Refatoração em Larga
Escala
Danilo Sato - @dtsato
ThoughtWorks
www.dtsato.com

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8 países
0+ esc ritórios
2
On & off shore
1600+ pessoas
$200m receita
US
Estam os contratando!
s
r ent-opportunitie
http://thou ghtworks.com/cur

Por que mudamos
código?

Por que mudamos
código?
• Adicionar funcionalidade

Por que mudamos
código?
• Adicionar funcionalidade
• Arrumar bugs

Por que mudamos
código?
• Adicionar funcionalidade
• Arrumar bugs
• Melhorar o design

Por que mudamos
código?
• Adicionar funcionalidade
• Arrumar bugs
• Melhorar o design
• Otimização

Por que mudamos
código?
• Adicionar funcionalidade
• Arrumar bugs
• Melhorar o design
• Otimização

"Refatoração é uma técnica
disciplinada para reestruturar
código, alterando sua estrutura
interna sem alterar seu
comportamento externo"

Refatoração
Código

Refatoração
Código

Refatoração
Código
Extr air Método

Refatoração
Código

Refatoração
Código

Refatoração
Código
Eliminar Duplicação

• Extrair Método
• Mover Método
• Extrair Classe
• Remover Mediador
• Auto-Encapsular Atributo
• Decompor Condicional
• ...

Testes!
Código
Teste

Testes!
Código
Teste

Testes!
Código
Teste
Eliminar Duplicação

Outros tipos...
Código
Teste

Outros tipos...
Código Código
Teste

Outros tipos...
Código Código
Teste Teste

Outros tipos...
Código Código
Teste Teste
Se paração de
Respons abilidades

Outros tipos...
Código
Teste

Outros tipos...
Teste Código

Outros tipos...
Teste Código

Outros tipos...
Teste Código
Mudança no Design

Ainda mais...

“Big Picture”

“Big Picture”

“Big Picture”

“Big Picture”

“Big Picture”

Estratégia
Mecânica

Coding Kata!

Coding Kata!

Estratégia
Mecânica

CheckoutControllerTest CheckoutController
Order Cart

m/dtsato/refact oring-experiment
ht tp://github.co
-
mant.com/2011/0 9/01/refactoring
http://paulham
experiment
CheckoutControllerTest CheckoutController
Order Cart

public class CheckoutControllerTest {
private CheckoutController checkoutController;
private Cart cart = new Cart(); // could as easily be a mock
private Order order = new Order(); // could as easily be a mock
private ModelMap model = new ModelMap();
@Before public void setup() {
checkoutController = new CheckoutController(cart, order);
}
@Test public void checkout_should_add_an_upsell() {
String result = checkoutController.goCheckout(model);
assertThat(result, equalTo("checkout"));
assertThat(model.toString(), equalTo("{cart=Cart{contents=[[iPad]]}}"));
}
@Test public void place_order_in_checkout_should_make_an_order() {
cart.addTo("dummy");
String result = checkoutController.placeOrder(model);
assertThat(result, equalTo("orderPlaced"));
assertThat(model.toString(),
equalTo("{order=Order{cart=Cart{contents=[[dummy]]}}}"));
}
}

@Controller public class CheckoutController {
private final Cart cart;
private final Order order;
@Autowired public CheckoutController(Cart cart, Order order) {
this.cart = cart;
this.order = order;
}
@RequestMapping("/go/to/checkout/") public String goCheckout(ModelMap model) {
cart.addTo(findUpsell(cart));
model.addAttribute("cart", cart);
return "checkout";
}
@RequestMapping("/place/order") public String placeOrder(ModelMap model) {
order.place(cart);
model.addAttribute("order", order);
return "orderPlaced";
}
String findUpsell(Cart cart) { return cart.size() == 0 ? "iPad" : "iPod Nano"; }
}

@Controller public class CheckoutController {
“Extrair Clas
se”
private final Cart cart; OrderControll
er em
private final Order order; placeOrder()
gerando get/s
et
@Autowired public CheckoutController(Cart cart, Order order) {
this.cart = cart;
this.order = order;
}
@RequestMapping("/go/to/checkout/") public String goCheckout(ModelMap model) {
cart.addTo(findUpsell(cart));
model.addAttribute("cart", cart);
return "checkout";
}
@RequestMapping("/place/order") public String placeOrder(ModelMap model) {
order.place(cart);
model.addAttribute("order", order);
return "orderPlaced";
}
String findUpsell(Cart cart) { return cart.size() == 0 ? "iPad" : "iPod Nano"; }
}

@Controller public class CheckoutController {
private final Cart cart;
private final Order order;
private final OrderController orderController = new OrderController(this);
@Autowired public CheckoutController(Cart cart, Order order) {
this.cart = cart;
this.order = order;
}
@RequestMapping("/go/to/checkout/") public String goCheckout(ModelMap model) {
// other stuff
cart.addTo(findUpsell(cart));
model.addAttribute("cart", cart);
return "checkout";
}
@RequestMapping("/place/order") public String placeOrder(ModelMap model) {
return orderController.placeOrder(model);
}
String findUpsell(Cart cart) { return cart.size() == 0 ? "iPad" : "iPod Nano"; }
public Order getOrder() { return order; }
public Cart getCart() { return cart; }
}

