ProductsController.java

@RestController
@RequestMapping("/api/v1/products")
public class ProductsController {

	@Autowired
	ProductsRepository productsRepository;
	@Autowired
	AuditService auditService;

	@PostMapping("")
	ResponseEntity<Product> create(@RequestBody Product product, Principal principal) {

		product.setId(UUID.randomUUID());
		product.setCreatedAt((LocalDateTime.now(ZoneOffset.UTC).withNano(0)));
		product.setUpdatedAt((LocalDateTime.now(ZoneOffset.UTC).withNano(0)));
		productsRepository.save(product);
		auditService.commit(principal.getName(), product);
		return new ResponseEntity<>(product, HttpStatus.CREATED);
	}

	@GetMapping("")
	List<Product> list() {

		return (List<Product>) productsRepository.findAll();
	}

	@PutMapping("/{id}")
	ResponseEntity<Product> update(@PathVariable UUID id, @RequestBody Product product, Principal principal) {

		return productsRepository.findById(id).map(p -> {
			p.setName(product.getName());
			p.setDescription(product.getDescription());
			p.setUpdatedAt((LocalDateTime.now(ZoneOffset.UTC).withNano(0)));
			productsRepository.save(p);
			auditService.commit(principal.getName(), p);
			return new ResponseEntity<>(p, HttpStatus.OK);
		}).orElse(new ResponseEntity<>(HttpStatus.NOT_FOUND));
	}

	@GetMapping("{id}/versions")
	ResponseEntity<List<VersionDTO<Product>>> getVersions(@PathVariable UUID id) {

		return productsRepository.findById(id).map(p -> {
			List<VersionDTO<Product>> list = auditService.getVersions(p, id);
			return new ResponseEntity<>(list, HttpStatus.OK);
		}).orElse(new ResponseEntity<>(HttpStatus.NOT_FOUND));
	}

	@GetMapping("{id}/versions/diff")
	ResponseEntity<List<VersionsDiffDTO>> getDiff(@PathVariable UUID id, @RequestParam int left, @RequestParam int right) {

		return productsRepository.findById(id).map(p -> {
			List<VersionsDiffDTO> diff = auditService.compare(Product.class, id, left, right);
			return new ResponseEntity<>(diff, HttpStatus.OK);
		}).orElse(new ResponseEntity<>(HttpStatus.NOT_FOUND));
	}

	@PutMapping("/{id}/versions")
	ResponseEntity<Product> changeVersion(@PathVariable UUID id, @RequestHeader Integer version) {

		return productsRepository.findById(id).map(cs -> {
			Product c = auditService.getVersion(Product.class, id, version);
			productsRepository.save(c);
			return new ResponseEntity<>(c, HttpStatus.OK);
		}).orElse(new ResponseEntity<>(HttpStatus.NOT_FOUND));
	}
}