolution with Salience

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rule “increase balance for AccountPeriod Credits” ruleflow-group “calculation” when ap : AccountPeriod() acc : Account( $accountNo : accountNo ) CashFlow( type == CREDIT, accountNo == $accountNo, date >= ap.start && <= ap.end, $ammount : ammount ) then acc.balance += $amount; end

rule “Print blance for AccountPeriod” ruleflow-group “report” when ap : AccountPeriod() acc : Account( ) then System.out.println( acc.accountNo + “ : “ acc.balance ); end

ruleflow-group

RuleFlow

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Two Phase System

Working Memory Action

retract

modifyinsert

Agenda Evaluation

Select Rule to Fire

exit

No RuleFound

Fire Rule

Determine possible rules to

fire

RuleFound

Conditional Elements

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not Bus( color = “red” )

From CE for Expressions

exists Bus( color = “red” )

forall ( $bus : Bus( floors == 2 )

Bus( this == $bus, color == “red” ) )

forall ( $bus : Bus( color == “red” ) )

From CEfor Expressions

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rule “Find all the pets for a given owner”when $owner : Person( name == “mark” ) Pet( name == “rover” ) from $owner.pets

Using 'from' to reason over the nested list

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'from' can work on any expression, not just a nested field on a bound variable.


rule “Find People for given zip code”when $zipCode : ZipCode() Person( ) from $hbn.getNamedQuery(“Find People”) .setParameters( [ “zipCode” : $zipCode ] ) .list()

Hibernate session

Collect CE

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Collect CE

rule "accumulate"

when

$list : List( intValue > 100 )

from collect( Bus( color == "red" ) )

then

print "red buses “ + $list;

end

Accumulate CE

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Accumulate CE

rule "accumulate"

when

$sum : Number( intValue > 100 )

from accumulate( Bus( color == "red", $t : takings )

init( sum = 0 ),

action( sum += $t ),

result( sum ) )

then

print "sum is “ + $sum;

end

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Accumulate CE

rule "accumulate"

when


from accumulate( Bus( color == "red", $t : takings ) sum( $t ) )

then


end

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Accumulate CE

Patterns and CE's can be chained with 'from'

rule "collect"

when

$zipCode : ZipCode()


from accumulate( Bus( color == "red", $t : takings )

from $hbn.getNamedQuery(“Find Buses”)

.setParameters( [ “zipCode” : $zipCode ] )

.list(),

sum( $t ) )

then


end

TimersCalendars

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Timers

rule “name” timer 1m30swhen $l : Light( status == “on” )then SendEmail( “turn the light off” )

rule “name” timer (int: 0 1m30)when $l : Light( status == “on” )then SendEmail( “turn the light off” )

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Timers

rule “name” timer ( cron: 0 0/15 * * * * )when $l : Light( status == “on” )then sendEmail( “turn the light off” )

Field Name Mandatory? Allowed Values Allowed Special CharactersSeconds YES 0-59 , - * /Minutes YES 0-59 , - * /Hours YES 0-23 , - * /Day of month YES 1-31 , - * ? / L WMonth YES 1-12 or JAN-DEC , - * /Day of week YES 1-7 or SUN-SAT , - * ? / L #Year NO empty, 1970-2099 , - * /

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Calendars

rule "weekdays are high priority" calendars "weekday" timer (int:0 1h)when Alarm()then send( "priority high - we have an alarm” );end

rule "weekend are low priority" calendars "weekend" timer (int:0 4h)when Alarm()then send( "priority low - we have an alarm” );end

Truth MaintenanceInference

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TMS and Inference

rule "Issue Child Bus Pass"

when

$p : Person( age < 16 )

then

insert(new ChildBusPass( $p ) );

end

rule "Issue Adult Bus Pass"

when

$p : Person( age >= 16 )

then

insert(new AdultBusPass( $p ) );

end

Couples the logic

What happens when the Child stops being 16?