@Controller public class CheckoutController {
⌘⌥N
private final Cart cart;
“Inline” inic
private final Order order; ialização de
private final OrderController orderController = orderController
new OrderController(this);
@Autowired public CheckoutController(Cart cart, Order order) {
this.cart = cart;
this.order = order;
}
@RequestMapping("/go/to/checkout/") public String goCheckout(ModelMap model) {
// other stuff
cart.addTo(findUpsell(cart));
model.addAttribute("cart", cart);
return "checkout";
}
@RequestMapping("/place/order") public String placeOrder(ModelMap model) {
return orderController.placeOrder(model);
}
String findUpsell(Cart cart) { return cart.size() == 0 ? "iPad" : "iPod Nano"; }
public Order getOrder() { return order; }
public Cart getCart() { return cart; }
}

@Controller public class CheckoutController {
private final Cart cart;
private final Order order;
@Autowired public CheckoutController(Cart cart, Order order) {
this.cart = cart;
this.order = order;
}
@RequestMapping("/go/to/checkout/") public String goCheckout(ModelMap model) {
// other stuff
cart.addTo(findUpsell(cart));
model.addAttribute("cart", cart);
return "checkout";
}
@RequestMapping("/place/order") public String placeOrder(ModelMap model) {
return new OrderController(this).placeOrder(model);
}
String findUpsell(Cart cart) { return cart.size() == 0 ? "iPad" : "iPod Nano"; }
public Order getOrder() { return order; }
public Cart getCart() { return cart; }
}

public class OrderController {
private final CheckoutController checkoutController;
public OrderController(CheckoutController checkoutController) {
this.checkoutController = checkoutController;
}
@RequestMapping("/place/order")
public String placeOrder(ModelMap model) {
checkoutController.getOrder().place(checkoutController.getCart());
model.addAttribute("order", checkoutController.getOrder());
return "orderPlaced";
}
}

⌘⌥F
“Introduzir a
tributo” orde
cart em Order r e
Controller
public class OrderController {
private final CheckoutController checkoutController;
public OrderController(CheckoutController checkoutController) {
this.checkoutController = checkoutController;
}
@RequestMapping("/place/order")
public String placeOrder(ModelMap model) {
checkoutController.getOrder().place(checkoutController.getCart());
model.addAttribute("order", checkoutController.getOrder());
return "orderPlaced";
}
}

public class OrderController {
private final CheckoutController checkoutController;
private final Order order;
private final Cart cart;
public OrderController(CheckoutController checkoutController) {
this.checkoutController = checkoutController;
order = this.checkoutController.getOrder();
cart = this.checkoutController.getCart();
}
@RequestMapping("/place/order")
public String placeOrder(ModelMap model) {
order.place(cart);
model.addAttribute("order", order);
return "orderPlaced";
}
}

⌘⌥P / ⌥ / ⌘Y
“Introduzir p
arâmetro” ord
e cart no con er
public class OrderController { strutor de
OrderControl
private final CheckoutController checkoutController; ler e inic
ializar
private final Order order;
private final Cart cart;
public OrderController(CheckoutController checkoutController) {
this.checkoutController = checkoutController;
order = this.checkoutController.getOrder();
cart = this.checkoutController.getCart();
}
@RequestMapping("/place/order")
public String placeOrder(ModelMap model) {
order.place(cart);
model.addAttribute("order", order);
return "orderPlaced";
}
}

public class OrderController {
private final CheckoutController checkoutController;
private final Order order;
private final Cart cart;
public OrderController(CheckoutController checkoutController,
Order order, Cart cart) {
this.checkoutController = checkoutController;
this.order = order;
this.cart = cart;
}
@RequestMapping("/place/order")
public String placeOrder(ModelMap model) {
order.place(cart);
model.addAttribute("order", order);
return "orderPlaced";
}
}

⌘⌫
“Remoção Segu
ra” do atribu
public class OrderController { e parâmetro to
private final CheckoutController checkoutController;
checkoutContr
oller
private final Order order;
private final Cart cart;
public OrderController(CheckoutController checkoutController,
Order order, Cart cart) {
this.checkoutController = checkoutController;
this.order = order;
this.cart = cart;
}
@RequestMapping("/place/order")
public String placeOrder(ModelMap model) {
order.place(cart);
model.addAttribute("order", order);
return "orderPlaced";
}
}

public class OrderController {
private final Order order;
private final Cart cart;
public OrderController(Order order, Cart cart) {
this.order = order;
this.cart = cart;
}
@RequestMapping("/place/order")
public String placeOrder(ModelMap model) {
order.place(cart);
model.addAttribute("order", order);
return "orderPlaced";
}
}

@Controller public class CheckoutController {
private final Cart cart;
private final Order order;
@Autowired public CheckoutController(Cart cart, Order order) {
this.cart = cart;
this.order = order;
}
@RequestMapping("/go/to/checkout/") public String goCheckout(ModelMap model) {
// other stuff
cart.addTo(findUpsell(cart));
model.addAttribute("cart", cart);
return "checkout";
}
@RequestMapping("/place/order") public String placeOrder(ModelMap model) {
return new OrderController(order, cart).placeOrder(model);
}
String findUpsell(Cart cart) { return cart.size() == 0 ? "iPad" : "iPod Nano"; }
public Order getOrder() { return order; }
public Cart getCart() { return cart; }
}

