Merge branch 'master' of https://github.com/JonCook/tutorials

drools/README.MD

@@ -0,0 +1,9 @@
+## Drools
+
+This module contains articles about Drools
+
+### Relevant Articles:
+
+- [Introduction to Drools](https://www.baeldung.com/drools)
+- [Drools Using Rules from Excel Files](https://www.baeldung.com/drools-excel)
+- [An Example of Backward Chaining in Drools](https://www.baeldung.com/drools-backward-chaining)

drools/pom.xml

@@ -0,0 +1,66 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<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>
+    <artifactId>drools</artifactId>
+    <name>drools</name>
+    
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-spring-4</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
+        <relativePath>../parent-spring-4</relativePath>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.apache.httpcomponents</groupId>
+            <artifactId>httpcore</artifactId>
+            <version>${http-component-version}</version>
+        </dependency>
+        <!-- ... -->
+        <dependency>
+            <groupId>org.kie</groupId>
+            <artifactId>kie-ci</artifactId>
+            <version>${drools-version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.drools</groupId>
+            <artifactId>drools-decisiontables</artifactId>
+            <version>${drools-version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.drools</groupId>
+            <artifactId>drools-core</artifactId>
+            <version>${drools-version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.drools</groupId>
+            <artifactId>drools-compiler</artifactId>
+            <version>${drools-version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.poi</groupId>
+            <artifactId>poi</artifactId>
+            <version>${apache-poi-version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.poi</groupId>
+            <artifactId>poi-ooxml</artifactId>
+            <version>${apache-poi-version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.optaplanner</groupId>
+            <artifactId>optaplanner-core</artifactId>
+            <version>${opta-planner-version}</version>
+        </dependency>
+    </dependencies>
+
+    <properties>
+        <http-component-version>4.4.6</http-component-version>
+        <drools-version>7.4.1.Final</drools-version>
+        <apache-poi-version>3.13</apache-poi-version>
+        <opta-planner-version>7.10.0.Final</opta-planner-version>
+    </properties>
+
+</project>

drools/src/main/java/com/baeldung/drools/backward_chaining/BackwardChaining.java

@@ -0,0 +1,30 @@
+package com.baeldung.drools.backward_chaining;
+
+import org.kie.api.runtime.KieSession;
+
+import com.baeldung.drools.config.DroolsBeanFactory;
+import com.baeldung.drools.model.Fact;
+import com.baeldung.drools.model.Result;
+
+public class BackwardChaining {
+    public static void main(String[] args) {
+        Result result = new BackwardChaining().backwardChaining();
+        System.out.println(result.getValue());
+        result.getFacts()
+            .stream()
+            .forEach(System.out::println);
+    }
+
+    public Result backwardChaining() {
+        Result result = new Result();
+        KieSession ksession = new DroolsBeanFactory().getKieSession();
+        ksession.setGlobal("result", result);
+        ksession.insert(new Fact("Asia", "Planet Earth"));
+        ksession.insert(new Fact("China", "Asia"));
+        ksession.insert(new Fact("Great Wall of China", "China"));
+
+        ksession.fireAllRules();
+
+        return result;
+    }
+}

