The absolute beginner’s guide to DDD with Symfony

DDD is one of the most effective ways to address business problems, but it can be overwhelming to get started with. Even armed with the theory, beginning the journey is mysterious and finding answers to specific implementation details can be tough and scary.

In this talk we'll demystify the terminology and work out the most important aspects of DDD you'll need to get you going.

Then, by exploring and implementing a sample business domain, we'll discover such things as:
- How DDD entities differ from Doctrine entities
- What an aggregate root actually is
- How to organise your code
- How to define a bounded context
- How a domain service differs from an application service

Finally, we'll wire it all together with Symfony 5. So if you've been wanting to get started with DDD for a while but never knew how or where to start then this talk is for you.

Transcript

1. The absolute beginner’s
   guide
   to Domain-Driven Design with Symfony
   

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2. What’s the point?
   

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3. What’s the point?
   

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4. What’s the point?
   Tackling complexity in the
   heart of software
   

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5. What’s the point?
   

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6. What’s the point?
   

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7. What’s the point?
   

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9. Domain-Driven
   Design
   Beginner’s Guide
   

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12. What is Domain-Driven Design?
    

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13. DDD is an approach to
    understanding the business in
    order to represent it in software,
    and also an architectural pattern
    for simplifying business problems
    

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14. Definitions & revision
    

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15. Domain
    

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16. Domain Experts
    

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17. Ubiquitous Language
    

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18. The software must use the
    same words as the business
    

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19. Property
    

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20. Instruction
    

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21. Instruction
    Property
    

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22. Bounded Contexts
    

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26. A Bounded Context is a logical
    boundary around some
    behaviour within the business
    

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27. Entities
    

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28. A DDD entity is a class which
    has some sort of identity,
    making it unique from other
    identical objects
    

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29. Aggregates
    

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30. An aggregate is a collection of
    objects that represent one
    concept in the domain
    

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31. Aggregate Roots
    

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32. The aggregate root is the
    entry-point into the aggregate
    

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33. Invariants
    

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34. Invariants are business rules
    which are enforced in the
    domain code.
    They are separate to
    application-level rules.
    

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35. Domain Services and Application Services
    

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36. Domain services contain domain
    logic which doesn’t naturally fit
    within an aggregate, entity, or
    value object
    

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37. Application services orchestrate
    the execution of domain logic
    according to outside-world
    input, but don’t contain any
    domain logic themselves
    

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38. Architecture
    

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39. 4 layers of a DDD architecture
    Each bounded context contains:
    ● Domain / Model
    ● Infrastructure
    ● Application
    ● UI
    

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40. 4 layers of a DDD architecture
    Each bounded context contains:
    ● Domain / Model
    ● Infrastructure
    ● Application
    ● UI
    Contains all business logic / invariants, entities,
    domain services, and interfaces to allow
    communication with the outside world.
    Must not depend on anything outside of the
    domain layer.
    

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41. 4 layers of a DDD architecture
    Each bounded context contains:
    ● Domain / Model
    ● Infrastructure
    ● Application
    ● UI
    Contains concretions of the interfaces defined in
    the Domain layer.
    Can only depend on items in the domain layer.
    

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42. 4 layers of a DDD architecture
    Each bounded context contains:
    ● Domain / Model
    ● Infrastructure
    ● Application
    ● UI
    Provides ‘application services’ to facilitate
    communication to the Domain layer from the UI.
    May call domain services. Cannot contain
    business logic, but can perform validation.
    Can only depend on the domain layer and
    infrastructure layer
    

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43. 4 layers of a DDD architecture
    Each bounded context contains:
    ● Domain / Model
    ● Infrastructure
    ● Application
    ● UI
    UI layer (controllers, console commands, etc)
    Can only talk to the application layer
    

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44. Domain-Driven
    Design
    Getting started
    

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45. 4 layers of a DDD architecture
    Each bounded context contains:
    ● Domain / Model
    ● Infrastructure
    ● Application
    ● UI
    Let’s simplify things by sharing the UI layer across
    contexts
    Symfony’s App namespace is a pre-made UI layer
    we can take advantage of
    We can use Symfony’s controllers and commands
    to keep things feeling familiar
    

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49. Preparation
    

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50. $ symfony new --full \
    absolute-beginners-guide-to-ddd-with-symfony
    

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51. public
    src
    config
    templates
    tests
    composer.json
    

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52. public
    src
    config
    templates
    tests
    composer.json
    Kernel.php
    Controller
    Entity
    Repository
    

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53. public
    src
    config
    App
    templates
    tests
    composer.json
    Kernel.php
    Controller
    Entity
    Repository
    

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54. protected function configureContainer
    (ContainerConfigurator $container
    ): void
    {
    $container
    ->import('../../config/{packages}/*.yaml'
    );
    $container
    ->import('../../config/{packages}/'
    .$this->environment
    .'/*.yaml');
    if (is_file(\dirname(__DIR__).'/../config/services.yaml'
    )) {
    $container
    ->import('../../config/services.yaml'
    );
    $container
    ->import('../../config/{services}_'
    .$this->environment
    .'.yaml');
    } elseif (is_file($path = \dirname(__DIR__).'/../config/services.php'
    )) {
    (require $path)($container
    ->withPath($path), $this);
    }
    }
    protected function configureRoutes
    (RoutingConfigurator $routes): void
    {
    $routes->import('../../config/{routes}/'
    .$this->environment
    .'/*.yaml');
    $routes->import('../../config/{routes}/*.yaml'
    );
    if (is_file(\dirname(__DIR__).'/../config/routes.yaml'
    )) {
    $routes->import('../../config/routes.yaml'
    );
    } elseif (is_file($path = \dirname(__DIR__).'/../config/routes.php'
    )) {
    (require $path)($routes->withPath($path), $this);
    }
    }
    public
    src
    config
    App
    templates
    tests
    composer.json
    Kernel.php
    Controller
    Entity
    Repository
    

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55. "autoload"
    : {
    "psr-4": {
    "App\\": "src/App/"
    }
    },
    public
    src
    config
    App
    templates
    tests
    Kernel.php
    Controller
    Entity
    Repository
    composer.json
    

