This document discusses Decision Model and Notation (DMN) and Drools DMN support. It defines DMN as a standard for modeling and executing decision logic. It outlines the components of a DMN solution including decision requirements diagrams, decision tables, and the FEEL expression language. It describes three levels of DMN conformance and provides an example of an end-to-end DMN solution in Drools.

1. Decision Model and Notation (DMN)
and Drools DMN support
Matteo Mortari
Software Engineer
Drools team

2. Decision Model and Notation (DMN)
and Drools DMN support
Agenda:
●
What is DMN
●
Components of a DMN solution
●
Conformance levels and the big picture
●
DEMO: a complete end-to-end DMN solution

3. WHAT IS DMN ?
DMN, which stands for Decision Model and Notation, is a relatively new standard
managed by OMG, the organization behind BPMN. It is trying to do for Business
Decision Management what BPMN did for Business Process Management
a decade ago: empower the business to take charge of the logic that drives its
operations, through a vendor-independent diagramming language.
Bruce Silver, http://methodandstyle.com/what-is-dmn

4. A GRAPHICAL LANGUAGE
FOR DECISION MODELING
including
a standard notation for
Decision Tables
FEEL
EXPRESSION LANGUAGE
Friendly
Enough
Expression
Language
METAMODEL
AND INTERCHANGE
3 levels of conformity
and
XML interchange format
WHAT IS DMN ?
every price in [ 80, 11, 90 ]
satisfies price > 10

5. BRIEF HISTORY
Versions released:
●
1.0 – September 2015
●
Introduced DMN
●
Had several problems (bugs) on both the XML schema definition and the FEEL language that
prevented its full implementation.
●
1.1 – June 2016
●
RTF group worked to fix most of the problems from the version 1.0
●
It is the first version of the spec that is fully implementable (with a few minor issues)
Specification documents at: http://www.omg.org/spec/DMN/

6. COMPONENTS
OF A DMN SOLUTION

7. DMN GRAPHICAL LANGUAGE - EXAMPLE

8. DMN GRAPHICAL LANGUAGE - EXAMPLE
Input Node

9. DMN GRAPHICAL LANGUAGE - EXAMPLE
Input NodeDecision
Node

10. DMN GRAPHICAL LANGUAGE - EXAMPLE
Input NodeDecision
Node

11. DMN GRAPHICAL LANGUAGE - EXAMPLE
Input NodeDecision
Node
Business Knowledge Model

12. DMN GRAPHICAL LANGUAGE - EXAMPLE
Input NodeDecision
Node
Business Knowledge Model

13. DMN GRAPHICAL LANGUAGE - EXAMPLE
Decision Table name
Hit policy
Rule number
Conditions
Result column

14. WHAT IS FEEL?
FEEL, which stands for Friendly Enough Expression Language, is a new expression language
defined by the DMN specification. It aims to bridge the gap between decision modelling and
execution, by assigning semantics to the decision model constructs.
●
Aims to be usable by any user “capable of using Excel formulas”
●
Is used both in DRD (Decision Requirement Diagrams) as well as Decision Tables
●
Two levels of compliance:
●
Level 2: requires only the features of S-FEEL (a simplified FEEL defined in chapter 9 of the
spec)
●
Level 3: require full implementation of FEEL (as defined in chapter 10 of the spec)

15. FEEL EXAMPLE – BOXED EXPRESSION
BKM name
Parameters
BKM result
Expressions
Context entries
(“Local variables”)

16. CONFORMANCE LEVELS
and THE BIG PICTURE

17. CONFORMANCE LEVELs
The spec defines 3 incremental conformance levels for implementations:
CONFORMANCE LEVEL 1
Requires support for authoring of Decision Requirements Diagram, Decision Logic and Decision Tables
This conformance level is basically “documentation only”, no execution required
CONFORMANCE LEVEL 2
Everything from conformance level 1, plus support for the S-FEEL (simplified FEEL) expression language
Requires execution, and requires the logic modeled in CL1 to be expressed in S-FEEL
CONFORMANCE LEVEL 3
Everything from conformance level 2, plus support for the full FEEL language
This includes additional modeling elements like “boxed expressions”

18. DMN TCK: a community effort
https://dmn-tck.github.io/tck

19. DMN: big picture

20. DMN: big picture

21. DMN: big picture

22. DMN: big picture
BPMN
DMN

23. A COMPLETE END-TO-END
DMN SOLUTION

24. MODELING
AUTHORING
DEMO: A COMPLETE END-TO-END SOLUTION
METHODOLOGY
TRAINING
RUNTIME
VALIDATION
DECISION MODEL AND NOTATION (DMN)

25. DEMO !

26. DEMO HIGHLIGHTS

27. DEMO HIGHLIGHTS

28. DEMO HIGHLIGHTS

29. DEMO HIGHLIGHTS

30. DEMO HIGHLIGHTS

31. WHAT’s NEXT

32. SOME POINTERS
Where to get more information:
●
DMN specification: http://www.omg.org/spec/DMN
●
Drools Website: http://drools.org
●
Specific Chapter for Drools DMN support in the documentation
●
DMN quickstart: https://www.trisotech.com/dmnquickstart
●
Bruce Silver’s book: DMN Method & Style : http://methodandstyle.com/books

33. THANK YOU
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