feat(kotlin): Kotlinify domain classes to remove boilerplate code

Author: ge0ffrey

technology/kotlin-quarkus/src/main/kotlin/org/acme/kotlin/schooltimetabling/domain/Lesson.kt

@@ -7,14 +7,12 @@ import com.fasterxml.jackson.annotation.JsonIdentityReference
 
 
 @PlanningEntity
-class Lesson {
-
+data class Lesson (
     @PlanningId
-    var id: Long? = null
-
-    lateinit var subject: String
-    lateinit var teacher: String
-    lateinit var studentGroup: String
+    val id: Long,
+    val subject: String,
+    val teacher: String,
+    val studentGroup: String) {
 
     @JsonIdentityReference
     @PlanningVariable
@@ -24,23 +22,15 @@ class Lesson {
     @PlanningVariable
     var room: Room? = null
 
-    // No-arg constructor required for Hibernate and Timefold
-    constructor()
+    // No-arg constructor required for Timefold
+    constructor() : this(0, "", "", "")
 
-    constructor(id: Long?, subject: String, teacher: String, studentGroup: String) {
-        this.id = id
-        this.subject = subject.trim()
-        this.teacher = teacher.trim()
-        this.studentGroup = studentGroup.trim()
-    }
-
-    constructor(id: Long?, subject: String, teacher: String, studentGroup: String, timeslot: Timeslot?, room: Room?)
+    constructor(id: Long, subject: String, teacher: String, studentGroup: String, timeslot: Timeslot?, room: Room?)
             : this(id, subject, teacher, studentGroup) {
         this.timeslot = timeslot
         this.room = room
     }
 
-
     override fun toString(): String = "$subject($id)"
 
 }

technology/kotlin-quarkus/src/main/kotlin/org/acme/kotlin/schooltimetabling/domain/Room.kt

@@ -9,20 +9,10 @@ import com.fasterxml.jackson.annotation.ObjectIdGenerators
     generator = ObjectIdGenerators.PropertyGenerator::class,
     property = "id"
 )
-class Room {
-
+data class Room(
     @PlanningId
-    var id: Long? = null
-
-    lateinit var name: String
-
-    // No-arg constructor required for Hibernate
-    constructor()
-
-    constructor(id: Long?, name: String) {
-        this.id = id
-        this.name = name
-    }
+    val id: Long,
+    val name: String) {
 
     override fun toString(): String = name
 

technology/kotlin-quarkus/src/main/kotlin/org/acme/kotlin/schooltimetabling/domain/Timeslot.kt

@@ -11,27 +11,12 @@ import java.time.LocalTime
     generator = ObjectIdGenerators.PropertyGenerator::class,
     property = "id"
 )
-class Timeslot {
-
+data class Timeslot(
     @PlanningId
-    var id: Long? = null
-
-    lateinit var dayOfWeek: DayOfWeek
-    lateinit var startTime: LocalTime
-    lateinit var endTime: LocalTime
-
-    // No-arg constructor required for Hibernate
-    constructor()
-
-    constructor(id: Long?, dayOfWeek: DayOfWeek, startTime: LocalTime, endTime: LocalTime) {
-        this.id = id
-        this.dayOfWeek = dayOfWeek
-        this.startTime = startTime
-        this.endTime = endTime
-    }
-
-    constructor(id: Long?, dayOfWeek: DayOfWeek, startTime: LocalTime) :
-            this(id, dayOfWeek, startTime, startTime.plusMinutes(50))
+    val id: Long,
+    val dayOfWeek: DayOfWeek,
+    val startTime: LocalTime,
+    val endTime: LocalTime = startTime.plusMinutes(50)) {
 
     override fun toString(): String = "$dayOfWeek $startTime"
 

technology/kotlin-quarkus/src/main/kotlin/org/acme/kotlin/schooltimetabling/domain/Timetable.kt

@@ -9,43 +9,27 @@ import ai.timefold.solver.core.api.score.buildin.hardsoft.HardSoftScore
 import ai.timefold.solver.core.api.solver.SolverStatus
 
 @PlanningSolution
-class Timetable {
-
-    lateinit var name: String
-
+data class Timetable (
+    val name: String,
     @ProblemFactCollectionProperty
     @ValueRangeProvider
-    lateinit var timeslots: List<Timeslot>
-
+    val timeslots: List<Timeslot>,
     @ProblemFactCollectionProperty
     @ValueRangeProvider
-    lateinit var rooms: List<Room>
-
+    val rooms: List<Room>,
     @PlanningEntityCollectionProperty
-    lateinit var lessons: List<Lesson>
-
+    val lessons: List<Lesson>,
     @PlanningScore
-    var score: HardSoftScore? = null
-
+    var score: HardSoftScore? = null,
     // Ignored by Timefold, used by the UI to display solve or stop solving button
-    var solverStatus: SolverStatus? = null
+    var solverStatus: SolverStatus? = null) {
 
     // No-arg constructor required for Timefold
-    constructor() {}
+    constructor() : this("", emptyList(), emptyList(), emptyList())
+
+    constructor(name: String, score: HardSoftScore?, solverStatus: SolverStatus)
+            : this(name, emptyList(), emptyList(), emptyList(), score, solverStatus)
 
-    constructor(name: String, score: HardSoftScore?, solverStatus: SolverStatus) {
-        this.name = name
-        this.score = score
-        this.solverStatus = solverStatus
-        this.timeslots = emptyList()
-        this.rooms = emptyList()
-        this.lessons = emptyList()
-    }
+    override fun toString(): String = name
 
-    constructor(name: String, timeslots: List<Timeslot>, rooms: List<Room>, lessons: List<Lesson>) {
-        this.name = name
-        this.timeslots = timeslots
-        this.rooms = rooms
-        this.lessons = lessons
-    }
 }