JBang OptaPlanner Hello world issue reproducer

///usr/bin/env jbang "$0" "$@" ; exit $?
//DEPS org.optaplanner:optaplanner-core:8.14.0.Final

import java.time.DayOfWeek;
import java.time.Duration;
import java.time.LocalTime;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;

import org.optaplanner.core.api.domain.entity.PlanningEntity;
import org.optaplanner.core.api.domain.lookup.PlanningId;
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.ProblemFactCollectionProperty;
import org.optaplanner.core.api.domain.valuerange.ValueRangeProvider;
import org.optaplanner.core.api.domain.variable.PlanningVariable;
import org.optaplanner.core.api.score.buildin.hardsoft.HardSoftScore;
import org.optaplanner.core.api.score.stream.Constraint;
import org.optaplanner.core.api.score.stream.ConstraintFactory;
import org.optaplanner.core.api.score.stream.ConstraintProvider;
import org.optaplanner.core.api.score.stream.Joiners;
import org.optaplanner.core.api.solver.Solver;
import org.optaplanner.core.api.solver.SolverFactory;
import org.optaplanner.core.config.solver.SolverConfig;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

class TimeTableApp {

    private static final Logger LOGGER = LoggerFactory.getLogger(TimeTableApp.class);

    public static void main(String[] args) {
        SolverFactory<TimeTable> solverFactory = SolverFactory.create(new SolverConfig()
                .withSolutionClass(TimeTable.class)
                .withEntityClasses(Lesson.class)
                .withConstraintProviderClass(TimeTableConstraintProvider.class)
                // The solver runs only for 5 seconds on this small dataset.
                // It's recommended to run for at least 5 minutes ("5m") otherwise.
                .withTerminationSpentLimit(Duration.ofSeconds(5)));

        // Load the problem
        TimeTable problem = generateDemoData();

        // Solve the problem
        Solver<TimeTable> solver = solverFactory.buildSolver();
        TimeTable solution = solver.solve(problem);

        // Visualize the solution
        printTimetable(solution);
    }

    public static TimeTable generateDemoData() {
        List<Timeslot> timeslotList = new ArrayList<>(10);
        timeslotList.add(new Timeslot(DayOfWeek.MONDAY, LocalTime.of(8, 30), LocalTime.of(9, 30)));
        timeslotList.add(new Timeslot(DayOfWeek.MONDAY, LocalTime.of(9, 30), LocalTime.of(10, 30)));
        timeslotList.add(new Timeslot(DayOfWeek.MONDAY, LocalTime.of(10, 30), LocalTime.of(11, 30)));
        timeslotList.add(new Timeslot(DayOfWeek.MONDAY, LocalTime.of(13, 30), LocalTime.of(14, 30)));
        timeslotList.add(new Timeslot(DayOfWeek.MONDAY, LocalTime.of(14, 30), LocalTime.of(15, 30)));

        timeslotList.add(new Timeslot(DayOfWeek.TUESDAY, LocalTime.of(8, 30), LocalTime.of(9, 30)));
        timeslotList.add(new Timeslot(DayOfWeek.TUESDAY, LocalTime.of(9, 30), LocalTime.of(10, 30)));
        timeslotList.add(new Timeslot(DayOfWeek.TUESDAY, LocalTime.of(10, 30), LocalTime.of(11, 30)));
        timeslotList.add(new Timeslot(DayOfWeek.TUESDAY, LocalTime.of(13, 30), LocalTime.of(14, 30)));
        timeslotList.add(new Timeslot(DayOfWeek.TUESDAY, LocalTime.of(14, 30), LocalTime.of(15, 30)));

        List<Room> roomList = new ArrayList<>(3);
        roomList.add(new Room("Room A"));
        roomList.add(new Room("Room B"));
        roomList.add(new Room("Room C"));