37

TMS and Inference

Bad● Monolithic● Leaky● Brittle integrity - manual maintenance

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TMS and Inference

A rule “logically” inserts an object When the rule is no longer true, the object is

retracted.

when

$p : Person( age < 16 )

then

logicalInsert( new IsChild( $p ) )

end

when


then

logicalInsert( new IsAdult( $p ) )

end

de-couples the logic

Maintains the truth by automatically retracting

39

TMS and Inference


when

$p : Person( )

IsChild( person =$p )

then

logicalInsert(new ChildBusPass( $p ) );

end

rule "Issue Adult Bus Pass"

when


IsAdult( person =$p )

then

logicalInsert(new AdultBusPass( $p ) );

end

The truth maintenance cascades

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TMS and Inference


when

$p : Person( )

not( ChildBusPass( person == $p ) )

then

requestChildBusPass( $p );

End The truth maintenance cascades

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TMS and Inference

Good● De-couple knowledge responsibilities● Encapsulate knowledge● Provide semantic abstractions for those encapsulation● Integrity robustness – truth maintenance

Tooling

43

Guided Editor

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Interactive Debugging

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Decision Tables

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DSLs

47

DSLs

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Rule Flow

Drools Fusion

50

$c : Custumer( type == “VIP” )BuyOrderEvent( customer == $c )

session.insert( event ) ;

Rule engines do not scale for CEP. They have a single point of insertion and are single threaded, CEP has concurrent streams of events.

Single Point of entry

Patterns, evaluate facts sequentially in a

single thread.

Scalability

51

$c : Custumer( type == “VIP )BuyOrderEvent( customer == $c ) from entry-point “Home Broker Stream”

Scalability

EntryPoint entryPoint = session.getEntryPoint( “Home Broker Stream” );entryPoint.insert( event ) ;

So lets allow multiple named entry points for

those streams

So now we can insert different streams

concurrently

Patterns can now optional specify their entry-point.

When not specified uses the “default” entry-point

52

All Fact life-cycles must be managed by the user, so retractions are manual.

declare StockTick @role( event )end

declare StockTick @role( event ) @timestamp( timestampAttr )

companySymbol : String stockPrice : double timestampAttr : longend

Automatic Life-Cycle Management

Just use the declare statement to declare a type as an event and it

will be retracted when it is no longer needed

The declare statement can also specify an internal model, that

external objects/xml/csv map on to. We support Smooks and JAXB

53

$c : Custumer( type == “VIP )$oe : BuyOrderEvent( customer == $c ) from entry-point “Home Broker Stream” BuyAckEvent( relatedEvent == $oe.id, this after[1s, 10s] $oe ) from entry-point “Stock Trader Stream”

● coincides

● before

● after

● meets

● metby

● overlaps

● overlappedby

● during

● includes

● starts

● startedby

● finishes

● finishedby

Operators

Rule engines do not have rich enough set of temporal comparison operators

BackAckEvent must occur between 1s and 10s 'after'

BuyOrderEvent

The Full set of Operators are supported

54

Operators

55

$c : Custumer( type == “VIP )$oe : BuyOrderEvent( customer == $c ) from entry-point “Home Broker Stream” not BuyAckEvent( relatedEvent == $oe.id, this after[1s, 10s] $oe ) from entry-point “Stock Trader Stream”

Operators

Existing Drools 'not' Conditional Elements can

be used to detect non-occurrence of events

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Rule engines react to events happening now, there is no temporal understanding of changes over time.

That isn't much without the ability to deal with aggregations, rules engines suck.

Sliding time windows

StockTicker( symbol == “RHAT” ) over window:time( 5s )

StockTicker( symbol == “RHAT” ) over window:length( 1000 )

5s

1000 tickers

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Aggregations

Rule Engines do not deal with aggregations

$n : Number( intValue > 100 ) from accumulate( $s : StockTicker( symbol == “RHAT” ) over window:time( 5s ), average( $s.price ) )

Over 5 seconds

Aggregate ticker price for RHAT over last 5

seconds

The pattern 'Number' reasons 'from' the accumulate result

$n : accumulate( $s : StockTicker( symbol == “RHAT” ) over window:time( 5s ), average( $s.price ) > 100 )

We can use some sugar to reduce verbosity

Drools Flow

59

Drools Flow

Integration● From loose coupling (decision services)● To advance integration (process rules)

Unification● Rules and processes are different types of business

knowledge assets● Infrastructure

● Timers/Schedulers● Testing● Communication/Services

● Tooling ● IDE● repository, management● Auditing●

A workflow engine combining processes and rules

Truth MaintenanceInference

61

Rules and processes

loosely coupledtightly coupled

spec

ific

gene

ric

DecisionServices

ProcessRules

SC

OP

E

COUPLING

?