@Controller public class CheckoutController {
⌘⌫
“Remoção Segu
private final Cart cart; ra” de getCar
e getOrder() t()
private final Order order; em
CheckoutContr
oller
@Autowired public CheckoutController(Cart cart, Order order) {
this.cart = cart;
this.order = order;
}
@RequestMapping("/go/to/checkout/") public String goCheckout(ModelMap model) {
// other stuff
cart.addTo(findUpsell(cart));
model.addAttribute("cart", cart);
return "checkout";
}
@RequestMapping("/place/order") public String placeOrder(ModelMap model) {
return new OrderController(order, cart).placeOrder(model);
}
String findUpsell(Cart cart) { return cart.size() == 0 ? "iPad" : "iPod Nano"; }
public Order getOrder() { return order; }
public Cart getCart() { return cart; }
}

@Controller public class CheckoutController {
private final Cart cart;
private final Order order;
@Autowired public CheckoutController(Cart cart, Order order) {
this.cart = cart;
this.order = order;
}
@RequestMapping("/go/to/checkout/") public String goCheckout(ModelMap model) {
// other stuff
cart.addTo(findUpsell(cart));
model.addAttribute("cart", cart);
return "checkout";
}
@RequestMapping("/place/order") public String placeOrder(ModelMap model) {
return new OrderController(order, cart).placeOrder(model);
}
String findUpsell(Cart cart) { return cart.size() == 0 ? "iPad" : "iPod Nano"; }
}

⌘⌥N
@Controller public class CheckoutController { “Inline” méto
do placeOrder
mudar argumen e
private final Cart cart; tos para usar
cart e order
private final Order order; no teste
@Autowired public CheckoutController(Cart cart, Order order) {
this.cart = cart;
this.order = order;
}
@RequestMapping("/go/to/checkout/") public String goCheckout(ModelMap model) {
// other stuff
cart.addTo(findUpsell(cart));
model.addAttribute("cart", cart);
return "checkout";
}
@RequestMapping("/place/order") public String placeOrder(ModelMap model) {
return new OrderController(order, cart).placeOrder(model);
}
String findUpsell(Cart cart) { return cart.size() == 0 ? "iPad" : "iPod Nano"; }
}

@Controller public class CheckoutController {
private final Cart cart;
private final Order order;
@Autowired public CheckoutController(Cart cart, Order order) {
this.cart = cart;
this.order = order;
}
@RequestMapping("/go/to/checkout/") public String goCheckout(ModelMap model) {
// other stuff
cart.addTo(findUpsell(cart));
model.addAttribute("cart", cart);
return "checkout";
}
String findUpsell(Cart cart) { return cart.size() == 0 ? "iPad" : "iPod Nano"; }
}

public class CheckoutControllerTest {
private CheckoutController checkoutController;
private Cart cart = new Cart(); // could as easily be a mock
private Order order = new Order(); // could as easily be a mock
private ModelMap model = new ModelMap();
@Before public void setup() {
checkoutController = new CheckoutController(cart, order);
}
@Test public void checkout_should_add_an_upsell() {
String result = checkoutController.goCheckout(model);
assertThat(result, equalTo("checkout"));
assertThat(model.toString(), equalTo("{cart=Cart{contents=[[iPad]]}}"));
}
@Test public void place_order_in_checkout_should_make_an_order() {
cart.addTo("dummy");
String result = new OrderController(order, cart).placeOrder(model);
assertThat(result, equalTo("orderPlaced"));
assertThat(model.toString(),
equalTo("{order=Order{cart=Cart{contents=[[dummy]]}}}"));
}
}

public class CheckoutControllerTest {
⌘⌥F
“ Introduzir at
private CheckoutController checkoutController; ributo”
private or be a ntro
Cart cart = new Cart(); // could as easily derComock ller no
teste,
private inicialia ando
Order order = new Order(); // could as easily be z mock no
setUp()
private ModelMap model = new ModelMap();
@Before public void setup() {
checkoutController = new CheckoutController(cart, order);
}
@Test public void checkout_should_add_an_upsell() {
String result = checkoutController.goCheckout(model);
assertThat(result, equalTo("checkout"));
assertThat(model.toString(), equalTo("{cart=Cart{contents=[[iPad]]}}"));
}
@Test public void place_order_in_checkout_should_make_an_order() {
cart.addTo("dummy");
String result = new OrderController(order, cart).placeOrder(model);
assertThat(result, equalTo("orderPlaced"));
assertThat(model.toString(),
equalTo("{order=Order{cart=Cart{contents=[[dummy]]}}}"));
}
}

public class CheckoutControllerTest {
private CheckoutController checkoutController;
private Cart cart = new Cart(); // could as easily be a mock
private Order order = new Order(); // could as easily be a mock
private ModelMap model = new ModelMap();
private OrderController orderController;
@Before public void setup() {
checkoutController = new CheckoutController(cart, order);
orderController = new OrderController(order, cart);
}
@Test public void checkout_should_add_an_upsell() {
String result = checkoutController.goCheckout(model);
assertThat(result, equalTo("checkout"));
assertThat(model.toString(), equalTo("{cart=Cart{contents=[[iPad]]}}"));
}
@Test public void place_order_in_checkout_should_make_an_order() {
cart.addTo("dummy");
String result = orderController.placeOrder(model);
assertThat(result, equalTo("orderPlaced"));
assertThat(model.toString(),
equalTo("{order=Order{cart=Cart{contents=[[dummy]]}}}"));
}
}

@Controller public class CheckoutController {
private final Cart cart;
private final Order order;
@Autowired public CheckoutController(Cart cart, Order order) {
this.cart = cart;
this.order = order;
}
@RequestMapping("/go/to/checkout/") public String goCheckout(ModelMap model) {
// other stuff
cart.addTo(findUpsell(cart));
model.addAttribute("cart", cart);
return "checkout";
}
String findUpsell(Cart cart) { return cart.size() == 0 ? "iPad" : "iPod Nano"; }
}