        List<Lesson> lessonList = new ArrayList<>();
        long id = 0;
        lessonList.add(new Lesson(id++, "Math", "A. Turing", "9th grade"));
        lessonList.add(new Lesson(id++, "Math", "A. Turing", "9th grade"));
        lessonList.add(new Lesson(id++, "Physics", "M. Curie", "9th grade"));
        lessonList.add(new Lesson(id++, "Chemistry", "M. Curie", "9th grade"));
        lessonList.add(new Lesson(id++, "Biology", "C. Darwin", "9th grade"));
        lessonList.add(new Lesson(id++, "History", "I. Jones", "9th grade"));
        lessonList.add(new Lesson(id++, "English", "I. Jones", "9th grade"));
        lessonList.add(new Lesson(id++, "English", "I. Jones", "9th grade"));
        lessonList.add(new Lesson(id++, "Spanish", "P. Cruz", "9th grade"));
        lessonList.add(new Lesson(id++, "Spanish", "P. Cruz", "9th grade"));

        lessonList.add(new Lesson(id++, "Math", "A. Turing", "10th grade"));
        lessonList.add(new Lesson(id++, "Math", "A. Turing", "10th grade"));
        lessonList.add(new Lesson(id++, "Math", "A. Turing", "10th grade"));
        lessonList.add(new Lesson(id++, "Physics", "M. Curie", "10th grade"));
        lessonList.add(new Lesson(id++, "Chemistry", "M. Curie", "10th grade"));
        lessonList.add(new Lesson(id++, "French", "M. Curie", "10th grade"));
        lessonList.add(new Lesson(id++, "Geography", "C. Darwin", "10th grade"));
        lessonList.add(new Lesson(id++, "History", "I. Jones", "10th grade"));
        lessonList.add(new Lesson(id++, "English", "P. Cruz", "10th grade"));
        lessonList.add(new Lesson(id++, "Spanish", "P. Cruz", "10th grade"));

        return new TimeTable(timeslotList, roomList, lessonList);
    }

    private static void printTimetable(TimeTable timeTable) {
        LOGGER.info("");
        List<Room> roomList = timeTable.getRoomList();
        List<Lesson> lessonList = timeTable.getLessonList();
        Map<Timeslot, Map<Room, List<Lesson>>> lessonMap = lessonList.stream()
                .filter(lesson -> lesson.getTimeslot() != null && lesson.getRoom() != null)
                .collect(Collectors.groupingBy(Lesson::getTimeslot, Collectors.groupingBy(Lesson::getRoom)));
        LOGGER.info("|            | " + roomList.stream()
                .map(room -> String.format("%-10s", room.getName())).collect(Collectors.joining(" | ")) + " |");
        LOGGER.info("|" + "------------|".repeat(roomList.size() + 1));
        for (Timeslot timeslot : timeTable.getTimeslotList()) {
            List<List<Lesson>> cellList = roomList.stream()
                    .map(room -> {
                        Map<Room, List<Lesson>> byRoomMap = lessonMap.get(timeslot);
                        if (byRoomMap == null) {
                            return Collections.<Lesson>emptyList();
                        }
                        List<Lesson> cellLessonList = byRoomMap.get(room);
                        if (cellLessonList == null) {
                            return Collections.<Lesson>emptyList();
                        }
                        return cellLessonList;
                    })
                    .collect(Collectors.toList());

            LOGGER.info("| " + String.format("%-10s",
                    timeslot.getDayOfWeek().toString().substring(0, 3) + " " + timeslot.getStartTime()) + " | "
                    + cellList.stream().map(cellLessonList -> String.format("%-10s",
                            cellLessonList.stream().map(Lesson::getSubject).collect(Collectors.joining(", "))))
                            .collect(Collectors.joining(" | "))
                    + " |");
            LOGGER.info("|            | "
                    + cellList.stream().map(cellLessonList -> String.format("%-10s",
                            cellLessonList.stream().map(Lesson::getTeacher).collect(Collectors.joining(", "))))
                            .collect(Collectors.joining(" | "))
                    + " |");
            LOGGER.info("|            | "
                    + cellList.stream().map(cellLessonList -> String.format("%-10s",
                            cellLessonList.stream().map(Lesson::getStudentGroup).collect(Collectors.joining(", "))))
                            .collect(Collectors.joining(" | "))
                    + " |");
            LOGGER.info("|" + "------------|".repeat(roomList.size() + 1));
        }
        List<Lesson> unassignedLessons = lessonList.stream()
                .filter(lesson -> lesson.getTimeslot() == null || lesson.getRoom() == null)
                .collect(Collectors.toList());
        if (!unassignedLessons.isEmpty()) {
            LOGGER.info("");
            LOGGER.info("Unassigned lessons");
            for (Lesson lesson : unassignedLessons) {
                LOGGER.info("  " + lesson.getSubject() + " - " + lesson.getTeacher() + " - " + lesson.getStudentGroup());
            }
        }
    }