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56. services:
    # default configuration for services in *this* file
    _defaults:
    autowire: true # Automatically injects dependencies in your services.
    autoconfigure
    : true # Automatically registers your services as commands, event subscribers, etc.
    # makes classes in src/ available to be used as services
    # this creates a service per class whose id is the fully-qualified class name
    App\:
    resource: '../src/
    App/'
    exclude:
    - '../src/
    App/DependencyInjection/'
    - '../src/
    App/Entity/'
    - '../src/
    App/Kernel.php'
    - '../src/
    App/Tests/'
    # controllers are imported separately to make sure services can be injected
    # as action arguments even if you don't extend any base controller class
    App\Controller\
    :
    resource: '../src/
    App/Controller/'
    tags: ['controller.service_arguments']
    public
    src
    config
    App
    templates
    tests
    Kernel.php
    Controller
    Entity
    Repository
    services.yaml
    composer.json
    

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57. doctrine:
    dbal:
    url: '%env(resolve:DATABASE_URL)%'
    # IMPORTANT: You MUST configure your server version,
    # either here or in the DATABASE_URL env var (see .env file)
    #server_version: '5.7'
    orm:
    auto_generate_proxy_classes
    : true
    naming_strategy
    : doctrine.orm.naming_strategy.underscore_number_aware
    auto_mapping
    : true
    mappings:
    App:
    is_bundle: false
    type: annotation
    dir: '%kernel.project_dir%/src/
    App/Entity'
    prefix: 'App\Entity'
    alias: App
    public
    src
    config
    App
    templates
    tests
    Kernel.php
    Controller
    Entity
    Repository
    doctrine.yaml
    composer.json
    packages
    

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58. controllers
    :
    resource: ../../src/
    App/Controller/
    type: annotation
    kernel:
    resource: ../../src/
    App/Kernel.php
    type: annotation
    public
    src
    config
    App
    templates
    tests
    Kernel.php
    Controller
    Entity
    Repository
    annotations.yaml
    composer.json
    routes
    packages
    

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59. The First Bounded Context
    

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60. "autoload"
    : {
    "psr-4": {
    "App\\": "src/App/"
    ,
    "AcmeVet\\"
    : "src/AcmeVet/"
    }
    },
    "autoload-dev"
    : {
    "psr-4": {
    "App\\Tests\\": "tests/"
    }
    },
    public
    src
    config
    AcmeVet
    templates
    tests
    composer.json
    App
    

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61. public
    src
    AcmeVet
    config
    Scheduling
    App
    composer.json
    templates
    tests
    Bounded Context
    

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62. public
    src
    AcmeVet
    config
    Infrastructure
    Scheduling
    Application
    Domain
    App
    composer.json
    templates
    tests
    Bounded Context
    

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63. Build the aggregate
    

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64. public
    src
    AcmeVet
    config
    Scheduling
    Domain
    composer.json
    AppointmentTest.php
    Appointment
    templates
    tests
    

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65. namespace Tests\AcmeVet\Scheduling
    \Domain\Appointment
    ;
    class AppointmentTest extends TestCase
    {
    public function test_an_appointment_can_be_created
    (): void
    {
    }
    public function test_a_double_appointment_can_be_created
    (): void
    {
    }
    public function test_an_appointment_cannot_be_longer_than_a_double_slot
    (): void
    {
    }
    public function test_an_appointment_must_be_longer_than_zero_minutes_long
    (): void
    {
    }
    public function test_an_appointment_must_be_a_multiple_of_fifteen_minutes
    (): void
    {
    }
    }
    public
    src
    AcmeVet
    config
    Scheduling
    Domain
    composer.json
    AppointmentTest.php
    Appointment
    templates
    tests
    

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66. namespace Tests\AcmeVet\Scheduling
    \Domain\Appointment
    ;
    class AppointmentTest extends TestCase
    {
    public function test_an_appointment_can_be_created
    (): void
    {
    $appointmentId = AppointmentId
    ::generate();
    $pet = Pet::create(
    'Luna',
    'David Smith'
    ,
    '07007771234'
    );
    $startTime = new \DateTimeImmutable
    ();
    $appointmentLength = 15;
    $appointment = Appointment
    ::create(
    $appointmentId,
    $pet,
    $startTime,
    $appointmentLength
    );
    static::assertSame
    ($appointmentId, $appointment
    ->getId());
    static::assertSame
    ($pet, $appointment
    ->getPet());
    static::assertSame
    ($startTime, $appointment
    ->getStartTime
    ());
    static::assertSame
    ($appointmentLength, $appointment
    ->getLengthInMinutes
    ());
    }
    }
    public
    src
    AcmeVet
    config
    Scheduling
    Domain
    composer.json
    AppointmentTest.php
    Appointment
    templates
    tests
    

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67. namespace Tests\AcmeVet\Scheduling
    \Domain\Appointment
    ;
    class AppointmentTest extends TestCase
    {
    public function test_an_appointment_can_be_created
    (): void
    {
    $appointmentId = AppointmentId
    ::generate();
    $pet = Pet::create(
    'Luna',
    'David Smith'
    ,
    '07007771234'
    );
    $startTime = new \DateTimeImmutable
    ();
    $appointmentLength = 15;
    $appointment = Appointment
    ::create(
    $appointmentId,
    $pet,
    $startTime,
    $appointmentLength
    );
    static::assertSame
    ($appointmentId, $appointment
    ->getId());
    static::assertSame
    ($pet, $appointment
    ->getPet());
    static::assertSame
    ($startTime, $appointment
    ->getStartTime
    ());
    static::assertSame
    ($appointmentLength, $appointment
    ->getLengthInMinutes
    ());
    }
    }
    public
    src
    AcmeVet
    config
    Scheduling
    Domain
    composer.json
    AppointmentTest.php
    Appointment
    templates
    tests
    

