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![Units
package org.mypackage.myunit
public class AdultUnit implements RuleUnit {
private int adultAge;
private DataSource<Person> persons;
public AdultUnit( ) { }
public AdultUnit( DataSource<Person> persons, int age ) {
this.persons = persons;
this.age = age;
}
}
package org.mypackage.myunit
unit AdultUnit
rule Adult when
$p : /persons[age >= adultAge]
then
System.out.println($p.getName() +
" is adult and greater than " +
adultAge);
end](https://image.slidesharecdn.com/aike2019markp-190603154357/85/Rule-Modularity-and-Execution-Control-27-320.jpg)
![Units package org.mypackage.myunit
unit AdultUnit
rule Adult when
$p : /persons[age >= adultAge]
then
System.out.println($p.getName() +
" is adult and greater than " +
adultAge);
end
package org.mypackage.myunit
public class AdultUnit implements RuleUnit {
private int adultAge;
private DataSource<Person> persons;
public AdultUnit( ) { }
public AdultUnit( DataSource<Person> persons, int age ) {
this.persons = persons;
this.age = age;
}
@Override
public boolean onStart(RuleUnitInstance instance) {
System.out.println(getName() + " started.”);
return true;
}
@Override
public boolean onEnd(RuleUnitInstance instance) {
return true;
}
}](https://image.slidesharecdn.com/aike2019markp-190603154357/85/Rule-Modularity-and-Execution-Control-28-320.jpg)
Uploaded byMark Proctor
Rule Modularity and Execution Control
This document discusses the history and evolution of production rule systems from the 1970s to present. It covers early systems like OPS5 and CLIPS and how they introduced concepts like the Rete algorithm, modules, and object-oriented features. It then summarizes more recent systems like Drools and Jess. The document also proposes approaches for improving rule modularity and execution control, such as using rule units and life cycle annotations to better orchestrate rule firing. Overall it presents the continuing development of production rule technologies and opportunities for further modernization.
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Rule Modularity and Execution Control
- 1. Mark Proctor Distinguished EngineerII Chief Architect - Rules, BPM and Optimisation Red Hat Modernising Production Rule Systems Rule Modularity and Execution Control
- 2.
- 3. OPS OPS5 1981 •Language •Rete •LEX/MEA (p mb17 (goal^status active ^type on ^object <o>) (object ^name <o> ^at <p>) (monkey ^at <p> ^holds nil) --> (write (crlf) "climb onto" <o>) (modify 3 ^on <o>) (modify 1 ^status satisfied)) OPS •Official Production System. •pre OPS5 linear Search. •Conflict Resolution <McDermott, Forgy 1976>. Working Memory Rules Inference Engine Pattern Matching Agenda
- 4. CLIPS CLIPS 1993 •Lisp (ish) •exists/forall •Subnetworks •Modules •SimpleTMS (defrule climb-directly "" ?goal <- (goal-is-to (action on) (arguments ?obj)) (thing (name ?obj) (location ?place) (on-top-of ?on)) ?monkey <- (monkey (location ?place) (on-top-of ?on) (holding blank)) => (printout t "Monkey climbs onto the " ?obj "." crlf) (modify ?monkey (on-top-of ?obj)) (retract ?goal)) CLIPS •Syntax based on ART (Haley Systems) •Modules based on GoldWorks •PIE Clips Modules Working Memory Modules Inference Engine Pattern Matching Agenda
- 5. Jess Jess7 2006 •Accumulate •Slot Specific •BackwardChaining (ish) (deftemplate employee (slot salary) (slot name)) (defrule count-highly-paid-employees ?c <- (accumulate (bind ?count 0) ;; initializer (bind ?count (+ ?count 1)) ;; action ?count ;; result (employee (salary ?s&:(> ?s 100000)))) ;; CE => (printout t ?c " employees make more than $100000/year." crlf)) Jess •Java implementation of Clips syntax Working Memory Modules Inference Engine Pattern Matching Agenda
- 6. Drools Drools 6.x/7.x 2018 •Accumulate •TemporalOperators •Property Reactive •Prolog(ish) Backward Chaining •OOPath Graph Reasoning Drools •Clips/Jess derivative with Java-like language Working Memory Modules Inference Engine Pattern Matching Agenda
- 7. Slow Progress Is StillProgress
- 8. Still Here Working Memory Modules Inference Engine PatternMatching Agenda
- 9. Still Here Working Memory Modules InferenceEngine Pattern Matching Agenda “Today, I want to make clear that the future prospects for production rule technology are diminishing..… production rule technology is inadequate ” (Paul Haley 2013) http://haleyai.com/wordpress/2013/06/22/confessions-of-a-production-rule-vendor-part-1/
- 10. Still Here Working Memory Modules InferenceEngine Pattern Matching Agenda “Today, I want to make clear that the future prospects for production rule technology are diminishing..… production rule technology is inadequate” (Paul Haley 2013) http://haleyai.com/wordpress/2013/06/22/confessions-of-a-production-rule-vendor-part-1/
- 11. Still Here Working Memory Modules InferenceEngine Pattern Matching Agenda “It’s time to trade rule technology dating back to the 80’s for state of the art AI.” (Paul Haley 2018) • http://haleyai.com/wordpress/2018/04/02/confessions-of-a-production-rule-vendor-part-2/
- 12. Still Here Working MemoryModules InferenceEngine Pattern Matching Agenda
- 13.
- 14.
