Drools5 Community Training
DSL & Decision Tables
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Module 6: Drools Expert
DSL & Decision Tables
Drools5 Community Training
version: 1.0-SNAPSHOT
Release Date: 03/16/2011
Under The Creative Common License

Module 6: Drools Expert
DSL & Decision Tables
Drools5 Community Training Course
by Mauricio "Salaboy"
Salatino and Esteban Aliverti is
licensed under a Creative Commons
Attribution 3.0 Unported License.
Based on a work at salaboy.wordpress.
com.
Permissions beyond the scope of this
license may be available at http:
//salaboy.wordpress.com/.

Agenda
● Other ways to express rules
○ Domain Specific Languages
○ Decision Tables

Other ways to express rules
● DSL -> Express Rules in natural Language
● SpreadSheets -> Express rules as decision tables

Domain Specific Languages
Example:
DRL:
Song(genre == "Jazz")
DSL:
[Condition]There is a Jazz Song = Song(genre == "Jazz")

Domain Specific Languages
● Focused on Subject Matter Experts
● Natural Language
● Can be used in guided editor
● It's just mapping your business language in DRL

DSL Example
DSL files have two main sections (condition / consequence) with the
following semantics:
[condition or consequence] natural language expression = drools mapping/execution expression
DSL semantics allow binding of variables in the natural language
expression to the drools expression:
When the user is called {userName} = User(name== "{userName}")
DSL resources must be added to kbuilder previous to DSLR

DSL Full Example
DSL File
DSLR File

Decision Tables
● More business-user friendly
● Useful in situations when we have a lot of similar rules
● Drools supports XLS or CSV files
● Behind-the-scenes Drools transforms Decision Tables to
vanilla DRL

Decision Tables Example

Hands on Labs
Projects:
● 04 :: Drools Expert Spreadsheet Example
● 05 :: Drools Expert DSL Simple Example

Questions?

Enjoy! Questions and Feedback are
always appreciated!

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www.plugtree.com