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68. namespace Tests\AcmeVet\Scheduling
    \Domain\Appointment
    ;
    class AppointmentTest extends TestCase
    {
    public function test_an_appointment_can_be_created
    (): void
    {
    $appointmentId = AppointmentId
    ::generate();
    $pet = Pet::create(
    'Luna',
    'David Smith'
    ,
    '07007771234'
    );
    $startTime = new \DateTimeImmutable
    ();
    $appointmentLength = 15;
    $appointment = Appointment
    ::create(
    $appointmentId,
    $pet,
    $startTime,
    $appointmentLength
    );
    static::assertSame
    ($appointmentId, $appointment
    ->getId());
    static::assertSame
    ($pet, $appointment
    ->getPet());
    static::assertSame
    ($startTime, $appointment
    ->getStartTime
    ());
    static::assertSame
    ($appointmentLength, $appointment
    ->getLengthInMinutes
    ());
    }
    }
    public
    src
    AcmeVet
    config
    Scheduling
    Domain
    composer.json
    AppointmentTest.php
    Appointment
    templates
    tests
    

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69. namespace AcmeVet\Scheduling
    \Domain\Appointment
    ;
    use AcmeVet\Appointment
    \Domain\Exception\AppointmentLengthInvalid
    ;
    class Appointment
    {
    private function __construct(
    AppointmentId $appointmentId
    ,
    Pet $pet,
    \DateTimeImmutable $appointmentTime
    ,
    int $appointmentLengthInMinutes
    )
    {
    $this
    ->appointmentId = $appointmentId
    ;
    $this
    ->pet = $pet;
    $this
    ->appointmentTime = $appointmentTime
    ;
    $this
    ->appointmentLengthInMinutes = $appointmentLengthInMinutes
    ;
    }
    }
    public
    src
    AcmeVet
    config
    Infrastructure
    Appointment.php
    Scheduling
    Application
    Domain
    Appointment
    composer.json
    App
    templates
    tests
    Bounded Context
    Aggregate
    Aggregate
    Root
    

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70. public
    src
    AcmeVet
    config
    Infrastructure
    Appointment.php
    namespace AcmeVet\Scheduling
    \Domain\Appointment
    ;
    use AcmeVet\Appointment
    \Domain\Exception\AppointmentLengthInvalid
    ;
    class Appointment
    {
    private function __construct
    (
    AppointmentId $appointmentId
    ,
    Pet $pet,
    \DateTimeImmutable $appointmentTime
    ,
    int $appointmentLengthInMinutes
    )
    {
    $this
    ->appointmentId = $appointmentId
    ;
    $this
    ->pet = $pet;
    $this
    ->appointmentTime = $appointmentTime
    ;
    $this
    ->appointmentLengthInMinutes = $appointmentLengthInMinutes
    ;
    }
    }
    Scheduling
    Application
    Domain
    Appointment
    App
    composer.json
    templates
    tests
    Bounded Context
    Aggregate
    Aggregate
    Root
    

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71. public static function create(
    AppointmentId $appointmentId
    ,
    Pet $pet,
    \DateTimeImmutable $appointmentTime
    ,
    int $appointmentLength
    ): self
    {
    if (self::STANDARD_APPOINTMENT_LENGTH > $appointmentLength
    ) {
    throw new AppointmentLengthInvalid
    (
    sprintf("The minimum appointment length is %s minutes"
    , self::STANDARD_APPOINTMENT_LENGTH
    )
    );
    }
    $maxLength = self::STANDARD_APPOINTMENT_LENGTH * 2;
    if ($maxLength < $appointmentLength
    ) {
    throw new AppointmentLengthInvalid
    (
    sprintf("The maximum appointment length is %s minutes"
    , $maxLength)
    );
    }
    if (0 !== $appointmentLength % self::STANDARD_APPOINTMENT_LENGTH
    ) {
    throw new AppointmentLengthInvalid
    (
    sprintf("The appointment length must be a multiple of %s minutes"
    , self::STANDARD_APPOINTMENT_LENGTH
    )
    );
    }
    return new self
    ($appointmentId
    , $pet, $appointmentTime
    , $appointmentLength
    );
    }
    public
    src
    AcmeVet
    config
    Infrastructure
    Appointment.php
    Scheduling
    Application
    Domain
    Appointment
    composer.json
    App
    templates
    tests
    Bounded Context
    Aggregate
    Aggregate
    Root
    

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72. public static function create(
    AppointmentId $appointmentId
    ,
    Pet $pet,
    \DateTimeImmutable $appointmentTime
    ,
    int $appointmentLength
    ): self
    {
    if (self::STANDARD_APPOINTMENT_LENGTH > $appointmentLength
    ) {
    throw new AppointmentLengthInvalid
    (
    sprintf("The minimum appointment length is %s minutes"
    , self::STANDARD_APPOINTMENT_LENGTH
    )
    );
    }
    $maxLength = self::STANDARD_APPOINTMENT_LENGTH * 2;
    if ($maxLength < $appointmentLength
    ) {
    throw new AppointmentLengthInvalid
    (
    sprintf("The maximum appointment length is %s minutes"
    , $maxLength)
    );
    }
    if (0 !== $appointmentLength % self::STANDARD_APPOINTMENT_LENGTH
    ) {
    throw new AppointmentLengthInvalid
    (
    sprintf("The appointment length must be a multiple of %s minutes"
    , self::STANDARD_APPOINTMENT_LENGTH
    )
    );
    }
    return new self
    ($appointmentId
    , $pet, $appointmentTime
    , $appointmentLength
    );
    }
    public
    src
    AcmeVet
    config
    Infrastructure
    Appointment.php
    Scheduling
    Application
    Domain
    Appointment
    composer.json
    App
    templates
    tests
    Bounded Context
    Aggregate
    Aggregate
    Root
    

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73. public static function create(
    AppointmentId $appointmentId
    ,
    Pet $pet,
    \DateTimeImmutable $appointmentTime
    ,
    int $appointmentLength
    ): self
    {
    if (self::STANDARD_APPOINTMENT_LENGTH > $appointmentLength
    ) {
    throw new AppointmentLengthInvalid
    (
    sprintf("The minimum appointment length is %s minutes"
    , self::STANDARD_APPOINTMENT_LENGTH
    )
    );
    }
    $maxLength = self::STANDARD_APPOINTMENT_LENGTH * 2;
    if ($maxLength < $appointmentLength
    ) {
    throw new AppointmentLengthInvalid
    (
    sprintf("The maximum appointment length is %s minutes"
    , $maxLength)
    );
    }
    if (0 !== $appointmentLength % self::STANDARD_APPOINTMENT_LENGTH
    ) {
    throw new AppointmentLengthInvalid
    (
    sprintf("The appointment length must be a multiple of %s minutes"
    , self::STANDARD_APPOINTMENT_LENGTH
    )
    );
    }
    return new self
    ($appointmentId
    , $pet, $appointmentTime
    , $appointmentLength
    );
    }
    public
    src
    AcmeVet
    config
    Infrastructure
    Appointment.php
    Scheduling
    Application
    Domain
    Appointment
    composer.json
    App
    templates
    tests
    Bounded Context
    Aggregate
    Aggregate
    Root
    