- 15. • Production systemconflict resolution strategies (McDermott, Forgy 1976) • Conflict Resolution + Control Token (Signals, GOTO) • Mixes Control and Domain Logic in single rule • This Pollution may be undesirable for readability and maintainability • Does not guarantee rules for one token have fired before processing another token • OPS MEA (Forgy 1981) • Compares recency for the first pattern to find the dominant rule. • Typically matches against a fact called a Context, Phase or Goal. • Allows for goal-directed controlling of production systems which also introduces a type of rule subroutine. • Compares recency for the remaining elements • LEX falls back on specificity and arbitrary. Stylistic
- 16. • ROSIE (D.A. Waterman, 1979) • Multiple data sets and rule sets. • Only one ruleset and one data set can be active at a time. • Eclips (NASA, 1991) PIE (NASA, 1988) • Goal directed. • Each goal has a context. • Subroutine like. • Clips Modules (NASA 1993) • Push/Pop Stack • No Context • External Orchestration • Rule Flow Syntactic
- 17.
- 18. • Rules anddata are decoupled. • Venus full hybrid C++ language. • Single Root Module. • Guard does not directly invoke Rule. Instead it makes it legible for evaluation. • Current consequence finishes, before potential next module is entered. • Module may have 1..n Support. Will continue to evaluate, while it has support. • If support is removed, module continues until it reaches fixed point (then it’s removed). • Is single threaded a fair deterministic policy is used to help with selection, which is controlled by the priority of the rule against its peers. • Submitted module is identified by the combination of module name plus the passed arguments. Venus Rule Language
- 19.
- 20.
- 21. • ENTRY-BLOCK • C-callableentry block • Can have their own rules • Implicitly activate • May activate one or more rule Rule-Blocks • RULE-BLOCK • Allow for rules to be shared across ENTRY-BLOCKs • May not call other ENTRY-BLOCKs or RULE-BLOCKs. • External Orchestration Rule Works
- 22. • ON-ENTRY: Beforethe match step of the first recognize- act cycle. This can be used for tasks like data initialisation. • ON-EVERY: After the act step of every cycle except the last one. This can be used for tasks like printing out the rule count. • ON-EMPTY: After the select step when the conflict set is empty. This can be used to detect state and return error information. • ON-EXIT: After the act step of the last cycle. This can be used for things like cleanup actions. Rule Works
- 23. Rule Works LifeCycles ON-ENTRY ON-EVERY Match Act Select ON-EMPTY ON-EXIT Call to Entry Block Operating System Caller of Entry Block
- 24. • Neither Venusor RuleWorks made it into industrial or academic mainstream. • Business Rules have simple requirements. • Often spreadsheet driven. • Variations Rule Flow suffices. • Academia is funding driven, interests change over time. Recency and Relevance of Works
- 25.
- 26. Units package org.mypackage.myunit public classAdultUnit implements RuleUnit { private int adultAge; private DataSource<Person> persons; public AdultUnit( ) { } public AdultUnit( DataSource<Person> persons, int age ) { this.persons = persons; this.age = age; } }
- 27. Units package org.mypackage.myunit public classAdultUnit implements RuleUnit { private int adultAge; private DataSource<Person> persons; public AdultUnit( ) { } public AdultUnit( DataSource<Person> persons, int age ) { this.persons = persons; this.age = age; } } package org.mypackage.myunit unit AdultUnit rule Adult when $p : /persons[age >= adultAge] then System.out.println($p.getName() + " is adult and greater than " + adultAge); end
- 28. Units package org.mypackage.myunit unitAdultUnit rule Adult when $p : /persons[age >= adultAge] then System.out.println($p.getName() + " is adult and greater than " + adultAge); end package org.mypackage.myunit public class AdultUnit implements RuleUnit { private int adultAge; private DataSource<Person> persons; public AdultUnit( ) { } public AdultUnit( DataSource<Person> persons, int age ) { this.persons = persons; this.age = age; } @Override public boolean onStart(RuleUnitInstance instance) { System.out.println(getName() + " started.”); return true; } @Override public boolean onEnd(RuleUnitInstance instance) { return true; } }
- 29. Recommendation and BiddingExample
- 30. Recommendation and BiddingExample
- 31. Recommendation and BiddingExample
- 32. • PENDING: Theunit is instantiated, but has not yet been started. • RUNNING: The unit is evaluating and executing rules. • DORMANT: The unit has either reached a fixed point and has no more work to evaluate, or it has been requested to stop further evaluation. • YIELDED: The current executing unit has yielded (while still having more work to do) to another unit that has earlier scheduling. States
- 33. Unit Life Cycles RUNNINGDORMANTYIELDED start true resume true yield true onSuspend suspend true onResume onStart onEnd onYield onResume PENDING FINISHED RuleUnitInstance Created CANCELLED start false resume true resume false suspend false yeld false resume false resume request resume request suspend request yield request start request ON-ENTRY ON-EVERY Match Act Select ON-EMPTY ON-EXIT Call to Entry Block Operating System Caller of Entry Block
- 34. • @Yield(<boolean>) • @TerminateOnEmpty AdditionalControl via Annotations
- 35. • Depth firstLIFO. • Where the two guards exist for the same unit, the one that comes earlier in the rule order has priority. • Where the two guards are not from the same unit, but the path of one subsumes the path of the other, the deepest unit has priority. • Where the two guards are not from the same unit and one path does not subsume the other, it will iterate the parent chain until it reaches the unit that is shared by both Fairness
- 36. • Units asgeneric abstractions for runtimes • Execution guards • On every • Inheritance • Alternative orchestrations • Refinements in rule execution • @DataDriven / @Existence Driven • @Incremental(<boolean>) • @Sequential Future Works
- 37.
- 38. Mark Proctor Distinguished EngineerII Chief Architect - Rules, BPM and Optimisation Red Hat Modernising Production Rule Systems Rule Modularity and Execution Control