⌘⌫
“Remoção Segu
ra” do atribu
e parâmetro o to
@Controller public class CheckoutController { rder no
CheckoutContr
oller
private final Cart cart;
private final Order order;
@Autowired public CheckoutController(Cart cart, Order order) {
this.cart = cart;
this.order = order;
}
@RequestMapping("/go/to/checkout/") public String goCheckout(ModelMap model) {
// other stuff
cart.addTo(findUpsell(cart));
model.addAttribute("cart", cart);
return "checkout";
}
String findUpsell(Cart cart) { return cart.size() == 0 ? "iPad" : "iPod Nano"; }
}

@Controller public class CheckoutController {
private final Cart cart;
@Autowired public CheckoutController(Cart cart) {
this.cart = cart;
}
@RequestMapping("/go/to/checkout/") public String goCheckout(ModelMap model) {
// other stuff
cart.addTo(findUpsell(cart));
model.addAttribute("cart", cart);
return "checkout";
}
String findUpsell(Cart cart) { return cart.size() == 0 ? "iPad" : "iPod Nano"; }
}

Estratégia
Mecânica

Identificar Objetivo

Identificar Objetivo

Identificar Objetivo
Design “ativo”

Identificar Objetivo
Design “ativo”
• Design OO

Identificar Objetivo
Design “ativo”
• Design OO
• Direção do Projeto

Identificar Objetivo
Design “ativo”
• Design OO
• Direção do Projeto
• Decisões Arquiteturais

Identificar Objetivo
Design “passivo”

Identificar Objetivo
Design “passivo”
• Maus Cheiros

Identificar Objetivo
Design “passivo”
• Maus Cheiros
• Métricas

Identificar Objetivo
Design “passivo”
• Maus Cheiros
• Métricas
• Visualizações

Traçar Estratégia

Traçar Estratégia
? ?
?

Traçar Estratégia

Traçar Estratégia
• Isole o Impacto das Mudanças

Traçar Estratégia
• Isole o Impacto das Mudanças
• Baby Steps

Traçar Estratégia
• Isole o Impacto das Mudanças
• Baby Steps
• Mantenha os testes passando

Traçar Estratégia
• Isole o Impacto das Mudanças
• Baby Steps
• Mantenha os testes passando
• Ir para trás antes de ir para frente

CalendarSearchController
CalendarSearchController
Test
Event Event

r
dtsato/kata-ref actoring-calenda
http ://github.com/
CalendarSearchController
CalendarSearchController
Test
Event Event

def index(params)
scope = Event
case params[:timeframe]
when 'tomorrow'
scope = scope.between_day(DateTime.now + 1)
when 'this_week'
scope = scope.between_dates(DateTime.now, ( DateTime.now + 6 ).end_of_day)
when 'custom'
if params[:start_date].blank?
params[:start_date] = DateTime.now.beginning_of_week.strftime('%m/%d/%Y')
end
if params[:end_date].blank?
params[:end_date] = (DateTime.now.end_of_week - 2).strftime('%m/%d/%Y')
end
scope = scope.between_dates(DateTime.strptime(params[:start_date], '%m/%d/%Y'),
DateTime.strptime(params[:end_date], '%m/%d/%Y').end_of_day)
when 'hour'
scope = scope.between_hour_on_day(DateTime.strptime(params[:hour], '%m/%d/%Y %H:
%M'))
when 'today'
scope = scope.between_day(DateTime.now)
end
@events = scope.all
end

def index(params)
scope = Event switch/case
case params[:timeframe]
when 'tomorrow'
scope = scope.between_day(DateTime.now + 1)
when 'this_week'
scope = scope.between_dates(DateTime.now, ( DateTime.now + 6 ).end_of_day)
when 'custom'
if params[:start_date].blank?
params[:start_date] = DateTime.now.beginning_of_week.strftime('%m/%d/%Y')
end
if params[:end_date].blank?
params[:end_date] = (DateTime.now.end_of_week - 2).strftime('%m/%d/%Y')
end
scope = scope.between_dates(DateTime.strptime(params[:start_date], '%m/%d/%Y'),
DateTime.strptime(params[:end_date], '%m/%d/%Y').end_of_day)
when 'hour'
scope = scope.between_hour_on_day(DateTime.strptime(params[:hour], '%m/%d/%Y %H:
%M'))
when 'today'
scope = scope.between_day(DateTime.now)
end
@events = scope.all
end

def index(params)
scope = Event
case params[:timeframe]
when 'tomorrow'
scope = scope.between_day(DateTime.now + 1)
when 'this_week'
string parsing
scope = scope.between_dates(DateTime.now, ( DateTime.now + 6 ).end_of_day)
when 'custom'
if params[:start_date].blank?
params[:start_date] = DateTime.now.beginning_of_week.strftime('%m/%d/%Y')
end
if params[:end_date].blank?
params[:end_date] = (DateTime.now.end_of_week - 2).strftime('%m/%d/%Y')
end
scope = scope.between_dates(DateTime.strptime(params[:start_date], '%m/%d/%Y'),
DateTime.strptime(params[:end_date], '%m/%d/%Y').end_of_day)
when 'hour'
scope = scope.between_hour_on_day(DateTime.strptime(params[:hour], '%m/%d/%Y %H:
%M'))
when 'today'
scope = scope.between_day(DateTime.now)
end
@events = scope.all
end