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74. public static function create(
    AppointmentId $appointmentId
    ,
    Pet $pet,
    \DateTimeImmutable $appointmentTime
    ,
    int $appointmentLength
    ): self
    {
    if (self::STANDARD_APPOINTMENT_LENGTH > $appointmentLength
    ) {
    throw new AppointmentLengthInvalid
    (
    sprintf("The minimum appointment length is %s minutes"
    , self::STANDARD_APPOINTMENT_LENGTH
    )
    );
    }
    $maxLength = self::STANDARD_APPOINTMENT_LENGTH * 2;
    if ($maxLength < $appointmentLength
    ) {
    throw new AppointmentLengthInvalid
    (
    sprintf("The maximum appointment length is %s minutes"
    , $maxLength)
    );
    }
    if (0 !== $appointmentLength % self::STANDARD_APPOINTMENT_LENGTH
    ) {
    throw new AppointmentLengthInvalid
    (
    sprintf("The appointment length must be a multiple of %s minutes"
    , self::STANDARD_APPOINTMENT_LENGTH
    )
    );
    }
    return new self
    ($appointmentId
    , $pet, $appointmentTime
    , $appointmentLength
    );
    }
    public
    src
    AcmeVet
    config
    Infrastructure
    Appointment.php
    Scheduling
    Application
    Domain
    Appointment
    composer.json
    App
    templates
    tests
    Bounded Context
    Aggregate
    Aggregate
    Root
    

    View Slide

75. public static function create(
    AppointmentId $appointmentId
    ,
    Pet $pet,
    \DateTimeImmutable $appointmentTime
    ,
    int $appointmentLength
    ): self
    {
    if (self::STANDARD_APPOINTMENT_LENGTH > $appointmentLength
    ) {
    throw new AppointmentLengthInvalid
    (
    sprintf("The minimum appointment length is %s minutes"
    , self::STANDARD_APPOINTMENT_LENGTH
    )
    );
    }
    $maxLength = self::STANDARD_APPOINTMENT_LENGTH * 2;
    if ($maxLength < $appointmentLength
    ) {
    throw new AppointmentLengthInvalid
    (
    sprintf("The maximum appointment length is %s minutes"
    , $maxLength)
    );
    }
    if (0 !== $appointmentLength % self::STANDARD_APPOINTMENT_LENGTH
    ) {
    throw new AppointmentLengthInvalid
    (
    sprintf("The appointment length must be a multiple of %s minutes"
    , self::STANDARD_APPOINTMENT_LENGTH
    )
    );
    }
    return new self
    ($appointmentId
    , $pet, $appointmentTime
    , $appointmentLength
    );
    }
    public
    src
    AcmeVet
    config
    Infrastructure
    Appointment.php
    Scheduling
    Application
    Domain
    Appointment
    composer.json
    App
    templates
    tests
    Bounded Context
    Aggregate
    Aggregate
    Root
    

    View Slide

76. public static function create(
    AppointmentId $appointmentId
    ,
    Pet $pet,
    \DateTimeImmutable $appointmentTime
    ,
    int $appointmentLength
    ): self
    {
    if (self::STANDARD_APPOINTMENT_LENGTH > $appointmentLength
    ) {
    throw new AppointmentLengthInvalid
    (
    sprintf("The minimum appointment length is %s minutes"
    , self::STANDARD_APPOINTMENT_LENGTH
    )
    );
    }
    $maxLength = self::STANDARD_APPOINTMENT_LENGTH * 2;
    if ($maxLength < $appointmentLength
    ) {
    throw new AppointmentLengthInvalid
    (
    sprintf("The maximum appointment length is %s minutes"
    , $maxLength)
    );
    }
    if (0 !== $appointmentLength % self::STANDARD_APPOINTMENT_LENGTH
    ) {
    throw new AppointmentLengthInvalid
    (
    sprintf("The appointment length must be a multiple of %s minutes"
    , self::STANDARD_APPOINTMENT_LENGTH
    )
    );
    }
    return new self
    ($appointmentId
    , $pet, $appointmentTime
    , $appointmentLength
    );
    }
    public
    src
    AcmeVet
    config
    Infrastructure
    Appointment.php
    Scheduling
    Application
    Domain
    Appointment
    composer.json
    App
    templates
    tests
    Bounded Context
    Aggregate
    Aggregate
    Root
    

    View Slide

77. namespace AcmeVet\Scheduling
    \Domain\Appointment
    ;
    use Ramsey\Uuid\Uuid;
    class AppointmentId
    {
    private string $id;
    private function __construct
    (string $id)
    {
    $this
    ->id = $id;
    }
    public static function generate(): self
    {
    return new self
    (Uuid::uuid4()->toString());
    }
    public static function fromString
    (string $id): self
    {
    if (false === Uuid::isValid($id)) {
    throw new \DomainException
    (
    \sprintf("AppointmentId '%s' is not valid"
    , $id)
    );
    }
    return new self
    ($id);
    }
    public function toString(): string
    {
    return $this->id;
    }
    }
    public
    src
    AcmeVet
    config
    Infrastructure
    Scheduling
    Application
    Domain
    Appointment
    composer.json
    AppointmentId.php
    Appointment.php
    App
    templates
    tests
    Bounded Context
    Aggregate
    Aggregate
    Root
    

    View Slide

78. namespace AcmeVet\Scheduling
    \Domain\Appointment
    ;
    use Ramsey\Uuid\Uuid;
    class AppointmentId
    {
    private string $id;
    private function __construct
    (string $id)
    {
    $this
    ->id = $id;
    }
    public static function generate(): self
    {
    return new self
    (Uuid::uuid4()->toString());
    }
    public static function fromString
    (string $id): self
    {
    if (false === Uuid::isValid($id)) {
    throw new \DomainException
    (
    \sprintf("AppointmentId '%s' is not valid"
    , $id)
    );
    }
    return new self
    ($id);
    }
    public function toString(): string
    {
    return $this->id;
    }
    }
    public
    src
    AcmeVet
    config
    Infrastructure
    Scheduling
    Application
    Domain
    Appointment
    composer.json
    AppointmentId.php
    Appointment.php
    App
    templates
    tests
    Bounded Context
    Aggregate
    Aggregate
    Root
    