drools/src/main/java/com/baeldung/drools/config/DroolsBeanFactory.java

@@ -0,0 +1,108 @@
+package com.baeldung.drools.config;
+
+import org.drools.decisiontable.DecisionTableProviderImpl;
+import org.kie.api.KieServices;
+import org.kie.api.builder.*;
+import org.kie.api.io.Resource;
+import org.kie.api.runtime.KieContainer;
+import org.kie.api.runtime.KieSession;
+import org.kie.internal.builder.DecisionTableConfiguration;
+import org.kie.internal.builder.DecisionTableInputType;
+import org.kie.internal.builder.KnowledgeBuilderFactory;
+import org.kie.internal.io.ResourceFactory;
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.List;
+
+public class DroolsBeanFactory {
+
+    private static final String RULES_PATH = "com/baeldung/drools/rules/";
+    private KieServices kieServices=KieServices.Factory.get();
+
+    private  KieFileSystem getKieFileSystem() throws IOException{
+        KieFileSystem kieFileSystem = kieServices.newKieFileSystem();
+        List<String> rules=Arrays.asList("BackwardChaining.drl","SuggestApplicant.drl","Product_rules.xls");
+        for(String rule:rules){
+            kieFileSystem.write(ResourceFactory.newClassPathResource(rule));
+        }
+        return kieFileSystem;
+
+    }
+
+    public KieContainer getKieContainer() throws IOException {
+        getKieRepository();
+
+        KieBuilder kb = kieServices.newKieBuilder(getKieFileSystem());
+        kb.buildAll();
+
+        KieModule kieModule = kb.getKieModule();
+        KieContainer kContainer = kieServices.newKieContainer(kieModule.getReleaseId());
+
+        return kContainer;
+
+    }
+
+    private void getKieRepository() {
+        final KieRepository kieRepository = kieServices.getRepository();
+        kieRepository.addKieModule(new KieModule() {
+                        public ReleaseId getReleaseId() {
+                return kieRepository.getDefaultReleaseId();
+            }
+        });
+    }
+
+    public KieSession getKieSession(){
+        getKieRepository();
+        KieFileSystem kieFileSystem = kieServices.newKieFileSystem();
+
+        kieFileSystem.write(ResourceFactory.newClassPathResource("com/baeldung/drools/rules/BackwardChaining.drl"));
+        kieFileSystem.write(ResourceFactory.newClassPathResource("com/baeldung/drools/rules/SuggestApplicant.drl"));
+        kieFileSystem.write(ResourceFactory.newClassPathResource("com/baeldung/drools/rules/Product_rules.xls"));
+        
+        
+        KieBuilder kb = kieServices.newKieBuilder(kieFileSystem);
+        kb.buildAll();
+        KieModule kieModule = kb.getKieModule();
+
+        KieContainer kContainer = kieServices.newKieContainer(kieModule.getReleaseId());
+
+        return kContainer.newKieSession();
+
+    }
+
+    public KieSession getKieSession(Resource dt) {
+        KieFileSystem kieFileSystem = kieServices.newKieFileSystem()
+            .write(dt);
+
+        KieBuilder kieBuilder = kieServices.newKieBuilder(kieFileSystem)
+            .buildAll();
+
+        KieRepository kieRepository = kieServices.getRepository();
+
+        ReleaseId krDefaultReleaseId = kieRepository.getDefaultReleaseId();
+
+        KieContainer kieContainer = kieServices.newKieContainer(krDefaultReleaseId);
+
+        KieSession ksession = kieContainer.newKieSession();
+
+        return ksession;
+    }
+
+    /*
+     * Can be used for debugging
+     * Input excelFile example: com/baeldung/drools/rules/Discount.xls
+     */
+    public String getDrlFromExcel(String excelFile) {
+        DecisionTableConfiguration configuration = KnowledgeBuilderFactory.newDecisionTableConfiguration();
+        configuration.setInputType(DecisionTableInputType.XLS);
+
+        Resource dt = ResourceFactory.newClassPathResource(excelFile, getClass());
+
+        DecisionTableProviderImpl decisionTableProvider = new DecisionTableProviderImpl();
+
+        String drl = decisionTableProvider.loadFromResource(dt, null);
+
+        return drl;
+    }
+
+}

drools/src/main/java/com/baeldung/drools/model/Applicant.java

@@ -0,0 +1,48 @@
+package com.baeldung.drools.model;
+
+public class Applicant {
+
+    private String name;
+    private int age;
+    private double currentSalary;
+    private int experienceInYears;
+
+    public Applicant(String name, int age, Double currentSalary, int experienceInYears) {
+        this.name = name;
+        this.age = age;
+        this.currentSalary = currentSalary;
+        this.experienceInYears = experienceInYears;
+    }
+
+    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;
+    }
+
+    public Double getCurrentSalary() {
+        return currentSalary;
+    }
+
+    public void setCurrentSalary(Double currentSalary) {
+        this.currentSalary = currentSalary;
+    }
+
+    public int getExperienceInYears() {
+        return experienceInYears;
+    }
+
+    public void setExperienceInYears(int experienceInYears) {
+        this.experienceInYears = experienceInYears;
+    }
+}