def index(params)
scope = Event
case params[:timeframe]
when 'tomorrow'
scope = scope.between_day(DateTime.now + 1)
when 'this_week'
scope = scope.between_dates(DateTime.now, ( DateTime.now + 6 ).end_of_day)
when 'custom'
if params[:start_date].blank?
params[:start_date] = DateTime.now.beginning_of_week.strftime('%m/%d/%Y')
end
if params[:end_date].blank?
params[:end_date] = (DateTime.now.end_of_week - 2).strftime('%m/%d/%Y')
end
scope = scope.between_dates(DateTime.strptime(params[:start_date], '%m/%d/%Y'),
DateTime.strptime(params[:end_date], '%m/%d/%Y').end_of_day)
when 'hour'
scope = scope.between_hour_on_day(DateTime.strptime(params[:hour], '%m/%d/%Y %H:
%M'))
when 'today'
scope = scope.between_day(DateTime.now)
end
vários named scopes
@events = scope.all
end

class Event < ActiveRecord::Base
named_scope :between_dates, lambda { |start_date, end_date|
{:conditions => ["at >= ? AND at <= ?", start_date, end_date ] }
}
named_scope :between_hour_on_day, lambda { |start_hour|
end_date = start_hour + 1.hour-1.second
{ :conditions => {:at => start_hour..end_date} }
}
named_scope :between_day, lambda { |date|
start_date = date.at_beginning_of_day
end_date = start_date.end_of_day
{ :conditions => {:at => start_date..end_date} }
}
end

jeitos diferentes de
fazer a mesma
class Event < ActiveRecord::Base
coisa
named_scope :between_dates, lambda { |start_date, end_date|
{:conditions => ["at >= ? AND at <= ?", start_date, end_date ] }
}
named_scope :between_hour_on_day, lambda { |start_hour|
end_date = start_hour + 1.hour-1.second
{ :conditions => {:at => start_hour..end_date} }
}
named_scope :between_day, lambda { |date|
start_date = date.at_beginning_of_day
end_date = start_date.end_of_day
{ :conditions => {:at => start_date..end_date} }
}
end

class Event < ActiveRecord::Base
named_scope :between_dates, lambda { |start_date, end_date|
{:conditions => ["at >= ? AND at <= ?", start_date, end_date ] }
}
named_scope :between_hour_on_day, lambda { |start_hour|
end_date = start_hour + 1.hour-1.second
{ :conditions => {:at => start_hour..end_date} }
}
mais lógica
named_scope :between_day, lambda { |date|
start_date = date.at_beginning_of_day
end_date = start_date.end_of_day
{ :conditions => {:at => start_date..end_date} }
}
end

Objetivos
Ativo:
• Isolar testes unitários do banco de dados
Passivo:
• Tratar dos maus cheiros

O Plano
1. Centralizar a lógica de manipulação de datas
2. Unificar named scopes
3. Extrair lógica do Controller
4. Quebrar timeframe em vários pedaços

def index(params)
case params[:timeframe]
when 'tomorrow'
date = DateTime.now + 1
start_date = date.at_beginning_of_day
end_date = start_date.end_of_day
when 'this_week'
start_date = DateTime.now
end_date = (DateTime.now + 6 ).end_of_day
when 'custom'
start_date = params[:start_date].blank? ? DateTime.now.beginning_of_week :
DateTime.strptime(params[:start_date], '%m/%d/%Y')
end_date = params[:end_date].blank? ? (DateTime.now.end_of_week - 2) :
DateTime.strptime(params[:end_date], '%m/%d/%Y').end_of_day
when 'hour'
start_date = DateTime.strptime(params[:hour], '%m/%d/%Y %H:%M')
end_date = start_date + 1.hour-1.second
when 'today'
date = DateTime.now
start_date = date.at_beginning_of_day
end_date = start_date.end_of_day
end
@events = Event.between_dates(start_date, end_date)
end

class Event < ActiveRecord::Base
named_scope :between_dates, lambda { |start_date, end_date|
{:conditions => {:at => start_date..end_date}}
}
end

class Event < ActiveRecord::Base
named_scope :between_dates, lambda { |start_date, end_date|
{:conditions => {:at => start_date..end_date}}
}
end
lib/calendar_search_controller.rb | 27 +++++++++++++--------------
lib/event.rb | 13 +------------
spec/event_spec.rb | 37 -------------------------------------
3 files changed, 14 insertions(+), 63 deletions(-)

Antes
.
............
ds
0 .49367 secon
Finished in res
13 examp les, 0 failu
class Event < ActiveRecord::Base
named_scope :between_dates, lambda { |start_date, end_date|
{:conditions => {:at => start_date..end_date}}
}
end
lib/calendar_search_controller.rb | 27 +++++++++++++--------------
lib/event.rb | 13 +------------
spec/event_spec.rb | 37 -------------------------------------
3 files changed, 14 insertions(+), 63 deletions(-)

Antes Depois
.......
.
............
ds Finished in
0 .49367 secon 0.25355 seco
Finished in res 7 examples, nds
13 examp les, 0 failu 0 failures
class Event < ActiveRecord::Base
named_scope :between_dates, lambda { |start_date, end_date|
{:conditions => {:at => start_date..end_date}}
}
end
lib/calendar_search_controller.rb | 27 +++++++++++++--------------
lib/event.rb | 13 +------------
spec/event_spec.rb | 37 -------------------------------------
3 files changed, 14 insertions(+), 63 deletions(-)

