Creating the Project
- Open Eclipse
- New -> Maven Project (simple project)
- Simple Project
- Group Id: com.skills421.examples.drools
- Artifact Id: Drools6.xDecisionTableExample
- Finish
Structure
pom.xml
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<!-- This Project -->
<groupId>com.skills421.examples.drools</groupId>
<artifactId>Drools6.xDecisionTableExample</artifactId>
<version>0.0.1-SNAPSHOT</version>
<!-- Properties -->
<properties>
<!-- Drools -->
<drools.version>6.3.0.Final</drools.version>
<!-- JUnit -->
<junit.version>4.12</junit.version>
<!-- maven-compiler-plugin -->
<maven.compiler.target>1.8</maven.compiler.target>
<maven.compiler.source>1.8</maven.compiler.source>
</properties>
<!-- Dependencies -->
<dependencies>
<!-- https://mvnrepository.com/artifact/org.drools/drools-core -->
<dependency>
<groupId>org.drools</groupId>
<artifactId>drools-core</artifactId>
<version>${drools.version}</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.drools/drools-compiler -->
<dependency>
<groupId>org.drools</groupId>
<artifactId>drools-compiler</artifactId>
<version>${drools.version}</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.drools/drools-compiler -->
<dependency>
<groupId>org.drools</groupId>
<artifactId>drools-decisiontables</artifactId>
<version>${drools.version}</version>
</dependency>
<!-- https://mvnrepository.com/artifact/junit/junit -->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>${junit.version}</version>
</dependency>
</dependencies>
</project>
Facts
Fact.java
package com.skills421.examples.drools.facts;
public interface Fact
{
}
Person.java
package com.skills421.examples.drools.facts;
public class Person implements Fact
{
private String country;
private String name;
private int age;
public Person()
{
}
public Person(String country,String name, int age)
{
this.country = country;
this.name = name;
this.age = age;
}
public String getCountry()
{
return country;
}
public void setCountry(String country)
{
this.country = country;
}
public String getName()
{
return name;
}
public void setName(String name)
{
this.name = name;
}
public int getAge()
{
return age;
}
public void setAge(int age)
{
this.age = age;
}
@Override
public String toString()
{
return String.format("Person [country=%s, name=%s, age=%s]", country,
name, age);
}
}
RuleResponse.java
package com.skills421.examples.drools.facts;
import java.util.ArrayList;
import java.util.List;
public class RuleResponse implements Fact
{
private List<String> messages = new ArrayList<>();
public List<String> getMessages()
{
return messages;
}
public void setMessages(List<String> messages)
{
this.messages = messages;
}
public void addMessage(String message)
{
this.messages.add(message);
}
}
RuleRunner
RuleRunnerException.java
package com.skills421.examples.drools.exceptions;
public class RuleRunnerException extends Exception
{
private static final long serialVersionUID = 1L;
public RuleRunnerException()
{
super();
}
public RuleRunnerException(String message, Throwable cause,
boolean enableSuppression, boolean writableStackTrace)
{
super(message, cause, enableSuppression, writableStackTrace);
}
public RuleRunnerException(String message, Throwable cause)
{
super(message, cause);
}
public RuleRunnerException(String message)
{
super(message);
}
public RuleRunnerException(Throwable cause)
{
super(cause);
}
}
RuleRunner.java
package com.skills421.examples.drools.controller;
import java.util.ArrayList;
import java.util.List;
import org.kie.api.KieServices;
import org.kie.api.runtime.KieContainer;
import org.kie.api.runtime.KieSession;
import com.skills421.examples.drools.exceptions.RuleRunnerException;
import com.skills421.examples.drools.facts.Fact;
import com.skills421.examples.drools.facts.RuleResponse;
public class RuleRunner
{
private List<Fact> facts = new ArrayList<>();
public RuleRunner()
{
}
public RuleRunner insertFact(Fact fact)
{
facts.add(fact);
return this;
}
public RuleResponse runRules(String ruleset) throws RuleRunnerException
{
RuleResponse response = null;
try
{
KieServices ks = KieServices.Factory.get();
KieContainer kContainer = ks.getKieClasspathContainer();
KieSession kSession = kContainer.newKieSession(ruleset);
for (Fact fact : facts)
{
System.out.println("Inserting: "+fact);
kSession.insert(fact);
}
kSession.fireAllRules();
for (Object fact : kSession.getObjects())
{
if (fact instanceof RuleResponse)
{
response = (RuleResponse) fact;
}
}
}
catch (Exception ex)
{
ex.printStackTrace();
}
return response;
}
}
Rules
Setup.drl
package com.skills421.examples.drools.people
import com.skills421.examples.drools.facts.RuleResponse
dialect "mvel"
/*
* This rule checks for a RuleResponse fact
*/
rule "Ensure Response Object"
when
not RuleResponse()
then
System.out.println("Inserting response");
insert(new RuleResponse());
end
DrinkingRules.xls
drinkingrules
Main
Main.java
package com.skills421.examples.drools;
import com.skills421.examples.drools.controller.RuleRunner;
import com.skills421.examples.drools.exceptions.RuleRunnerException;
import com.skills421.examples.drools.facts.Person;
import com.skills421.examples.drools.facts.RuleResponse;
public class Main
{
public static void main(String[] args) throws RuleRunnerException
{
RuleRunner runner = new RuleRunner();
RuleResponse response = runner
.insertFact(new Person("USA","Jon Doe",21))
.insertFact(new Person("USA","Jane Doe",19))
.insertFact(new Person("UK","Mick Doe",19))
.runRules("people-rules");
for(String message : response.getMessages())
{
System.out.println(message);
}
}
}
kmodule.xml
kmodule.xml
<?xml version="1.0" encoding="UTF-8"?> <kmodule xmlns="http://jboss.org/kie/6.0.0/kmodule"> <kbase name="test" packages="com.skills421.examples.drools.people"> <ksession name="people-rules"/> </kbase> </kmodule>
Output
Inserting: Person [country=USA, name=Jon Doe, age=21] Inserting: Person [country=USA, name=Jane Doe, age=19] Inserting: Person [country=UK, name=Mick Doe, age=19] Inserting response Jon Doe is old enough to drink in their own country (USA) Mick Doe is old enough to drink in their own country (UK) Jon Doe is old enough to drink in the USA Jon Doe is old enough to drink in the UK Jane Doe is old enough to drink in the UK Mick Doe is old enough to drink in the UK
Skills421 