drools/src/main/java/com/baeldung/drools/model/Customer.java

@@ -0,0 +1,44 @@
+package com.baeldung.drools.model;
+
+public class Customer {
+
+    private CustomerType type;
+
+    private int years;
+
+    private int discount;
+
+    public Customer(CustomerType type, int numOfYears) {
+        super();
+        this.type = type;
+        this.years = numOfYears;
+    }
+
+    public CustomerType getType() {
+        return type;
+    }
+
+    public void setType(CustomerType type) {
+        this.type = type;
+    }
+
+    public int getYears() {
+        return years;
+    }
+
+    public void setYears(int years) {
+        this.years = years;
+    }
+
+    public int getDiscount() {
+        return discount;
+    }
+
+    public void setDiscount(int discount) {
+        this.discount = discount;
+    }
+
+    public enum CustomerType {
+        INDIVIDUAL, BUSINESS;
+    }
+}

drools/src/main/java/com/baeldung/drools/model/Fact.java

@@ -0,0 +1,69 @@
+package com.baeldung.drools.model;
+
+import org.kie.api.definition.type.Position;
+
+public class Fact {
+
+    @Position(0)
+    private String element;
+
+    @Position(1)
+    private String place;
+
+    public Fact(String element, String place) {
+        this.element = element;
+        this.place = place;
+    }
+
+    public String getElement() {
+        return element;
+    }
+
+    public void setElement(String element) {
+        this.element = element;
+    }
+
+    public String getPlace() {
+        return place;
+    }
+
+    public void setPlace(String place) {
+        this.place = place;
+    }
+
+    @Override
+    public int hashCode() {
+        final int prime = 31;
+        int result = 1;
+        result = prime * result + ((element == null) ? 0 : element.hashCode());
+        result = prime * result + ((place == null) ? 0 : place.hashCode());
+        return result;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj)
+            return true;
+        if (obj == null)
+            return false;
+        if (getClass() != obj.getClass())
+            return false;
+        Fact other = (Fact) obj;
+        if (element == null) {
+            if (other.element != null)
+                return false;
+        } else if (!element.equals(other.element))
+            return false;
+        if (place == null) {
+            if (other.place != null)
+                return false;
+        } else if (!place.equals(other.place))
+            return false;
+        return true;
+    }
+
+    @Override
+    public String toString() {
+        return "Fact{" + "element='" + element + '\'' + ", place='" + place + '\'' + '}';
+    }
+}

drools/src/main/java/com/baeldung/drools/model/Product.java

@@ -0,0 +1,38 @@
+package com.baeldung.drools.model;
+
+public class Product {
+    private String name;
+    private String type;
+
+    private String label;
+
+    public Product(String name, String type) {
+        this.name = name;
+        this.type = type;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getType() {
+        return type;
+    }
+
+    public void setType(String type) {
+        this.type = type;
+    }
+
+    public String getLabel() {
+        return label;
+    }
+
+    public void setLabel(String label) {
+        this.label = label;
+    }
+
+}

drools/src/main/java/com/baeldung/drools/model/Result.java

@@ -0,0 +1,31 @@
+package com.baeldung.drools.model;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class Result {
+    private String value;
+    private List<String> facts = new ArrayList<>();
+
+    public String getValue() {
+        return value;
+    }
+
+    public void setValue(String value) {
+        this.value = value;
+    }
+
+    public List<String> getFacts() {
+        return facts;
+    }
+
+    public void setFacts(List<String> facts) {
+        this.facts = facts;
+    }
+    
+    public void addFact(String fact) {
+        this.facts.add(fact);
+    }
+    
+    
+}

drools/src/main/java/com/baeldung/drools/model/SuggestedRole.java

@@ -0,0 +1,14 @@
+package com.baeldung.drools.model;
+
+public class SuggestedRole {
+
+    private String role;
+
+    public String getRole() {
+        return role;
+    }
+
+    public void setRole(String role) {
+        this.role = role;
+    }
+}

