Практикум Spring Boot — Simple CRM — Этап 6 — `CustomerService` и исключение

package com.example.crm.service;

import com.example.crm.model.Customer;
import com.example.crm.repository.CustomerRepository;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.util.List;

@Service
@Transactional
public class CustomerService {

    private final CustomerRepository customerRepository;

    public CustomerService(CustomerRepository customerRepository) {
        this.customerRepository = customerRepository;
    }

    @Transactional(readOnly = true)
    public List<Customer> findAll() {
        return customerRepository.findAllByOrderByNameAsc();
    }

    @Transactional(readOnly = true)
    public Customer findById(Long id) {
        return customerRepository.findById(id)
                .orElseThrow(() -> new CustomerNotFoundException(id));
    }

    public Customer create(Customer customer) {
        customer.setId(null);
        return customerRepository.save(customer);
    }

    public Customer update(Long id, Customer updated) {
        Customer existing = findById(id);
        existing.setName(updated.getName());
        existing.setEmail(updated.getEmail());
        existing.setPhone(updated.getPhone());
        existing.setCompany(updated.getCompany());
        existing.setNotes(updated.getNotes());
        return customerRepository.save(existing);
    }

    public void delete(Long id) {
        if (!customerRepository.existsById(id)) {
            throw new CustomerNotFoundException(id);
        }
        customerRepository.deleteById(id);
    }
}