O Plano
1. Centralizar a lógica de manipulação de datas
2. Unificar named scopes
3. Extrair lógica do Controller
4. Quebrar timeframe em vários pedaços

class CalendarSearchController
attr_reader :events
def index(params)
timeframe = TimeFrame.for(params[:timeframe], params[:start_date],
params[:end_date], params[:hour])
@events = Event.between_dates(timeframe.start_date, timeframe.end_date)
end
end
mudança nos testes:
it "should create time frame from params and retrieve events" do
timeframe = TimeFrame.new(DateTime.now, DateTime.now)
TimeFrame.should_receive(:for).with('today', 'start', 'end',
'hour').and_return(timeframe)
events = [Event.new, Event.new]
Event.should_receive(:between_dates).with(timeframe.start_date,
timeframe.end_date).and_return(events)
@controller.index(:timeframe => 'today', :start_date => 'start', :end_date =>
'end', :hour => 'hour')
@controller.events.should == events
end

describe "Acceptance tests" do
around(:each) do |example|
Event.transaction { example.run; raise ActiveRecord::Rollback }
end
before do
@controller = CalendarSearchController.new
@today = DateTime.strptime('06/01/2011', '%m/%d/%Y')
DateTime.stub!(:now).and_return(@today)
end
it "should return today's events" do
today_events = [Event.create(:at => @today), Event.create(:at => @today)]
tomorrow = @today + 1
tomorrow_events = [Event.create(:at => tomorrow), Event.create(:at => tomorrow)]
@controller.index(:timeframe => 'today')
@controller.events.should == today_events
end
it "should return tomorrow's events" ...
it "should return this week's events" ...
it "should return events for specified date range" ...
it "should default date range to this business week" ...
it "returns events for a specified hour" ...
end

describe "Acceptance tests" do
around(:each) do |example| Depois
......
Event.transaction { example.run; raise ActiveRecord::Rollback }
end
Finished in
0.24538 seco
before do 6 examples, nds
0 failures
@controller = CalendarSearchController.new
@today = DateTime.strptime('06/01/2011', '%m/%d/%Y')
DateTime.stub!(:now).and_return(@today)
end
it "should return today's events" do
today_events = [Event.create(:at => @today), Event.create(:at => @today)]
tomorrow = @today + 1
tomorrow_events = [Event.create(:at => tomorrow), Event.create(:at => tomorrow)]
@controller.index(:timeframe => 'today')
@controller.events.should == today_events
end
it "should return tomorrow's events" ...
it "should return this week's events" ...
it "should return events for specified date range" ...
it "should default date range to this business week" ...
it "returns events for a specified hour" ...
end

class TimeFrame < Struct.new(:start_date, :end_date)
def self.for(type, start_date, end_date, hour)
case type
when 'tomorrow'
date = DateTime.now + 1
TimeFrame.new(date.at_beginning_of_day, date.end_of_day)
when 'this_week'
TimeFrame.new(DateTime.now, (DateTime.now + 6 ).end_of_day)
when 'custom'
start_date = start_date.blank? ? DateTime.now.beginning_of_week :
DateTime.strptime(start_date, '%m/%d/%Y')
end_date = end_date.blank? ? (DateTime.now.end_of_week - 2) :
DateTime.strptime(end_date, '%m/%d/%Y').end_of_day
TimeFrame.new(start_date, end_date)
when 'hour'
start_date = DateTime.strptime(hour, '%m/%d/%Y %H:%M')
end_date = start_date + 1.hour-1.second
TimeFrame.new(start_date, end_date)
when 'today'
date = DateTime.now
TimeFrame.new(date.at_beginning_of_day, date.end_of_day)
end
end
end

describe TimeFrame do
before do
@today = DateTime.strptime('06/01/2011', '%m/%d/%Y')
DateTime.stub!(:now).and_return(@today)
end
describe "today's event" do
it "should use beginning and end of day" do
timeframe = TimeFrame.for('today', nil, nil, nil)
timeframe.start_date.should == @today.at_beginning_of_day
timeframe.end_date.should == @today.end_of_day
end
end
...
end

describe TimeFrame do
before do
@today = DateTime.strptime('06/01/2011', '%m/%d/%Y')
DateTime.stub!(:now).and_return(@today)
end
describe "today's event" do
it "should use beginning and end of day" do
timeframe = TimeFrame.for('today', nil, nil, nil)
timeframe.start_date.should == @today.at_beginning_of_day
timeframe.end_date.should == @today.end_of_day
end
Rakefile | 4 ++
end
lib/calendar_search_controller.rb | 24 +---------
...
lib/time_frame.rb | 24 ++++++++++
end
spec/acceptance_tests.rb | 75 +++++++++++++++++++++++++++++++
spec/calendar_search_controller_spec.rb | 75 ++++---------------------------
spec/time_frame_spec.rb | 63 ++++++++++++++++++++++++++
6 files changed, 178 insertions(+), 87 deletions(-)