drools/src/main/java/com/baeldung/drools/optaplanner/CourseSchedule.java

@@ -0,0 +1,63 @@
+package com.baeldung.drools.optaplanner;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.optaplanner.core.api.domain.solution.PlanningEntityCollectionProperty;
+import org.optaplanner.core.api.domain.solution.PlanningScore;
+import org.optaplanner.core.api.domain.solution.PlanningSolution;
+import org.optaplanner.core.api.domain.solution.drools.ProblemFactCollectionProperty;
+import org.optaplanner.core.api.domain.valuerange.ValueRangeProvider;
+import org.optaplanner.core.api.score.buildin.hardsoft.HardSoftScore;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+@PlanningSolution
+public class CourseSchedule {
+
+    Logger logger = LoggerFactory.getLogger("CourseSchedule");
+
+    private List<Integer> roomList;
+    private List<Integer> periodList;
+    private List<Lecture> lectureList;
+    private HardSoftScore score;
+
+    public CourseSchedule(){
+        roomList = new ArrayList<>();
+        periodList = new ArrayList<>();
+        lectureList = new ArrayList<>();
+    }
+
+    @ValueRangeProvider(id = "availableRooms")
+    @ProblemFactCollectionProperty
+    public List<Integer> getRoomList() {
+        return roomList;
+    }
+
+    @ValueRangeProvider(id = "availablePeriods")
+    @ProblemFactCollectionProperty
+    public List<Integer> getPeriodList() {
+        return periodList;
+    }
+
+    @PlanningEntityCollectionProperty
+    public List<Lecture> getLectureList() {
+        return lectureList;
+    }
+
+    @PlanningScore
+    public HardSoftScore getScore() {
+        return score;
+    }
+
+    public void setScore(HardSoftScore score) {
+        this.score = score;
+    }
+
+    public void printCourseSchedule() {
+        lectureList.stream()
+                .map(c -> "Lecture in Room " + c.getRoomNumber().toString() + " during Period " + c.getPeriod().toString())
+                .forEach(k -> logger.info(k));
+    }
+
+}

drools/src/main/java/com/baeldung/drools/optaplanner/Lecture.java

@@ -0,0 +1,30 @@
+package com.baeldung.drools.optaplanner;
+
+import org.optaplanner.core.api.domain.entity.PlanningEntity;
+import org.optaplanner.core.api.domain.variable.PlanningVariable;
+
+@PlanningEntity
+public class Lecture {
+
+    private Integer roomNumber;
+    private Integer period;
+
+    @PlanningVariable(valueRangeProviderRefs = {"availablePeriods"})
+    public Integer getPeriod() {
+        return period;
+    }
+
+    @PlanningVariable(valueRangeProviderRefs = {"availableRooms"})
+    public Integer getRoomNumber() {
+        return roomNumber;
+    }
+
+    public void setPeriod(Integer period) {
+        this.period = period;
+    }
+
+    public void setRoomNumber(Integer roomNumber) {
+        this.roomNumber = roomNumber;
+    }
+
+}

drools/src/main/java/com/baeldung/drools/optaplanner/ScoreCalculator.java

@@ -0,0 +1,32 @@
+package com.baeldung.drools.optaplanner;
+
+import java.util.HashSet;
+
+import org.optaplanner.core.api.score.Score;
+import org.optaplanner.core.api.score.buildin.hardsoft.HardSoftScore;
+import org.optaplanner.core.impl.score.director.easy.EasyScoreCalculator;
+
+public class ScoreCalculator implements EasyScoreCalculator<CourseSchedule> {
+
+    @Override
+    public Score calculateScore(CourseSchedule courseSchedule) {
+        int hardScore = 0;
+        int softScore = 0;
+
+        HashSet<String> occupiedRooms = new HashSet<>();
+        for (Lecture lecture : courseSchedule.getLectureList()) {
+            if(lecture.getPeriod() != null && lecture.getRoomNumber() != null) {
+                String roomInUse = lecture.getPeriod().toString() + ":" + lecture.getRoomNumber().toString();
+                if (occupiedRooms.contains(roomInUse)) {
+                    hardScore += -1;
+                } else {
+                    occupiedRooms.add(roomInUse);
+                }
+            } else {
+                hardScore += -1;
+            }
+        }
+
+        return HardSoftScore.valueOf(hardScore, softScore);
+    }
+}

drools/src/main/java/com/baeldung/drools/service/ApplicantService.java

@@ -0,0 +1,23 @@
+package com.baeldung.drools.service;
+
+import com.baeldung.drools.config.DroolsBeanFactory;
+import com.baeldung.drools.model.Applicant;
+import com.baeldung.drools.model.SuggestedRole;
+import org.kie.api.runtime.KieContainer;
+import org.kie.api.runtime.KieSession;
+
+import java.io.IOException;
+
+public class ApplicantService {
+
+    KieSession kieSession=new DroolsBeanFactory().getKieSession();
+
+    public SuggestedRole suggestARoleForApplicant(Applicant applicant,SuggestedRole suggestedRole) throws IOException {
+        kieSession.insert(applicant);
+        kieSession.setGlobal("suggestedRole",suggestedRole);
+        kieSession.fireAllRules();
+        System.out.println(suggestedRole.getRole());
+        return  suggestedRole;
+
+    }
+}