62

Business Logic Lifecycle

63

Example

64

RuleFlowGroup

Workflow can control my rules?

65

RuleFlowGroup

Rule Flow Group

66

RuleFlowGroup

67

Constraints

Java code constraint

68

Constraints

Rules can control my workflow?

LHS “when”Rule Constraint

69

Example

Business decisions are externalized using a decision service

rule Decision1 when // conditions then // actionsend



70

Example

What if there is a lot of business logic like this?






















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RulesEngine

Flow of Control

ProcessEngine

72

RulesEngine

Inversion of Control

ProcessEngine

Age

nda

73

Self monitoring and adaptive

declare ProcessStartedEvent

@role( event )

end

rule "Number of process instances above threshold" when

Number( nbProcesses : intValue > 1000 )

from accumulate(

e: ProcessStartedEvent( processInstance.processId == "com.sample.order.OrderProcess" )

over window:size(1h),

count(e) )

then

System.err.println( "WARNING: Nb of order processes in the last hour > 1000: " + nbProcesses );

end

74

Domain Specific Processes

75

Domain Specific Processes

76

Integrated debug and audit

Unified API

DefinitionsRuntime

Language

78

jBPMFile file = new File (“.....”); // file to XML process definition

ProcessDefinition processDefinition = ProcessDefinition.parseXmlString( IoUtils.FileToString( file ) );

ProcessInstance processInstance = new ProcessInstance(processDefinition);

JessRete engine = new Rete();

FileReader file = new FileReader("myfile.clp");

Jesp parser = new Jesp(file, engine);

parser.parse(false);

Esper

EPServiceProvider epService = EPServiceProviderManager.getDefaultProvider();

EPStatement countStmt = admin.createEPL( "...." );

countStmt.start();

Definitions

79

Drools Flow

KnowledegBuilder kbuilder = KnowledgeBuilderFactory.newKnowledgeBulider();

kbuilder.addResource( ResourceFactory.newClassPathResource( “myflow.drf”, ResourceType.DRF );

If ( kbuilder.hasErrors() ) { log.error( kbuilder.hasErrors().toString() );}

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

Definitions

80

Drools Expert

KnowledegBuilder kbuilder = KnowledgeBuilderFactory.newKnowledgeBulider();

kbuilder.addResource( ResourceFactory.newClassPathResource( “myrules.drl”, ResourceType.DRL );

If ( kbuilder.hasErrors() ) { log.error( kbuilder.hasErrors().toString() );}

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

Definitions

81

Drools Integration Deployment Descriptors

<change-set> <add> <resource source='classpath:myapp/data/myflow.drf' type='DRF' /> <resource source='http:myapp/data/myrules.drl' type='DRL' />

<resource source='classpath:data/IntegrationExampleTest.xls' type="DTABLE">

<decisiontable-conf input-type="XLS" worksheet-name="Tables_2" />

</resource> <add></change-set>

KnowledegBuilder kbuilder = KnowledgeBuilderFactory.newKnowledgeBulider();kbuilder.addResource( ResourceFactory.newFileResource( “changeset.xml”, ResourceType.ChangeSet );

Unified Event Model

Mixins Interface Markers

85

Stateful KnowledgeSession

86

Knowledge Runtime

87

Coming in 5.1

BPMN2 (80% of Workflow) Integration

● OSGi ready● Spring● Camel

Seamless Remoting Simulation/Testing New Rete Algorithm “true modify”

88

Spring + camel

from("direct:test-with-session").to("drools:sm/ksession1?dataFormat=drools-xstream");

89

Questions?Questions?

• Dave Bowman: All right, HAL; I'll go in through the emergency airlock.

• HAL: Without your space helmet, Dave, you're going to find that rather difficult.

• Dave Bowman: HAL, I won't argue with you anymore! Open the doors!

• HAL: Dave, this conversation can serve no purpose anymore. Goodbye. Joshua: Greetings, Professor Falken.

Stephen Falken: Hello, Joshua.Joshua: A strange game. The only winning move is not to play. How about a nice game of chess?

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Lille2010markp

Technology

c c o u n t n oa c c

p thenrequestchildbuspass

p endmaintains

p end39

c c o u n t n o d o

t thenprint sum

o u n t d o u b

cco unta c c o u n t