Antes
.......
ds
describe d in 0 .25355 secon
Finishe TimeFrame do es
before les, 0 failur
7 examp do
@today = DateTime.strptime('06/01/2011', '%m/%d/%Y')
DateTime.stub!(:now).and_return(@today)
end
describe "today's event" do
it "should use beginning and end of day" do
timeframe = TimeFrame.for('today', nil, nil, nil)
timeframe.start_date.should == @today.at_beginning_of_day
timeframe.end_date.should == @today.end_of_day
end
Rakefile | 4 ++
end
lib/calendar_search_controller.rb | 24 +---------
...
lib/time_frame.rb | 24 ++++++++++
end
spec/acceptance_tests.rb | 75 +++++++++++++++++++++++++++++++
spec/calendar_search_controller_spec.rb | 75 ++++---------------------------
spec/time_frame_spec.rb | 63 ++++++++++++++++++++++++++
6 files changed, 178 insertions(+), 87 deletions(-)

Antes Depois
........
.......
ds Finished in
describe d in 0 .25355 secon
she TimeFrame do
0.17938 seco
nds
Fini 8 examples,
before les, 0 failures
7 ex amp do
0 failures
@today = DateTime.strptime('06/01/2011', '%m/%d/%Y')
DateTime.stub!(:now).and_return(@today)
end
describe "today's event" do
it "should use beginning and end of day" do
timeframe = TimeFrame.for('today', nil, nil, nil)
timeframe.start_date.should == @today.at_beginning_of_day
timeframe.end_date.should == @today.end_of_day
end
Rakefile | 4 ++
end
lib/calendar_search_controller.rb | 24 +---------
...
lib/time_frame.rb | 24 ++++++++++
end
spec/acceptance_tests.rb | 75 +++++++++++++++++++++++++++++++
spec/calendar_search_controller_spec.rb | 75 ++++---------------------------
spec/time_frame_spec.rb | 63 ++++++++++++++++++++++++++
6 files changed, 178 insertions(+), 87 deletions(-)

O Plano
1. Centralizar a lógica de manipulação de datas
2. Unificar named scopes
3. Extrair lógica do Controller
4. Quebrar timeframe em vários pedaços

class TimeFrame
attr_reader :start_date, :end_date
class Today < TimeFrame
def initialize
date = DateTime.now
@start_date, @end_date = date.at_beginning_of_day, date.end_of_day
end
end
...
end
describe TimeFrame::Today do
it "should use beginning and end of day" do
timeframe = TimeFrame::Today.new
timeframe.start_date.should == @today.at_beginning_of_day
timeframe.end_date.should == @today.end_of_day
end
...
end

class TimeFrame
...
def self.for(type, start_date, end_date, hour)
case type
when 'tomorrow' then Tomorrow.new
when 'this_week' then ThisWeek.new
when 'custom' then Custom.new(start_date, end_date)
when 'hour' then Hour.new(hour)
when 'today' then Today.new
end
end
end
describe TimeFrame::Today do
...
describe "parsing" do
it "should parse today's timeframe" do
TimeFrame.for('today', nil, nil, nil).should
be_an_instance_of(TimeFrame::Today)
end
...
end
end

class TimeFrame
... Antes
.def .self.for(type, start_date, end_date, hour)
... ...
case type
ds
0 .17938 secon
when 'tomorrow' then Tomorrow.new
Finished in
when les, 0 failures ThisWeek.new
8 examp 'this_week' then
when 'custom' then Custom.new(start_date, end_date)
when 'hour' then Hour.new(hour)
when 'today' then Today.new
end
end
end
describe TimeFrame::Today do
...
describe "parsing" do
it "should parse today's timeframe" do
TimeFrame.for('today', nil, nil, nil).should
be_an_instance_of(TimeFrame::Today)
end
...
end
end

class TimeFrame
... Antes Depois
............
def .self.for(type, start_date, end_date, hour) .
.... ...
case type
ds Finished in
when d in 0 .17938 secon
she 'tomorrow' then Tomorrow.new
0.19023 seco
nds
Fini 13 examples,
when les, 0 failures ThisWeek.new
8 examp 'this_week' then
0 failures
when 'custom' then Custom.new(start_date, end_date)
when 'hour' then Hour.new(hour)
when 'today' then Today.new
end
end
end
describe TimeFrame::Today do
...
describe "parsing" do
it "should parse today's timeframe" do
TimeFrame.for('today', nil, nil, nil).should
be_an_instance_of(TimeFrame::Today)
end
...
end
end

class TimeFrame
... Antes Depois
............
def .self.for(type, start_date, end_date, hour) .
.... ...
case type
ds Finished in
when d in 0 .17938 secon
she 'tomorrow' then Tomorrow.new
0.19023 seco
nds
Fini 13 examples,
when les, 0 failures ThisWeek.new
8 examp 'this_week' then
0 failures
when 'custom' then Custom.new(start_date, end_date)
when 'hour' then Hour.new(hour)
when 'today' then Today.new
end
end
end
describe TimeFrame::Today do
...
describe "parsing" do
lib/time_frame.rb | 59 +++++++++++++++++++++++++++++++++-------------
it "should parse today's timeframe" do
spec/time_frame_spec.rb | 44 ++++++++++++++++++++++++++--------
TimeFrame.for('today', nil, nil, nil).should
2 files changed, 75 insertions(+), 28 deletions(-)
be_an_instance_of(TimeFrame::Today)
end
...
end
end

Estratégia
Mecânica

“Big Picture”
• Mudanças Arquiteturais
• Unificação de abordagens diferentes
• Substituição de componentes/frameworks

“Big Picture”

“Big Picture”
Escopo Risco Esforço Comunicação

Mikado Method
Criar pacote para Stranger
Eons Ltda.

