Developing applications with rules, workflow and event processing (it@cork 2010)

Mark Proctor Co-Creator Project Lead
T he 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

Topics
Books
Community
History
Unified Concept
Declarative Domain Overview
Declarative Programming
Domain Overview
The Future
Expert
Quick Example
Conditional Elements
Truth Maintenance and Inference
Fusion
Decision Tables
Guvnor
What's new in 5.1

Books
Introduction to Expert Systems
Peter Jackson
Expert Systems, Principles and Programming
Joseph C. Giarratano and Gary D. Riley

Oh And There are Drools Books Too

Community

Drools Research Network
http://www.jboss.org/drools/research-network.html
30+ Research related pages
Many more as haven't updated

Community Collaboration
40% of Drools work now done in the community
US Navy Healthcare
OSDE (Argentina's largest healthcare organisation)

Standards
Part of the W3C RIF working group
Director in RuleML group

Sample Industries and Users
Investment
Millennium Investment Group (MIG)
Logistics
Fedex
Airline
Sabre
Mortgage
Franklin American
Healthcare
OSDE

Boot Camps
San Francisco 2009 (40+ attendees)
Sponsored by Third Pillar
Sun, FAMC, OSDE, Kaseya, Fedex, TU Group, Intermountain Healthcare, Gap, Sony Pictures, Lockheed Martin, Kaiser, HP, Wells Fargo, US Navy Research, FOLIOfn, Boeing .....
San Diego 2010 (80+ attendess)
Sponsored by US Navy
5 day event, with 2 days focus on the healthcare industry
OSDE, AT&T, SAIC, US Navy Research, Kaiser, Clinica, Intermountain Healthcare, GE Healthcare, VA, Boeing, Nationwide ....

Communication
User and Dev mailing lists
IRC, Internet Relay Chat

History

It All Started Here Birth of CDSS 1970s 1980s Dendral Baobab Mycin Guidon Neomycin Teiresias Puff Emycin WM Sacon Centaur Wheeze Gravida Clot Oncocin

Because Not Everyone Is As Smart As He Is

Business Rules Engines 1980s 2010s 1990s 2000s OPS5 ART Clips Jess Drools 2 JRules Drools 3 Drools 4 Drools 5

Drools History
Drools 2
Rete “like” XML Scripting language
Drools 3
Based on Clips functionality
Iterative improves to JRules syntax with Clips functionality
Drools 4
More declarative
Basic functional programming feature with “from”
Basic Rule Flow
Basic BRMS
Drools 5
Improved functional programming with 'accumulate'
More Advanced Rule Flow integration
Complex Event Process (Fusion)
Temporal Comparators, Sliding Time Windows
Production ready BRMS

Unified Concept

Drools Modules (Also Now Drools Planner)

Business Logic Lifecycle

Rules and processes loosely coupled tightly coupled specific generic Decision Services Process Rules SCOPE COUPLING ?

Achieving More By Doing Less

jBPM File file = new File (“.....”); // file to XML process definition ProcessDefinition processDefinition = ProcessDefinition.parseXmlString( IoUtils.FileToString( file ) ); ProcessInstance processInstance = new ProcessInstance(processDefinition); Jess Rete 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(); Knowledge API

Drools Flow KnowledegBuilder kbuilder = KnowledgeBuilderFactory.newKnowledgeBulider(); kbuilder.addResource( ResourceFactory.newClassPathResource( “myflow.bpmn2”, ResourceType.BPMN2 ); If ( kbuilder.hasErrors() ) { log.error( kbuilder.hasErrors().toString() ); } KnowledgeBase kbase = KnowledgeBaseFactory.newKnowledgeBase(); kbase.addKnowledgePackages( kbase.getKnowledgePackages() ); Knowledge API

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() ); Knowledge API

Drools Integration Deployment Descriptors <change-set> <add> <resource source='classpath:myapp/data/myflow.bpmn2' type='BPMN2' /> <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 ); Knowledge XML