    View Slide

79. class Pet
    {
    private string $name;
    private string $ownerName
    ;
    private string $contactNumber
    ;
    private function __construct
    (
    string $name,
    string $ownerName
    ,
    string $contactNumber
    ) {
    $this
    ->name = $name;
    $this
    ->ownerName = $ownerName
    ;
    $this
    ->contactNumber = $contactNumber
    ;
    }
    public static function create(
    string $name,
    string $ownerName
    ,
    string $contactNumber
    ) {
    return new self
    ($name, $ownerName
    , $contactNumber
    );
    }
    public function getName(): string
    {
    return $this->name;
    }
    public function getOwnerName
    (): string
    {
    return $this->ownerName;
    }
    public function getContactNumber
    (): string
    {
    return $this->contactNumber
    ;
    }
    }
    public
    src
    AcmeVet
    config
    Infrastructure
    Scheduling
    Application
    Domain
    composer.json
    AppointmentId.php
    Pet.php
    Appointment.php
    App
    templates
    tests
    Appointment
    Bounded Context
    Aggregate
    Aggregate
    Root
    

    View Slide

80. namespace AcmeVet\Scheduling
    \Domain\Appointment
    \Exception;
    class AppointmentLengthInvalid extends \DomainException
    {
    }
    public
    src
    AcmeVet
    config
    Infrastructure
    Scheduling
    Application
    Domain
    Exception
    composer.json
    AppointmentId.php
    Pet.php
    Appointment.php
    AppointmentLengthInvalid.php
    App
    templates
    tests
    Appointment
    Bounded Context
    Aggregate
    Aggregate
    Root
    

    View Slide

81. Create a domain service
    

    View Slide

82. namespace AcmeVet\Scheduling
    \Domain\Appointment
    ;
    namespace AcmeVet\Scheduling
    \Domain\Appointment
    \Exception\CouldNotConfirmSlotException
    ;
    class SlotConfirmationService
    {
    private AppointmentRepository $appointmentRepository
    ;
    public function __construct
    (
    AppointmentRepository $appointmentRepository
    ) {
    $this
    ->appointmentRepository = $appointmentRepository
    ;
    }
    public function confirmSlot
    (Appointment $appointment
    ): void
    {
    $this
    ->checkStartTimeIsNotInThePast
    ($appointment
    );
    $this
    ->checkSlotStartTimeIsNotTaken
    ($appointment
    );
    $this
    ->checkSlotIsNotTakenByADoubleLengthBooking
    ($appointment
    );
    $this
    ->checkSlotDoesNotSpanAnotherBooking
    ($appointment
    );
    $this
    ->appointmentRepository
    ->store($appointment
    );
    }
    private function checkStartTimeIsNotInThePast
    (Appointment $appointment
    ): void
    {
    $dateDiff = $appointment
    ->getStartTime
    ()->diff(new \DateTimeImmutable
    ());
    if (
    $appointment
    ->getStartTime
    () < new \DateTimeImmutable
    ()
    && 0 !== (int) $dateDiff->format('%y%m%d%h%i'
    )
    ) {
    throw new CouldNotConfirmSlotException
    ("The slot must not be in the past"
    );
    }
    }
    public
    src
    AcmeVet
    config
    Infrastructure
    Scheduling
    Application
    Domain
    Exception
    composer.json
    AppointmentId.php
    Pet.php
    Appointment.php
    SlotConfirmationService.php
    Appointment
    App
    templates
    tests
    Bounded Context
    Aggregate
    Aggregate
    Root
    

    View Slide

83. namespace AcmeVet\Scheduling
    \Domain\Appointment
    ;
    namespace AcmeVet\Scheduling
    \Domain\Appointment
    \Exception\CouldNotConfirmSlotException
    ;
    class SlotConfirmationService
    {
    private AppointmentRepository $appointmentRepository
    ;
    public function __construct
    (
    AppointmentRepository $appointmentRepository
    ) {
    $this
    ->appointmentRepository = $appointmentRepository
    ;
    }
    public function confirmSlot
    (Appointment $appointment
    ): void
    {
    $this
    ->checkStartTimeIsNotInThePast
    ($appointment
    );
    $this
    ->checkSlotStartTimeIsNotTaken
    ($appointment
    );
    $this
    ->checkSlotIsNotTakenByADoubleLengthBooking
    ($appointment
    );
    $this
    ->checkSlotDoesNotSpanAnotherBooking
    ($appointment
    );
    $this
    ->appointmentRepository
    ->store($appointment
    );
    }
    private function checkStartTimeIsNotInThePast
    (Appointment $appointment
    ): void
    {
    $dateDiff = $appointment
    ->getStartTime
    ()->diff(new \DateTimeImmutable
    ());
    if (
    $appointment
    ->getStartTime
    () < new \DateTimeImmutable
    ()
    && 0 !== (int) $dateDiff->format('%y%m%d%h%i'
    )
    ) {
    throw new CouldNotConfirmSlotException
    ("The slot must not be in the past"
    );
    }
    }
    public
    src
    AcmeVet
    config
    Infrastructure
    Scheduling
    Application
    Domain
    Exception
    composer.json
    AppointmentId.php
    Pet.php
    Appointment.php
    SlotConfirmationService.php
    Appointment
    App
    templates
    tests
    Bounded Context
    Aggregate
    Aggregate
    Root
    