}

@PlanningSolution
class TimeTable {

    @ProblemFactCollectionProperty
    @ValueRangeProvider(id = "timeslotRange")
    private List<Timeslot> timeslotList;
    @ProblemFactCollectionProperty
    @ValueRangeProvider(id = "roomRange")
    private List<Room> roomList;
    @PlanningEntityCollectionProperty
    private List<Lesson> lessonList;

    @PlanningScore
    private HardSoftScore score;

    // No-arg constructor required for OptaPlanner
    public TimeTable() {
    }

    public TimeTable(List<Timeslot> timeslotList, List<Room> roomList, List<Lesson> lessonList) {
        this.timeslotList = timeslotList;
        this.roomList = roomList;
        this.lessonList = lessonList;
    }

    // ************************************************************************
    // Getters and setters
    // ************************************************************************

    public List<Timeslot> getTimeslotList() {
        return timeslotList;
    }

    public List<Room> getRoomList() {
        return roomList;
    }

    public List<Lesson> getLessonList() {
        return lessonList;
    }

    public HardSoftScore getScore() {
        return score;
    }

}

class Timeslot {

    private DayOfWeek dayOfWeek;
    private LocalTime startTime;
    private LocalTime endTime;

    public Timeslot(DayOfWeek dayOfWeek, LocalTime startTime, LocalTime endTime) {
        this.dayOfWeek = dayOfWeek;
        this.startTime = startTime;
        this.endTime = endTime;
    }

    public Timeslot(DayOfWeek dayOfWeek, LocalTime startTime) {
        this(dayOfWeek, startTime, startTime.plusMinutes(50));
    }

    @Override
    public String toString() {
        return dayOfWeek + " " + startTime;
    }

    // ************************************************************************
    // Getters and setters
    // ************************************************************************

    public DayOfWeek getDayOfWeek() {
        return dayOfWeek;
    }

    public LocalTime getStartTime() {
        return startTime;
    }

    public LocalTime getEndTime() {
        return endTime;
    }

}

class Room {

    private String name;

    public Room(String name) {
        this.name = name;
    }

    @Override
    public String toString() {
        return name;
    }

    // ************************************************************************
    // Getters and setters
    // ************************************************************************

    public String getName() {
        return name;
    }

}

@PlanningEntity
class Lesson {

    @PlanningId
    private Long id;

    private String subject;
    private String teacher;
    private String studentGroup;

    @PlanningVariable(valueRangeProviderRefs = "timeslotRange")
    private Timeslot timeslot;
    @PlanningVariable(valueRangeProviderRefs = "roomRange")
    private Room room;

    // No-arg constructor required for OptaPlanner
    public Lesson() {
    }

    public Lesson(long id, String subject, String teacher, String studentGroup) {
        this.id = id;
        this.subject = subject;
        this.teacher = teacher;
        this.studentGroup = studentGroup;
    }

    public Lesson(long id, String subject, String teacher, String studentGroup, Timeslot timeslot, Room room) {
        this(id, subject, teacher, studentGroup);
        this.timeslot = timeslot;
        this.room = room;
    }

    @Override
    public String toString() {
        return subject + "(" + id + ")";
    }