<drools:kbase id="kbase1"> <drools:resource type="DRL" source="classpath:.../testSpring.drl" /> </drools:kbase> <drools:ksession id="ksession1" type=" stateless " kbase ="kbase1" /> <drools:ksession id="ksession2" type=" stateful " kbase ="kbase1"/> <camelContext id="camel"> <route> <from uri="cxfrs://bean://rsServer"/> <marshal ref="xstream"/> <to uri=”drools:ksession1” /> <unmarshal ref="xstream"/> </route> </camelContext> Declarative Services Spring XML and Camel

Stateful Knowledge Session

Knowledge Runtime

Integrated debug and audit

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

Rules and Process Together

Domain Specific Processes

Declarative Domain Overview

Production Rule Systems PRD (forward chaining)
Reactive
when Alarm( status == “alert” ) then send( “warning” )
Logic Programming LP (backward chaining)
Query
descendant( “mary”, “jane”)
Functional Programming FP
Map,Fold, Filter
avg([12, 16, 4, 6])
Returns single value 9.5
round([10.3, 4.7, 7.8] )
Returns List [10, 5, 8]
Description Logic
Person hasName String and livesAt Address

Production Rule Systems PRD (forward chaining FC)
Drools 5.0, OPSJ ( hyrbid BC), ART( hyrbid BC)
Logic Programming LP (backward chaining BC)
target : Prolog (POSL Position Slotted Language)
Drools Trunk has a prototype Prolog like query backward chaining capabilities. Stronger Polog like capabilities planned.
Opportunistic BC planned.
Functional Programming FP
Lisp, Haskell
Drools 5.0 has some functional capabilities
Drools 5.1, 5.2 will be looking to have strong functional capabilities

Description Logic DL
KIF, OWL-DL
Planned, See “The Future”
Processes
Drools 5.1 implements BPMN2 with advanced rule integration.
Drools Flow will be incorporated into jBPM5

Domain Overview

The Future
Full Hybrid Engine
http://community.jboss.org/wiki/DroolsLanguageEnhancements
Nested Objects
Casting Nested Objects
Positional Constraints
POSL - Positional-Slotted Language
Method Calls
Maps and Arrays (Collections)
Collections and XPath like filtering
Free form Expressions
Managed Object Graphs (MOGS)
Nested Patterns and Queries
Queries and Unification
Ontologies and Relations via
Query Based Backward Chaining with POSL
Triples with Hybrid POJO Graph Notation.
Escapes for Dialects
Accumulate Improvements to Support Haskell map/fold/filter and MVEL projection/fold
Otherwise
Branch (Labelled Else)
Rule Execution Groups
Rule Dependency Meta-Rule Language
Parallel Meta-Rule Language
Field Versioning
Logical Closures/OnFalse
Opportunistic Backward Chaining, Lazy Field/Object Values
...

Drools Expert Quick Example Stateless

Definitions public class Applicant { private String name; private int age; private boolean valid; // getter and setter methods here } rule "Is of valid age" when $a : Applicant( age < 18 ) then modify ( $a ) { valid = false }; ends

Building KnowledgeBuilder kbuilder = KnowledgeBuilderFactory .newKnowledgeBuilder(); kbuilder .add( ResourceFactory .newClassPathResource( "licenseApplication.drl" , getClass() ), ResourceType.DRL ); if ( kbuilder .hasErrors() ) { System.err.println( kbuilder .getErrors().toString() ); } kbase .addKnowledgePackages( kbuilder .getKnowledgePackages() );

Executing StatelessKnowledgeSession ksession = kbase .newStatelessKnowledgeSession(); Applicant applicant = new Applicant ( "Mr John Smith" , 16 ); assertTrue ( applicant .isValid() ); ksession .execute( applicant ); assertFalse ( applicant .isValid() ); rule "Is of valid age" when $a : Applicant( age < 18 ) then modify ( $a ) { valid = false }; ends

Drools Expert Quick Example Stateful

Definitions public class Room { private String name // getter and setter methods here } public class Sprinkler { private Room room ; private boolean on ; // getter and setter methods here } public class Fire { private Room room ; // getter and setter methods here } public class Alarm { }