    View Slide

84. namespace AcmeVet\Scheduling
    \Domain\Appointment
    ;
    namespace AcmeVet\Scheduling
    \Domain\Appointment
    \Exception\CouldNotConfirmSlotException
    ;
    class SlotConfirmationService
    {
    private AppointmentRepository $appointmentRepository
    ;
    public function __construct
    (
    AppointmentRepository $appointmentRepository
    ) {
    $this
    ->appointmentRepository = $appointmentRepository
    ;
    }
    public function confirmSlot
    (Appointment $appointment
    ): void
    {
    $this
    ->checkStartTimeIsNotInThePast
    ($appointment
    );
    $this
    ->checkSlotStartTimeIsNotTaken
    ($appointment
    );
    $this
    ->checkSlotIsNotTakenByADoubleLengthBooking
    ($appointment
    );
    $this
    ->checkSlotDoesNotSpanAnotherBooking
    ($appointment
    );
    $this
    ->appointmentRepository
    ->store($appointment
    );
    }
    private function checkStartTimeIsNotInThePast
    (Appointment $appointment
    ): void
    {
    $dateDiff = $appointment
    ->getStartTime
    ()->diff(new \DateTimeImmutable
    ());
    if (
    $appointment
    ->getStartTime
    () < new \DateTimeImmutable
    ()
    && 0 !== (int) $dateDiff->format('%y%m%d%h%i'
    )
    ) {
    throw new CouldNotConfirmSlotException
    ("The slot must not be in the past"
    );
    }
    }
    public
    src
    AcmeVet
    config
    Infrastructure
    Scheduling
    Application
    Domain
    Exception
    composer.json
    AppointmentId.php
    Pet.php
    Appointment.php
    SlotConfirmationService.php
    Appointment
    App
    templates
    tests
    Bounded Context
    Aggregate
    Aggregate
    Root
    

    View Slide

85. namespace AcmeVet\Scheduling
    \Domain\Appointment
    ;
    namespace AcmeVet\Scheduling
    \Domain\Appointment
    \Exception\CouldNotConfirmSlotException
    ;
    class SlotConfirmationService
    {
    private AppointmentRepository $appointmentRepository
    ;
    public function __construct
    (
    AppointmentRepository $appointmentRepository
    ) {
    $this
    ->appointmentRepository = $appointmentRepository
    ;
    }
    public function confirmSlot
    (Appointment $appointment
    ): void
    {
    $this
    ->checkStartTimeIsNotInThePast
    ($appointment
    );
    $this
    ->checkSlotStartTimeIsNotTaken
    ($appointment
    );
    $this
    ->checkSlotIsNotTakenByADoubleLengthBooking
    ($appointment
    );
    $this
    ->checkSlotDoesNotSpanAnotherBooking
    ($appointment
    );
    $this
    ->appointmentRepository
    ->store($appointment
    );
    }
    private function checkStartTimeIsNotInThePast
    (Appointment $appointment
    ): void
    {
    $dateDiff = $appointment
    ->getStartTime
    ()->diff(new \DateTimeImmutable
    ());
    if (
    $appointment
    ->getStartTime
    () < new \DateTimeImmutable
    ()
    && 0 !== (int) $dateDiff->format('%y%m%d%h%i'
    )
    ) {
    throw new CouldNotConfirmSlotException
    ("The slot must not be in the past"
    );
    }
    }
    public
    src
    AcmeVet
    config
    Infrastructure
    Scheduling
    Application
    Domain
    Exception
    composer.json
    AppointmentId.php
    Pet.php
    Appointment.php
    SlotConfirmationService.php
    Appointment
    App
    templates
    tests
    Bounded Context
    Aggregate
    Aggregate
    Root
    

    View Slide

86. namespace AcmeVet\Scheduling
    \Domain\Appointment
    ;
    interface AppointmentRepository
    {
    public function getAppointmentAtTime
    (\DateTimeImmutable $appointmentTime
    ): ?Appointment
    ;
    public function store(Appointment $appointment
    ): void;
    /**
    * @return Appointment[]
    */
    public function getAll(): array;
    }
    public
    src
    AcmeVet
    config
    Infrastructure
    Scheduling
    Application
    Domain
    Exception
    composer.json
    AppointmentId.php
    Pet.php
    Appointment.php
    AppointmentRepository.php
    Appointment
    SlotConfirmationService.php
    App
    templates
    tests
    Bounded Context
    Aggregate
    Aggregate
    Root
    

    View Slide

87. namespace AcmeVet\Scheduling
    \Domain\Appointment
    ;
    interface AppointmentRepository
    {
    public function getAppointmentAtTime
    (\DateTimeImmutable $appointmentTime
    ): ?Appointment
    ;
    public function store(Appointment $appointment
    ): void;
    /**
    * @return Appointment[]
    */
    public function getAll(): array;
    }
    public
    src
    AcmeVet
    config
    Infrastructure
    Scheduling
    Application
    Domain
    Exception
    composer.json
    AppointmentId.php
    Pet.php
    Appointment.php
    AppointmentRepository.php
    Appointment
    SlotConfirmationService.php
    App
    templates
    tests
    Bounded Context
    Aggregate
    Aggregate
    Root
    

    View Slide

88. namespace AcmeVet\Scheduling
    \Domain\Appointment
    ;
    interface AppointmentRepository
    {
    public function getAppointmentAtTime
    (\DateTimeImmutable $appointmentTime
    ): ?Appointment
    ;
    public function store(Appointment $appointment
    ): void;
    /**
    * @return Appointment[]
    */
    public function getAll(): array;
    }
    public
    src
    AcmeVet
    config
    Infrastructure
    Scheduling
    Application
    Domain
    Exception
    composer.json
    AppointmentId.php
    Pet.php
    Appointment.php
    AppointmentRepository.php
    Appointment
    SlotConfirmationService.php
    App
    templates
    tests
    Bounded Context
    Aggregate
    Aggregate
    Root
    

    View Slide

89. namespace Tests\AcmeVet\Scheduling
    \Domain\Appointment
    ;
    class SlotConfirmationServiceTest extends TestCase
    {
    public function test_a_slot_can_be_confirmed
    (): void
    {
    $repository = new InMemoryAppointmentRepository
    ();
    $service = new SlotConfirmationService
    ($repository);
    $dateTime = new \DateTimeImmutable
    ();
    $appointment = Appointment
    ::create(
    AppointmentId
    ::generate(),
    Pet::create('Luna', 'David Smith'
    , '07500777123'
    ),
    $dateTime,
    15
    );
    $service
    ->confirmSlot
    ($appointment);
    static::assertSame
    (
    $appointment,
    $repository
    ->getAppointmentAtTime
    ($dateTime)
    );
    }
    public function test_an_appointment_cannot_be_made_in_the_past
    (): void
    {
    }
    public
    src
    AcmeVet
    config
    Scheduling
    Domain
    templates
    tests
    composer.json
    SlotConfirmationServiceTest.php
    Appointment
    AppointmentTest.php
    

