13.6. 创建并运行 school timetable 应用程序

流程

1. 创建 src/main/java/org/acme/schooltimetabling/TimeTableApp.java 类：

   package org.acme.schooltimetabling;
   
   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.acme.schooltimetabling.domain.Lesson;
   import org.acme.schooltimetabling.domain.Room;
   import org.acme.schooltimetabling.domain.TimeTable;
   import org.acme.schooltimetabling.domain.Timeslot;
   import org.acme.schooltimetabling.solver.TimeTableConstraintProvider;
   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;
   
   public 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 data set.
                   // It's recommended to run for at least 5 minutes ("5m") otherwise.
                   .withTerminationSpentLimit(Duration.ofSeconds(10)));
   
           // 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());
               }
           }
       }
   
   }

2. 运行 TimeTableApp 类作为普通 Java 应用程序的主要类。以下输出应结果：

   ...
   INFO  |            | Room A     | Room B     | Room C     |
   INFO  |------------|------------|------------|------------|
   INFO  | MON 08:30  | English    | Math       |            |
   INFO  |            | I. Jones   | A. Turing  |            |
   INFO  |            | 9th grade  | 10th grade |            |
   INFO  |------------|------------|------------|------------|
   INFO  | MON 09:30  | History    | Physics    |            |
   INFO  |            | I. Jones   | M. Curie   |            |
   INFO  |            | 9th grade  | 10th grade |            |
   ...

3. 验证控制台输出。它是否符合所有硬约束？如果您在 TimeTableConstraintProvider 中注释掉 roomConflict 约束，会发生什么？