ShortCourseNameJson.java

  @JsonSerialize(using = CourseSerializer.class)
  @JsonDeserialize(using = CourseDeserializer.class)
  public static class Course {

    private final Department department;
    private final long courseNumber;

    public Course(Department department, long courseNumber) {
      assert department != null;
      this.department = department;
      this.courseNumber = courseNumber;
    }

    public long getCourseNumber() {
      return courseNumber;
    }

    public Department getDepartment() {
      return department;
    }
  }

  public static class CourseSerializer extends JsonSerializer<Course> {
    @Override
    public void serialize(Course course, JsonGenerator jsonGenerator, SerializerProvider serializerProvider)
        throws IOException, JsonProcessingException {
      jsonGenerator.writeString(course.getDepartment().getShortName() + "-" + course.getCourseNumber());
    }
  }

  public static class CourseDeserializer extends JsonDeserializer<Course> {
    @Override
    public Course deserialize(JsonParser jsonParser, DeserializationContext deserializationContext)
        throws IOException, JsonProcessingException {
      final String courseParts[] = jsonParser.getText().split("-", 2);
      assert courseParts.length == 2;

      final Department department = Department.fromShortName(courseParts[0]);
      assert department != null;

      final long courseNumber = Long.parseLong(courseParts[1]);

      return new Course(department, courseNumber);
    }
  }