CourseRepository.java

package com.example.demo.repository;

import static com.example.demo.generated.jooq.Tables.COURSES;

import com.example.demo.generated.jooq.tables.records.CoursesRecord;
import com.example.demo.model.Course;
import com.example.demo.model.Course.Visibility;
import java.util.List;
import java.util.Optional;
import org.jooq.DSLContext;
import org.springframework.stereotype.Repository;

@Repository
public class CoursesRepository {
  private final DSLContext db;

  public CoursesRepository(DSLContext db) {
    this.db = db;
  }

  public Optional<Course> findOne(long id) {
    return db
        .selectFrom(COURSES)
        .where(COURSES.ID.eq(id))
        .fetchOptional(this::mapper);
  }

  public List<Course> findAll() {
    return db
        .selectFrom(COURSES)
        .fetch(this::mapper);
  }

  public Optional<Course> create(Course course)  {
    var record = mapper(course);
    record.attach(db.configuration());
    record.changed(COURSES.ID, false);

    if (record.store() > 0) {
      return Optional.of(mapper(record));
    }

    return Optional.empty();
  }

  private CoursesRecord mapper(Course course) {
    var record = new CoursesRecord();
    record.setId(course.getId());
    record.setName(course.getName());
    record.setStartAt(course.getStartAt());
    record.setVisibility(course.getVisibility().toString());
    record.setSeats(course.getSeats());
    record.setEnrollmentActive(course.isEnrollmentActive());

    return record;
  }

  private Course mapper(CoursesRecord record) {
    if (record == null) {
      return null;
    }

    return new Course(
        record.getId(),
        record.getName(),
        record.getStartAt(),
        Visibility.valueOf(record.getVisibility()),
        record.getSeats(),
        record.getEnrollmentActive()
    );
  }
}

CourseRepositoryTest.java

package com.example.demo.repository;

import static org.junit.jupiter.api.Assertions.assertEquals;

import com.example.demo.model.Course;
import org.jooq.DSLContext;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.autoconfigure.jooq.JooqTest;

@JooqTest
class CoursesRepositoryTest {

  @Autowired
  DSLContext db;

  CoursesRepository repository;

  @BeforeEach
  void setUp() {
    repository = new CoursesRepository(db);
  }

  @Test
  void itCanLookUpACourse() {
    var course = new Course();
    course.setName("Test Course");

    var expected = repository.create(course).orElseThrow();
    var result = repository.findOne(expected.getId()).orElseThrow();

    assertEquals(expected.getName(), result.getName());
  }
}