Definitions rule "When there is a fire turn on the sprinkler" when Fire ($room : room) $sprinkler : Sprinkler ( room == $room, on == false ) then modify ( $sprinkler ) { on = true }; println ( "Turn on the sprinkler for room " + $room.name ); end rule "When the fire is gone turn off the sprinkler" when $room : Room ( ) $sprinkler : Sprinkler ( room == $room, on == true ) not Fire ( room == $room ) then modify ( $sprinkler ) { on = false }; println ( "Turn off the sprinkler for room " + $room.name ); end

Definitions rule "Raise the alarm when we have one or more fires" when exists Fire () then insert ( new Alarm () ); println ( "Raise the alarm" ); end rule "Cancel the alarm when all the fires have gone" when not Fire () $alarm : Alarm () then retract ( $alarm ); println ( "Cancel the alarm" ); end

Definitions rule "Status output when things are ok" when not Alarm () not Sprinkler ( on == true ) then println ( "Everything is ok" ); end

Executing String [] names = new String []{ "kitchen" , "bedroom" , "office" , "livingroom" }; Map < String , Room > name2room = new HashMap < String , Room >(); for ( String name : names ){ Room room = new Room ( name ); name2room .put( name , room ); ksession .insert( room ); Sprinkler sprinkler = new Sprinkler ( room ); ksession .insert( sprinkler ); } ksession .fireAllRules() > Everything is ok

Executing Fire kitchenFire = new Fire ( name2room.get( "kitchen" ) ); Fire officeFire = new Fire ( name2room.get( "office" ) ); FactHandle kitchenFireHandle = ksession .insert( kitchenFire ); FactHandle officeFireHandle = ksession .insert( officeFire ); ksession .fireAllRules(); > Raise the alarm > Turn on the sprinkler for room kitchen > Turn on the sprinkler for room office

Executing ksession .retract( kitchenFireHandle ); ksession .retract( officeFireHandle ); ksession .fireAllRules() > Turn off the sprinkler for room office > Turn off the sprinkler for room kitchen > Cancel the alarm > Everything is ok rule "Status output when things are ok" when not Alarm () not Sprinkler ( on == true ) then println ( "Everything is ok" ); end

Conditional Elements

not Bus( color = “red” ) Conditional Elements exists Bus( color = “red” ) forall ( $bus : Bus( floors == 2 ) Bus( this == $bus, color == “red” ) ) forall ( $bus : Bus( color == “red” ) )

Accumulate CE rule "accumulate" when $sum : Number( intValue > 100 ) from accumulate ( Bus( color == "red" , $t : takings ) sum( $t ) ) then print "sum is “ + $sum; end

Accumulate CE Patterns and CE's can be chained with ' from ' rule "collect" when $zipCode : ZipCode() $sum : Number( intValue > 100 ) from accumulate ( Bus( color == "red" , $t : takings ) from $hbn.getNamedQuery( “Find Buses” ) .setParameters( [ “zipCode” : $zipCode ] ) .list(), sum( $t ) ) then print "sum is “ + $sum; end

Timers Calendars

Timers rule “name” timer 1m30s when $l : Light( status == “on” ) then modify ( $l ) { status = “off” }; rule “name” timer (int: 1m30s 0) when $l : Light( status == “on” ) then modify ( $l ) { status = “off” }; When the light is on, and has been on for 1m30s then turn it off Same as above. Interval timer with JDK semantics for initial duration, then repeat duration.

