18.2. 对域对象建模

流程

1. 创建 src/main/java/com/example/domain/Timeslot.java 类：

   package com.example.domain;
   
   import java.time.DayOfWeek;
   import java.time.LocalTime;
   
   public class Timeslot {
   
       private DayOfWeek dayOfWeek;
       private LocalTime startTime;
       private LocalTime endTime;
   
       private Timeslot() {
       }
   
       public Timeslot(DayOfWeek dayOfWeek, LocalTime startTime, LocalTime endTime) {
           this.dayOfWeek = dayOfWeek;
           this.startTime = startTime;
           this.endTime = endTime;
       }
   
       @Override
       public String toString() {
           return dayOfWeek + " " + startTime.toString();
       }
   
       // ********************************
       // Getters and setters
       // ********************************
   
       public DayOfWeek getDayOfWeek() {
           return dayOfWeek;
       }
   
       public LocalTime getStartTime() {
           return startTime;
       }
   
       public LocalTime getEndTime() {
           return endTime;
       }
   
   }

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   注意 toString （） 方法保持输出短，以便更轻松地阅读 OptaPlanner 的 DEBUG 或 TRACE 日志，如稍后所示。

2. 创建 src/main/java/com/example/domain/Room.java 类：

   package com.example.domain;
   
   public class Room {
   
       private String name;
   
       private Room() {
       }
   
       public Room(String name) {
           this.name = name;
       }
   
       @Override
       public String toString() {
           return name;
       }
   
       // ********************************
       // Getters and setters
       // ********************************
   
       public String getName() {
           return name;
       }
   
   }

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3. 创建 src/main/java/com/example/domain/Lesson.java 类：

   package com.example.domain;
   
   import org.optaplanner.core.api.domain.entity.PlanningEntity;
   import org.optaplanner.core.api.domain.variable.PlanningVariable;
   
   @PlanningEntity
   public class Lesson {
   
       private Long id;
   
       private String subject;
       private String teacher;
       private String studentGroup;
   
       @PlanningVariable(valueRangeProviderRefs = "timeslotRange")
       private Timeslot timeslot;
   
       @PlanningVariable(valueRangeProviderRefs = "roomRange")
       private Room room;
   
       private Lesson() {
       }
   
       public Lesson(Long id, String subject, String teacher, String studentGroup) {
           this.id = id;
           this.subject = subject;
           this.teacher = teacher;
           this.studentGroup = studentGroup;
       }
   
       @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;
       }
   
   }

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   Lesson 类具有一个 @PlanningEntity 注释，因此 OptaPlanner 知道此类在解决过程中发生了变化，因为它包含一个或多个计划变量。

   timeslot 字段具有一个 @PlanningVariable 注释，因此 OptaPlanner 知道它可以更改其值。为了找到潜在的 Timeslot 实例来分配给此字段，OptaPlanner 使用 valueRangeProviderRefs 属性连接到提供 List<Timeslot&gt; 的值范围供应商。有关值范围供应商的信息，请参阅 第 18.4 节 “在规划解决方案中收集域对象”。

   room 字段还具有 @PlanningVariable 注释，原因相同。