drools/src/main/java/com/baeldung/drools/service/ProductService.java

@@ -0,0 +1,20 @@
+package com.baeldung.drools.service;
+
+import com.baeldung.drools.config.DroolsBeanFactory;
+import com.baeldung.drools.model.Product;
+import org.kie.api.runtime.KieContainer;
+import org.kie.api.runtime.KieSession;
+
+public class ProductService {
+
+    private KieSession kieSession=new DroolsBeanFactory().getKieSession();
+
+    public Product applyLabelToProduct(Product product){
+        kieSession.insert(product);
+        kieSession.fireAllRules();
+        System.out.println(product.getLabel());
+        return  product;
+
+    }
+
+}

drools/src/main/resources/com/baeldung/drools/rules/BackwardChaining.drl

@@ -0,0 +1,27 @@
+package com.baeldung.drools.rules
+
+import com.baeldung.drools.model.Fact;
+
+global com.baeldung.drools.model.Result result;
+
+dialect  "mvel"
+
+query belongsTo(String x, String y)
+  Fact(x, y;)
+  or
+  (Fact(z, y;) and belongsTo(x, z;))
+end
+
+rule "Great Wall of China BELONGS TO Planet Earth"
+when
+    belongsTo("Great Wall of China", "Planet Earth";)
+then
+	result.setValue("Decision one taken: Great Wall of China BELONGS TO Planet Earth");
+end
+
+rule "print all facts"
+when
+    belongsTo(element, place;)
+then
+    result.addFact(element + " IS ELEMENT OF " + place);
+end

drools/src/main/resources/com/baeldung/drools/rules/SuggestApplicant.drl

@@ -0,0 +1,31 @@
+package com.baeldung.drools.rules;
+
+import com.baeldung.drools.model.Applicant;
+
+global com.baeldung.drools.model.SuggestedRole suggestedRole;
+
+dialect  "mvel"
+
+rule "Suggest Manager Role"
+    when
+        Applicant(experienceInYears > 10)
+        Applicant(currentSalary > 1000000 && currentSalary <= 2500000)
+    then
+        suggestedRole.setRole("Manager");
+end
+
+rule "Suggest Senior developer Role"
+    when
+        Applicant(experienceInYears > 5 && experienceInYears <= 10)
+        Applicant(currentSalary > 500000 && currentSalary <= 1500000)
+    then
+        suggestedRole.setRole("Senior developer");
+end
+
+rule "Suggest Developer Role"
+    when
+        Applicant(experienceInYears > 0 && experienceInYears <= 5)
+        Applicant(currentSalary > 200000 && currentSalary <= 1000000)
+    then
+        suggestedRole.setRole("Developer");
+end

drools/src/main/resources/courseSchedule.drl

@@ -0,0 +1,14 @@
+package com.baeldung.drools.optaplanner
+
+import com.baeldung.drools.optaplanner.Lecture;
+import org.optaplanner.core.api.score.buildin.hardsoft.HardSoftScoreHolder;
+
+global HardSoftScoreHolder scoreHolder;
+
+rule "noNullRoomPeriod"
+    when
+        Lecture( roomNumber == null );
+        Lecture( period == null );
+    then
+        scoreHolder.addHardConstraintMatch(kcontext, -1);
+end

drools/src/main/resources/courseScheduleSolverConfigDrools.xml

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<solver>
+    <scanAnnotatedClasses/>
+
+    <scoreDirectorFactory>
+        <scoreDrl>courseSchedule.drl</scoreDrl>
+    </scoreDirectorFactory>
+
+    <termination>
+        <secondsSpentLimit>10</secondsSpentLimit>
+    </termination>
+</solver>

drools/src/main/resources/courseScheduleSolverConfiguration.xml

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<solver>
+    <scanAnnotatedClasses/>
+
+    <scoreDirectorFactory>
+        <easyScoreCalculatorClass>com.baeldung.drools.optaplanner.ScoreCalculator</easyScoreCalculatorClass>
+    </scoreDirectorFactory>
+
+    <termination>
+        <secondsSpentLimit>10</secondsSpentLimit>
+    </termination>
+</solver>

drools/src/main/resources/logback.xml

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<configuration>
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n
+            </pattern>
+        </encoder>
+    </appender>
+
+    <root level="INFO">
+        <appender-ref ref="STDOUT" />
+    </root>
+</configuration>

drools/src/test/java/com/baeldung/drools/backward_chaining/BackwardChainingIntegrationTest.java