Timers rule “name” timer ( cron: 0 0/15 * * * * ) when Alarm( ) then sendEmail( ”Alert Alert Alert!!!” ) Field Name Mandatory? Allowed Values Allowed Special Characters Seconds YES 0-59 , - * / Minutes YES 0-59 , - * / Hours YES 0-23 , - * / Day of month YES 1-31 , - * ? / L W Month YES 1-12 or JAN-DEC , - * / Day of week YES 1-7 or SUN-SAT , - * ? / L # Year NO empty, 1970-2099 , - * / Send alert every quarter of an hour

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 Execute now and after 1 hour duration Execute now and after 4 hour duration

Drools Expert A Little Deeper

Classes

increase balance for AccountPeriod Credits select * from Account acc, Cashflow cf, AccountPeriod ap where 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 ap where acc.accountNo == cf.accountNo and cf.type == DEBIT cf.date >= ap.start and cf.date <= ap.end trigger : acc.balance += cf.amount trigger : acc.balance -= cf.amount Creating Views with Triggers

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 ap where acc.accountNo == cf.accountNo and cf.type == CREDIT cf.date >= ap.start and cf.date <= ap.end trigger : acc.balance += cf.amount Bringing it Together

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 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”

Truth Maintenance Inference

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?

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.
when $p : Person ( age < 16 ) then logicalInsert ( new IsChild ( $p ) ) end when $p : Person ( age >= 16 ) then logicalInsert ( new IsAdult ( $p ) ) end de-couples the logic Maintains the truth by automatically retracting

TMS and Inference rule "Issue Child Bus Pass" when $p : Person ( ) IsChild ( person =$p ) then logicalInsert ( new ChildBusPass ( $p ) ); end rule "Issue Adult Bus Pass" when $p : Person ( age >= 16 ) IsAdult ( person =$p ) then logicalInsert ( new AdultBusPass ( $p ) ); end The truth maintenance cascades

TMS and Inference rule "Issue Child Bus Pass" when $p : Person ( ) not ( ChildBusPass ( person == $p ) ) then 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

Drools Expert Authoring Metaphores

Guided Editor

Decision Table

Decision Table rule "Pricing bracket_10" when Driver(age >= 18, age <= 24, locationRiskProfile == "LOW", priorClaims == "1") policy: Policy(type == "COMPREHENSIVE") then policy.setBasePrice(450); end

Fusion

Drools Fusion: Enables...
Event Detection:
From an event cloud or set of streams, select all the meaningful events, and only them.
[Temporal] Event Correlation:
Ability to correlate events and facts declaring both temporal and non-temporal constraints between them.
Ability to reason over event aggregation.
Event Sequencing:
A -> ( B OR C ) -> D
Event Abstraction:
Ability to compose complex events from atomic events AND reason over them

Drools Fusion: Features
Support to Event semantics:
Usually immutable, but not enforced
Strong temporal relationships
Managed lifecycle
Point-in-time and Interval events
Time semantics
Discrete
Temporal relationships
All 13 operators defined by James Allen (+ negations)

Drools Fusion: Temporal Reasoning

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

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

Drools Guvnor

Guvnor
Technology
JCR (JSR-170) backend
Seam + GWT frontend
WebDav
Eclipse synchronisation plugin
Role based security
Authoring
Decision Tables
Guided Editor
Rule Templates
Sentence Templates (DSLs)
Declared Types
QA
Scenario Testing
Rule Verification

Business asset storage

Category based browsing

Guided Editor

Decision Tables

Scenario Testing

What's new In 5.1

What's new to 5.1
Integration
OSGi ready
Spring
Camel
JMX/JOPR integration
Expert
New Rete Algorithm “differential update”
Timers and Calendars
Live Open Querries
Flow
BPMN2

Differential Update
Differential Update (a.k.a. “true modify”)
Implements a real “modify/update” operation, instead of retract+assert.
Reuses tuples, reduces GC stress, improves performance

What's new to 5.1
Guvnor
Guided editor
Nested Expression builder
person.dogs[0].name
Move constrains up and down
Insert constraints
Support for more DRL elements
RSS Subcription, change notifications, inbox
Working Sets
Object constraint definitions
Rule Templates (based on Guided Editor)
Oryx BPM editor integration
Better rule documentation support

Drools flow in Oryx

Drools flow in Eclipse

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?

Developing applications with rules, workflow and event processing (it@cork 2010)

by Geoffrey De Smet

Accessibility

Categories

Upload Details

Usage Rights

Statistics

Developing applications with rules, workflow and event processing (it@cork 2010) Presentation Transcript