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

Business Logic integration Platform

DroolsGuvnor

DroolsFusion

DroolsFlow

DroolsExpert

Introduction

Drools Expert

Learn by Example

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

AccountaccountNo balance

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

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.

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

specific passing of instances

Methods that must be called directly

Rules can never be called directly

Specific instances cannot be passed.

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

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

AccountaccountNo balance

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

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 )

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 )

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

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

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

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

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

Two Phase System

Working Memory Action

retract

modifyinsert

Agenda Evaluation

Select Rule to Fire

No RuleFound

Fire Rule

Determine possible rules to

RuleFound

Conditional Elements

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

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

'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

rule "accumulate"

$list : List( intValue > 100 )

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

print "red buses “ + $list;

Accumulate CE

rule "accumulate"

$sum : Number( intValue > 100 )

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

init( sum = 0 ),

action( sum += $t ),

result( sum ) )

print "sum is “ + $sum;

Accumulate CE

rule "accumulate"

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

Accumulate CE

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

rule "collect"

$zipCode : ZipCode()

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

from $hbn.getNamedQuery(“Find Buses”)

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

.list(),

sum( $t ) )

TimersCalendars

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” )

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 , - * /

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

TMS and Inference

rule "Issue Child Bus Pass"

$p : Person( age < 16 )

insert(new ChildBusPass( $p ) );

rule "Issue Adult Bus Pass"

$p : Person( age >= 16 )

insert(new AdultBusPass( $p ) );

Couples the logic

What happens when the Child stops being 16?

TMS and Inference

Bad● Monolithic● Leaky● Brittle integrity - manual maintenance

TMS and Inference

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

retracted.

$p : Person( age < 16 )

logicalInsert( new IsChild( $p ) )

logicalInsert( new IsAdult( $p ) )

de-couples the logic

Maintains the truth by automatically retracting

TMS and Inference

$p : Person( )

IsChild( person =$p )

logicalInsert(new ChildBusPass( $p ) );

rule "Issue Adult Bus Pass"

IsAdult( person =$p )

logicalInsert(new AdultBusPass( $p ) );

The truth maintenance cascades

TMS and Inference

$p : Person( )

not( ChildBusPass( person == $p ) )

requestChildBusPass( $p );

End The truth maintenance cascades

TMS and Inference

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

Tooling

Guided Editor

Interactive Debugging

Decision Tables

Rule Flow

Drools Fusion

$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

$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

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

$c : Custumer( type == “VIP )$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

Operators

$c : Custumer( type == “VIP )$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

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 )

1000 tickers

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

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

Rules and processes

loosely coupledtightly coupled

DecisionServices

ProcessRules

COUPLING

Business Logic Lifecycle

Example

RuleFlowGroup

Workflow can control my rules?

RuleFlowGroup

Rule Flow Group

RuleFlowGroup

Constraints

Java code constraint

Constraints

Rules can control my workflow?

LHS “when”Rule Constraint

Example

Business decisions are externalized using a decision service

rule Decision1 when // conditions then // actionsend

Example

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

rule Decision1 when // conditions then // actionsend

RulesEngine

Flow of Control

ProcessEngine

RulesEngine

Inversion of Control

ProcessEngine

Self monitoring and adaptive

declare ProcessStartedEvent

@role( event )

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) )

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

Domain Specific Processes

Integrated debug and audit

Unified API

DefinitionsRuntime

Language

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);

EPServiceProvider epService = EPServiceProviderManager.getDefaultProvider();

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

countStmt.start();

Definitions

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

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

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' />

<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

Stateful KnowledgeSession

Knowledge Runtime

Coming in 5.1

BPMN2 (80% of Workflow) Integration

● OSGi ready● Spring● Camel

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

Spring + camel

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

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?

Lille2010markp

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

Technology