@@ -0,0 +1,36 @@
+package com.baeldung.drools.backward_chaining;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.kie.api.runtime.KieSession;
+
+import com.baeldung.drools.config.DroolsBeanFactory;
+import com.baeldung.drools.model.Fact;
+import com.baeldung.drools.model.Result;
+
+import static junit.framework.TestCase.assertEquals;
+
+public class BackwardChainingIntegrationTest {
+    private Result result;
+    private KieSession ksession;
+ 
+    @Before
+    public void before() {
+        result = new Result();
+        ksession = new DroolsBeanFactory().getKieSession();
+    }
+
+    @Test
+    public void whenWallOfChinaIsGiven_ThenItBelongsToPlanetEarth() {
+
+        ksession.setGlobal("result", result);
+        ksession.insert(new Fact("Asia", "Planet Earth"));
+        ksession.insert(new Fact("China", "Asia"));
+        ksession.insert(new Fact("Great Wall of China", "China"));
+
+        ksession.fireAllRules();
+        
+        // Assert Decision one
+        assertEquals(result.getValue(), "Decision one taken: Great Wall of China BELONGS TO Planet Earth");
+    }
+}

drools/src/test/java/com/baeldung/drools/optaplanner/OptaPlannerUnitTest.java

@@ -0,0 +1,49 @@
+package com.baeldung.drools.optaplanner;
+
+import java.util.Arrays;
+
+import org.junit.Assert;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+import org.optaplanner.core.api.solver.Solver;
+import org.optaplanner.core.api.solver.SolverFactory;
+
+public class OptaPlannerUnitTest {
+
+    static CourseSchedule unsolvedCourseSchedule;
+
+    @BeforeAll
+    public static void setUp() {
+
+        unsolvedCourseSchedule = new CourseSchedule();
+
+        for(int i = 0; i < 10; i++){
+            unsolvedCourseSchedule.getLectureList().add(new Lecture());
+        }
+
+        unsolvedCourseSchedule.getPeriodList().addAll(Arrays.asList(new Integer[] { 1, 2, 3 }));
+        unsolvedCourseSchedule.getRoomList().addAll(Arrays.asList(new Integer[] { 1, 2 }));
+    }
+
+    @Test
+    public void test_whenCustomJavaSolver() {
+
+        SolverFactory<CourseSchedule> solverFactory = SolverFactory.createFromXmlResource("courseScheduleSolverConfiguration.xml");
+        Solver<CourseSchedule> solver = solverFactory.buildSolver();
+        CourseSchedule solvedCourseSchedule = solver.solve(unsolvedCourseSchedule);
+
+        Assert.assertNotNull(solvedCourseSchedule.getScore());
+        Assert.assertEquals(-4, solvedCourseSchedule.getScore().getHardScore());
+    }
+
+    @Test
+    public void test_whenDroolsSolver() {
+
+        SolverFactory<CourseSchedule> solverFactory = SolverFactory.createFromXmlResource("courseScheduleSolverConfigDrools.xml");
+        Solver<CourseSchedule> solver = solverFactory.buildSolver();
+        CourseSchedule solvedCourseSchedule = solver.solve(unsolvedCourseSchedule);
+
+        Assert.assertNotNull(solvedCourseSchedule.getScore());
+        Assert.assertEquals(0, solvedCourseSchedule.getScore().getHardScore());
+    }
+}

drools/src/test/java/com/baeldung/drools/service/ApplicantServiceIntegrationTest.java