    // ************************************************************************
    // Getters and setters
    // ************************************************************************

    public Long getId() {
        return id;
    }

    public String getSubject() {
        return subject;
    }

    public String getTeacher() {
        return teacher;
    }

    public String getStudentGroup() {
        return studentGroup;
    }

    public Timeslot getTimeslot() {
        return timeslot;
    }

    public void setTimeslot(Timeslot timeslot) {
        this.timeslot = timeslot;
    }

    public Room getRoom() {
        return room;
    }

    public void setRoom(Room room) {
        this.room = room;
    }

}

class TimeTableConstraintProvider implements ConstraintProvider {

    @Override
    public Constraint[] defineConstraints(ConstraintFactory constraintFactory) {
        return new Constraint[] {
                // Hard constraints
                roomConflict(constraintFactory),
                teacherConflict(constraintFactory),
                studentGroupConflict(constraintFactory),
                // Soft constraints
                teacherRoomStability(constraintFactory),
                teacherTimeEfficiency(constraintFactory),
                studentGroupSubjectVariety(constraintFactory)
        };
    }

    Constraint roomConflict(ConstraintFactory constraintFactory) {
        // A room can accommodate at most one lesson at the same time.
        return constraintFactory
                // Select each pair of 2 different lessons ...
                .forEachUniquePair(Lesson.class,
                        // ... in the same timeslot ...
                        Joiners.equal(Lesson::getTimeslot),
                        // ... in the same room ...
                        Joiners.equal(Lesson::getRoom))
                // ... and penalize each pair with a hard weight.
                .penalize("Room conflict", HardSoftScore.ONE_HARD);
    }

    Constraint teacherConflict(ConstraintFactory constraintFactory) {
        // A teacher can teach at most one lesson at the same time.
        return constraintFactory
                .forEachUniquePair(Lesson.class,
                        Joiners.equal(Lesson::getTimeslot),
                        Joiners.equal(Lesson::getTeacher))
                .penalize("Teacher conflict", HardSoftScore.ONE_HARD);
    }

    Constraint studentGroupConflict(ConstraintFactory constraintFactory) {
        // A student can attend at most one lesson at the same time.
        return constraintFactory
                .forEachUniquePair(Lesson.class,
                        Joiners.equal(Lesson::getTimeslot),
                        Joiners.equal(Lesson::getStudentGroup))
                .penalize("Student group conflict", HardSoftScore.ONE_HARD);
    }

    Constraint teacherRoomStability(ConstraintFactory constraintFactory) {
        // A teacher prefers to teach in a single room.
        return constraintFactory
                .forEachUniquePair(Lesson.class,
                        Joiners.equal(Lesson::getTeacher))
                .filter((lesson1, lesson2) -> lesson1.getRoom() != lesson2.getRoom())
                .penalize("Teacher room stability", HardSoftScore.ONE_SOFT);
    }

    Constraint teacherTimeEfficiency(ConstraintFactory constraintFactory) {
        // A teacher prefers to teach sequential lessons and dislikes gaps between lessons.
        return constraintFactory
                .forEach(Lesson.class)
                .join(Lesson.class, Joiners.equal(Lesson::getTeacher),
                        Joiners.equal((lesson) -> lesson.getTimeslot().getDayOfWeek()))
                .filter((lesson1, lesson2) -> {
                    Duration between = Duration.between(lesson1.getTimeslot().getEndTime(),
                            lesson2.getTimeslot().getStartTime());
                    return !between.isNegative() && between.compareTo(Duration.ofMinutes(30)) <= 0;
                })
                .reward("Teacher time efficiency", HardSoftScore.ONE_SOFT);
    }

    Constraint studentGroupSubjectVariety(ConstraintFactory constraintFactory) {
        // A student group dislikes sequential lessons on the same subject.
        return constraintFactory
                .forEach(Lesson.class)
                .join(Lesson.class,
                        Joiners.equal(Lesson::getSubject),
                        Joiners.equal(Lesson::getStudentGroup),
                        Joiners.equal((lesson) -> lesson.getTimeslot().getDayOfWeek()))
                .filter((lesson1, lesson2) -> {
                    Duration between = Duration.between(lesson1.getTimeslot().getEndTime(),
                            lesson2.getTimeslot().getStartTime());
                    return !between.isNegative() && between.compareTo(Duration.ofMinutes(30)) <= 0;
                })
                .penalize("Student group subject variety", HardSoftScore.ONE_SOFT);
    }

}