#transactions code explainers

java

@Service
public class OrderCheckoutService {
 
    private final OrderRepository orderRepository;

How @Transactional guards a Spring checkout

dependency-injection transactions atomicity

Intermediate 6 steps

java

package com.example.maintenance;
 
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

How a scheduled cleanup job runs in Spring

scheduling cron transactions

Intermediate 6 steps

java

@Service
public class ProductCatalogService {
 
    private final ProductRepository productRepository;

How Spring cache annotations keep data fresh

caching cache-invalidation dependency-injection

Intermediate 7 steps

java

@Service
public class OrderService {
 
    private final OrderRepository orderRepository;

Decoupling side effects with Spring events

event-driven transactions decoupling

Intermediate 8 steps

java

@Entity
@Table(name = "accounts")
public class Account {

Optimistic locking with @Version in Spring

optimistic-locking jpa concurrency

Advanced 7 steps

ruby

class PaymentsController < ApplicationController
  before_action :require_idempotency_key
 
  def create

Idempotent payment creation in Rails

idempotency transactions race-conditions

Advanced 10 steps

java

@Repository
public interface OrderRepository extends JpaRepository<Order, Long> {
 
    @QueryHints(@QueryHint(name = HINT_FETCH_SIZE, value = "1000"))

Streaming large result sets in Spring Data JPA

streaming jpa memory-management

Advanced 6 steps

ruby

class CheckoutService
  Result = Struct.new(:success?, :order, :error, keyword_init: true)
 
  def self.call(...)

How a Rails checkout service object works

service object transactions result object

Intermediate 9 steps

ruby

class RegistrationForm
  include ActiveModel::Model
  include ActiveModel::Attributes

How a Rails form object spans two models

form object validations transactions

Intermediate 7 steps

ruby

module FileResource
  # Opens a file, yields it to the caller, and guarantees the
  # handle is closed even if the block raises an exception.
  def self.open(path, mode = "r")

Guaranteeing cleanup with begin/ensure in Ruby

resource-management exception-safety blocks

Intermediate 8 steps