@@ -0,0 +1,55 @@
+package com.baeldung.drools.service;
+
+import com.baeldung.drools.model.Applicant;
+import com.baeldung.drools.model.SuggestedRole;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.io.IOException;
+
+import static junit.framework.Assert.assertNull;
+import static junit.framework.TestCase.assertEquals;
+
+
+public class ApplicantServiceIntegrationTest {
+
+
+    private ApplicantService applicantService;
+
+    @Before
+    public void setup() {
+        applicantService = new ApplicantService();
+    }
+
+    @Test
+    public void whenCriteriaMatching_ThenSuggestManagerRole() throws IOException {
+        Applicant applicant = new Applicant("Davis", 37, 1600000.0, 11);
+        SuggestedRole suggestedRole = new SuggestedRole();
+        applicantService.suggestARoleForApplicant(applicant, suggestedRole);
+        assertEquals("Manager", suggestedRole.getRole());
+    }
+
+    @Test
+    public void whenCriteriaMatching_ThenSuggestSeniorDeveloperRole() throws IOException {
+        Applicant applicant = new Applicant("John", 37, 1200000.0, 8);
+        SuggestedRole suggestedRole = new SuggestedRole();
+        applicantService.suggestARoleForApplicant(applicant, suggestedRole);
+        assertEquals("Senior developer", suggestedRole.getRole());
+    }
+
+    @Test
+    public void whenCriteriaMatching_ThenSuggestDeveloperRole() throws IOException {
+        Applicant applicant = new Applicant("Davis", 37, 800000.0, 3);
+        SuggestedRole suggestedRole = new SuggestedRole();
+        applicantService.suggestARoleForApplicant(applicant, suggestedRole);
+        assertEquals("Developer", suggestedRole.getRole());
+    }
+
+    @Test
+    public void whenCriteriaNotMatching_ThenNoRole() throws IOException {
+        Applicant applicant = new Applicant("John", 37, 1200000.0, 5);
+        SuggestedRole suggestedRole = new SuggestedRole();
+        applicantService.suggestARoleForApplicant(applicant, suggestedRole);
+        assertNull(suggestedRole.getRole());
+    }
+}

drools/src/test/java/com/baeldung/drools/service/DiscountExcelIntegrationTest.java

@@ -0,0 +1,56 @@
+package com.baeldung.drools.service;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.kie.api.io.Resource;
+import org.kie.api.runtime.KieSession;
+import org.kie.internal.io.ResourceFactory;
+
+import com.baeldung.drools.config.DroolsBeanFactory;
+import com.baeldung.drools.model.Customer;
+import com.baeldung.drools.model.Customer.CustomerType;
+
+public class DiscountExcelIntegrationTest {
+
+    private KieSession kSession;
+
+    @Before
+    public void setup() {
+        Resource resource = ResourceFactory.newClassPathResource("com/baeldung/drools/rules/Discount.xls", getClass());
+        kSession = new DroolsBeanFactory().getKieSession(resource);
+    }
+
+    @Test
+    public void giveIndvidualLongStanding_whenFireRule_thenCorrectDiscount() throws Exception {
+        Customer customer = new Customer(CustomerType.INDIVIDUAL, 5);
+        kSession.insert(customer);
+
+        kSession.fireAllRules();
+
+        assertEquals(customer.getDiscount(), 15);
+    }
+
+    @Test
+    public void giveIndvidualRecent_whenFireRule_thenCorrectDiscount() throws Exception {
+
+        Customer customer = new Customer(CustomerType.INDIVIDUAL, 1);
+        kSession.insert(customer);
+
+        kSession.fireAllRules();
+
+        assertEquals(customer.getDiscount(), 5);
+    }
+
+    @Test
+    public void giveBusinessAny_whenFireRule_thenCorrectDiscount() throws Exception {
+        Customer customer = new Customer(CustomerType.BUSINESS, 0);
+        kSession.insert(customer);
+
+        kSession.fireAllRules();
+
+        assertEquals(customer.getDiscount(), 20);
+    }
+
+}

drools/src/test/java/com/baeldung/drools/service/ProductServiceIntegrationTest.java

@@ -0,0 +1,33 @@
+package com.baeldung.drools.service;
+
+import com.baeldung.drools.model.Product;
+import org.junit.Before;
+import org.junit.Test;
+
+import static junit.framework.TestCase.assertEquals;
+
+
+public class ProductServiceIntegrationTest {
+
+    private ProductService productService;
+
+    @Before
+    public void setup() {
+        productService = new ProductService();
+    }
+
+
+    @Test
+    public void whenProductTypeElectronic_ThenLabelBarcode() {
+        Product product = new Product("Microwave", "Electronic");
+        product = productService.applyLabelToProduct(product);
+        assertEquals("BarCode", product.getLabel());
+    }
+
+    @Test
+    public void whenProductTypeBook_ThenLabelIsbn() {
+        Product product = new Product("AutoBiography", "Book");
+        product = productService.applyLabelToProduct(product);
+        assertEquals("ISBN", product.getLabel());
+    }
+}