    View Slide

90. namespace Tests\AcmeVet\Scheduling
    \Domain\Appointment
    ;
    class SlotConfirmationServiceTest extends TestCase
    {
    public function test_a_slot_can_be_confirmed
    (): void
    {
    $repository = new InMemoryAppointmentRepository
    ();
    $service = new SlotConfirmationService
    ($repository);
    $dateTime = new \DateTimeImmutable
    ();
    $appointment = Appointment
    ::create(
    AppointmentId
    ::generate(),
    Pet::create('Luna', 'David Smith'
    , '07500777123'
    ),
    $dateTime,
    15
    );
    $service
    ->confirmSlot
    ($appointment);
    static::assertSame
    (
    $appointment,
    $repository
    ->getAppointmentAtTime
    ($dateTime)
    );
    }
    public function test_an_appointment_cannot_be_made_in_the_past
    (): void
    {
    }
    public
    src
    AcmeVet
    config
    Scheduling
    Domain
    composer.json
    SlotConfirmationServiceTest.php
    Appointment
    AppointmentTest.php
    templates
    tests
    

    View Slide

91. namespace Tests\AcmeVet\Scheduling
    \Doubles;
    use AcmeVet\Appointment
    \Domain\Appointment
    ;
    use AcmeVet\Appointment
    \Domain\AppointmentRepository
    ;
    class InMemoryAppointmentRepository implements AppointmentRepository
    {
    private array $appointments = [];
    public function getAppointmentAtTime
    (
    \DateTimeImmutable $appointmentTime
    ): ?Appointment {
    // …
    }
    public function store(Appointment $appointment
    ): void
    {
    $this
    ->appointments
    [] = $appointment
    ;
    }
    public function getAll(): array
    {
    return $this->appointments
    ;
    }
    }
    public
    src
    AcmeVet
    config
    Scheduling
    Domain
    composer.json
    InMemoryAppointmentRepository.php
    Appointment
    AppointmentTest.php
    Doubles
    SlotConfirmationService.php
    templates
    tests
    

    View Slide

92. Infrastructure
    

    View Slide

93. namespace AcmeVet\Scheduling
    \Infrastructure
    ;
    use AcmeVet\Scheduling
    \Domain\Appointment
    \Appointment
    ;
    use AcmeVet\Scheduling
    \Domain\Appointment
    \AppointmentId
    ;
    use AcmeVet\Scheduling
    \Domain\Appointment
    \AppointmentRepository
    ;
    use AcmeVet\Scheduling
    \Domain\Appointment
    \Pet;
    use Doctrine\DBAL\Connection
    ;
    class DbalAppointmentRepository implements AppointmentRepository
    {
    private const DATE_FORMAT = "Y-m-d\TH:i"
    ;
    private Connection $connection
    ;
    public function __construct
    (Connection $connection
    )
    {
    $this
    ->connection = $connection
    ;
    }
    public function getAppointmentAtTime
    (
    \DateTimeImmutable $appointmentTime
    ): ?Appointment {
    $stmt = $this->connection
    ->prepare('
    SELECT * FROM appointments WHERE start_time = :start_time
    ');
    $stmt
    ->bindValue('start_time'
    , $appointmentTime
    ->format(self::DATE_FORMAT
    ));
    $stmt
    ->execute();
    }
    public
    src
    AcmeVet
    config
    Infrastructure
    Scheduling
    Application
    Domain
    composer.json
    DbalAppointmentRepository.php
    App
    templates
    tests
    Bounded Context
    

    View Slide

94. namespace AcmeVet\Scheduling
    \Infrastructure
    ;
    use AcmeVet\Scheduling
    \Domain\Appointment
    \Appointment
    ;
    use AcmeVet\Scheduling
    \Domain\Appointment
    \AppointmentId
    ;
    use AcmeVet\Scheduling
    \Domain\Appointment
    \AppointmentRepository
    ;
    use AcmeVet\Scheduling
    \Domain\Appointment
    \Pet;
    use Doctrine\DBAL\Connection
    ;
    class DbalAppointmentRepository implements AppointmentRepository
    {
    private const DATE_FORMAT = "Y-m-d\TH:i"
    ;
    private Connection $connection
    ;
    public function __construct
    (Connection $connection
    )
    {
    $this
    ->connection = $connection
    ;
    }
    public function getAppointmentAtTime
    (
    \DateTimeImmutable $appointmentTime
    ): ?Appointment {
    $stmt = $this->connection
    ->prepare('
    SELECT * FROM appointments WHERE start_time = :start_time
    ');
    $stmt
    ->bindValue('start_time'
    , $appointmentTime
    ->format(self::DATE_FORMAT
    ));
    $stmt
    ->execute();
    }
    public
    src
    AcmeVet
    config
    Infrastructure
    Scheduling
    Application
    Domain
    DbalAppointmentRepository.php
    composer.json
    App
    templates
    tests
    Bounded Context
    

    View Slide

95. namespace AcmeVet\Scheduling
    \Infrastructure
    ;
    use AcmeVet\Scheduling
    \Domain\Appointment
    \Appointment
    ;
    use AcmeVet\Scheduling
    \Domain\Appointment
    \AppointmentId
    ;
    use AcmeVet\Scheduling
    \Domain\Appointment
    \AppointmentRepository
    ;
    use AcmeVet\Scheduling
    \Domain\Appointment
    \Pet;
    use Doctrine\DBAL\Connection
    ;
    class DbalAppointmentRepository implements AppointmentRepository
    {
    private const DATE_FORMAT = "Y-m-d\TH:i"
    ;
    private Connection $connection
    ;
    public function __construct
    (Connection $connection
    )
    {
    $this
    ->connection = $connection
    ;
    }
    public function getAppointmentAtTime
    (
    \DateTimeImmutable $appointmentTime
    ): ?Appointment {
    $stmt = $this->connection
    ->prepare('
    SELECT * FROM appointments WHERE start_time = :start_time
    ');
    $stmt
    ->bindValue('start_time'
    , $appointmentTime
    ->format(self::DATE_FORMAT
    ));
    $stmt
    ->execute();
    }
    public
    src
    AcmeVet
    config
    Infrastructure
    Scheduling
    Application
    Domain
    DbalAppointmentRepository.php
    composer.json
    App
    templates
    tests
    Bounded Context
    

