in google-cloud-spanner-hibernate-samples/spring-data-jpa-full-sample/src/main/java/com/google/cloud/spanner/sample/service/ConcertService.java [82:105]
public List<Concert> generateRandomConcerts(List<Singer> singers, List<Venue> venues, int count) {
Random random = new Random();
List<Concert> concerts = new ArrayList<>(count);
for (int i = 0; i < count; i++) {
Concert concert = new Concert();
concert.setName(randomDataService.getRandomConcertName());
concert.setSinger(singers.get(random.nextInt(singers.size())));
concert.setVenue(venues.get(random.nextInt(venues.size())));
concert.setStartTime(
OffsetDateTime.of(
random.nextInt(30) + 1995,
random.nextInt(12) + 1,
random.nextInt(28) + 1,
random.nextInt(24),
random.nextBoolean() ? 0 : 30,
0,
0,
ZoneOffset.ofHours(random.nextInt(24) - 12)));
concert.setEndTime(concert.getStartTime().plus(Duration.ofHours(random.nextInt(6) + 1)));
concerts.add(concert);
}
return repository.saveAll(concerts);
}