Mikado Method
Criar projeto para
Stranger Eons Ltda.
Criar pacote para Stranger
Eons Ltda.

Mikado Method
Criar projeto para Criar teste de aceitação
Stranger Eons Ltda. para nova aplicação
Criar pacote para Stranger
Eons Ltda.

Mikado Method
Código de UI em projeto
separado
Criar projeto para Criar teste de aceitação
Stranger Eons Ltda. para nova aplicação
Criar pacote para Stranger
Eons Ltda.

Mikado Method
Mover código UI para
novo projeto
Criar projeto UI
Código de UI em projeto
separado
Criar projeto para Criar teste de aceitação
Stranger Eons Ltda. para nova aplicação
Criar pacote para Stranger
Eons Ltda.

Mikado Method
Quebrar dependência
circular entre Aplicação e UI
Mover código UI para
novo projeto
Criar projeto UI
Código de UI em projeto
separado
Criar projeto para Criar teste de aceitação
Stranger Eons Ltda. para nova aplicação
Criar pacote para Stranger
Eons Ltda.

Mikado Method
Extrair ApplicationInterface
Quebrar dependência
circular entre Aplicação e UI
Mover código UI para
novo projeto
Criar projeto UI
Código de UI em projeto
separado
Criar projeto para Criar teste de aceitação
Stranger Eons Ltda. para nova aplicação
Criar pacote para Stranger
Eons Ltda.

Mikado Method
Extrair ApplicationInterface
Injetar instância de
ApplicationInterface
Quebrar dependência
circular entre Aplicação e UI
Mover código UI para
novo projeto
Criar projeto UI
Código de UI em projeto
separado
Criar projeto para Criar teste de aceitação
Stranger Eons Ltda. para nova aplicação
Criar pacote para Stranger
Eons Ltda.

Mikado Method
✔
Extrair ApplicationInterface
Injetar instância de
✔
ApplicationInterface
Quebrar dependência
✔
circular entre Aplicação e UI
Mover código UI para
novo projeto
Criar projeto UI
Código de UI em projeto
separado
Criar projeto para Criar teste de aceitação
Stranger Eons Ltda. para nova aplicação
Criar pacote para Stranger
Eons Ltda.

Mikado Method
✔
Extrair ApplicationInterface
Injetar instância de
✔
ApplicationInterface
Quebrar dependência
✔
circular entre Aplicação e UI
Mover código UI para ✔
novo projeto
✔
✔
Criar projeto UI
Código de UI em projeto
separado
Criar projeto para Criar teste de aceitação
Stranger Eons Ltda. para nova aplicação
Criar pacote para Stranger
Eons Ltda.

Mikado Method
✔
Extrair ApplicationInterface
Injetar instância de
✔
ApplicationInterface
Quebrar dependência
✔
circular entre Aplicação e UI
Mover código UI para ✔
novo projeto
✔
✔
Criar projeto UI
Código de UI em projeto
separado
Criar projeto para ✔ Criar teste de aceitação ✔
Stranger Eons Ltda. para nova aplicação
✔
Criar pacote para Stranger
Eons Ltda.

Uma história
APP

Uma história
APP
SVC

Uma história
APP
SVC

Uma história
APP
SVC

A verdade
APP
Model
View
Controller

A verdade
APP
Model
View
Controller
Helper

A verdade
APP
Model
View
SVC
Controller
Helper

A verdade
APP
Model
View
SVC
Controller
vai quebrar
tudo !!!
Helper

Arquitetura de
transição
APP
Model
View
Controller
SVC
Helper

Arquitetura de
transição
APP
Model
View
Controller
SVC
Helper

Arquitetura de
transição
APP
Model
View
Controller
SVC
Helper

Arquitetura de
transição
APP
Model
View
Controller
SVC
Helper

Arquitetura de
transição
APP
Model
View
Controller
SVC
Helper

Arquitetura de
transição
APP
Model
View
Controller
SVC
Helper

Arquitetura de
Transição
• Go:
• “Branch by Abstraction”
• Migrar de iBatis para Hibernate
• Migrar de Velocity/JsTemplate para JRuby
on Rails

Arquitetura de
Transição
• Go:
• “Branch by Abstraction”
• Migrar de iBatis para Hibernate
• Migrar de Velocity/JsTemplate para JRuby
on Rails
-
0 11/05/make-large
http://continuo usdelivery.com/2
-
l y-with-branch-by
scale-cha nges-incremental
abstraction/

Referências
Livros:
"Refactoring: Improving the Design of Existing Code" - Martin Fowler, Kent Beck, John
Brant, William Opdyke, Don Roberts
"Refactoring to Patterns" - Joshua Kerievsky
"Working Effectively with Legacy Code" - Michael Feathers
"Beheading the Software Beast: Relentless Restructurings with The Mikado Method" -
Daniel Brolund, Ola Ellnestam
Créditos (fotos):
http://www.flickr.com/photos/dhammza/2227347832/
http://www.flickr.com/photos/pragdave/173640462/
Links:
http://paulhammant.com/2011/09/01/refactoring-experiment
http://continuousdelivery.com/2011/05/make-large-scale-changes-incrementally-with-
branch-by-abstraction/
Código:
https://github.com/dtsato/refactoring_experiment
https://github.com/dtsato/kata-refactoring-calendar

S etembro (18h):
Segun da-Feira, 12 de
/ join-revolution
http://thought works.com/events

Obrigado!
Danilo Sato - @dtsato
ThoughtWorks
www.dtsato.com