    View Slide

96. namespace AcmeVet\Scheduling
    \Infrastructure
    ;
    use AcmeVet\Scheduling
    \Domain\Appointment
    \Appointment
    ;
    use AcmeVet\Scheduling
    \Domain\Appointment
    \AppointmentId
    ;
    use AcmeVet\Scheduling
    \Domain\Appointment
    \AppointmentRepository
    ;
    use AcmeVet\Scheduling
    \Domain\Appointment
    \Pet;
    use Doctrine\DBAL\Connection
    ;
    class DbalAppointmentRepository implements AppointmentRepository
    {
    private const DATE_FORMAT = "Y-m-d\TH:i"
    ;
    private Connection $connection
    ;
    public function __construct
    (Connection $connection
    )
    {
    $this
    ->connection = $connection
    ;
    }
    public function getAppointmentAtTime
    (
    \DateTimeImmutable $appointmentTime
    ): ?Appointment {
    $stmt = $this->connection
    ->prepare('
    SELECT * FROM appointments WHERE start_time = :start_time
    ');
    $stmt
    ->bindValue('start_time'
    , $appointmentTime
    ->format(self::DATE_FORMAT
    ));
    $stmt
    ->execute();
    }
    public
    src
    AcmeVet
    config
    Infrastructure
    Scheduling
    Application
    Domain
    DbalAppointmentRepository.php
    composer.json
    App
    templates
    tests
    Bounded Context
    

    View Slide

97. public function getAppointmentAtTime
    (
    \DateTimeImmutable $appointmentTime
    ): ?Appointment {
    $stmt = $this->connection
    ->prepare('
    SELECT * FROM appointments WHERE start_time = :start_time
    ');
    $stmt
    ->bindValue('start_time'
    , $appointmentTime
    ->format(self::DATE_FORMAT
    ));
    $stmt
    ->execute();
    $result = $stmt->fetchAssociative
    ();
    if (!$result) {
    return null
    ;
    }
    return Appointment
    ::create(
    AppointmentId
    ::fromString
    ($result['id']),
    Pet::create(
    $result[
    'pet_name'
    ],
    $result[
    'owner_name'
    ],
    $result[
    'contact_number'
    ]
    ),
    \DateTimeImmutable
    ::createFromFormat
    (
    self::DATE_FORMAT
    ,
    $result['start_time'
    ]
    ),
    $result[
    'length']
    );
    }
    public
    src
    AcmeVet
    config
    Infrastructure
    Scheduling
    Application
    Domain
    DbalAppointmentRepository.php
    composer.json
    App
    templates
    tests
    Bounded Context
    

    View Slide

98. services:
    # ...
    # Tell Symfony to auto-wire everything that it finds
    # within the AcmeVet namespace
    AcmeVet\
    :
    resource: '../src/AcmeVet/'
    public
    src
    AcmeVet
    config
    Infrastructure
    Scheduling
    Application
    Domain
    DbalAppointmentRepository.php
    services.yaml
    composer.json
    App
    templates
    tests
    Bounded Context
    

    View Slide

99. $ php bin/console doctrine:migrations:generate
    

    View Slide

100. namespace DoctrineMigrations
     ;
     use Doctrine\DBAL\Schema\Schema;
     use Doctrine\Migrations
     \AbstractMigration
     ;
     final class Version20201107141910 extends AbstractMigration
     {
     public function getDescription
     () : string
     {
     return 'Add the table for appointments in the
     AcmeVet\Appointment context'
     ;
     }
     public function up(Schema $schema) : void
     {
     $this
     ->addSql('
     CREATE TABLE appointments (
     id CHARACTER(36) PRIMARY KEY,
     start_time VARCHAR,
     length CHARACTER(2),
     pet_name VARCHAR,
     owner_name VARCHAR,
     contact_number VARCHAR
     )
     ');
     }
     public function down(Schema $schema): void
     {
     $this
     ->addSql('DROP TABLE appointments'
     );
     }
     }
     public
     src
     AcmeVet
     config
     Infrastructure
     Scheduling
     Application
     Domain
     DbalAppointmentRepository.php
     Version2020110714910.php
     migrations
     composer.json
     App
     templates
     tests
     Bounded Context
     

     View Slide

101. Application services
     

     View Slide

102. View Slide

103. class AppointmentBookingCommand implements Command
     {
     private \DateTimeImmutable $appointmentTime
     ;
     private string $petName;
     private string $ownerName
     ;
     private string $contactNumber
     ;
     private int $appointmentLengthInMinutes
     ;
     public function __construct
     (
     \DateTimeImmutable $appointmentTime
     ,
     string $petName,
     string $ownerName
     ,
     string $contactNumber
     ,
     int $appointmentLengthInMinutes
     )
     {
     $this
     ->appointmentTime = $appointmentTime
     ;
     $this
     ->petName = $petName;
     $this
     ->ownerName = $ownerName
     ;
     $this
     ->contactNumber = $contactNumber
     ;
     $this
     ->appointmentLengthInMinutes = $appointmentLengthInMinutes
     ;
     }
     public function getAppointmentTime
     (): \DateTimeImmutable
     {
     return $this->appointmentTime
     ;
     }
     public function getPetName
     (): string
     {
     return $this->petName;
     }
     public function getOwnerName
     (): string
     {
     return $this->ownerName;
     }
     public function getContactNumber
     (): string
     {
     return $this->contactNumber
     ;
     }
     public function getAppointmentLengthInMinutes
     (): int
     {
     return $this->appointmentLengthInMinutes
     ;
     }
     }
     public
     src
     AcmeVet
     config
     Infrastructure
     Scheduling
     Application
     Domain
     AppointmentBookingCommand.php
     Command
     Booking
     migrations
     composer.json
     App
     templates
     tests
     Bounded Context
     

     View Slide

104. class AppointmentBookingCommand implements Command
     {
     private \DateTimeImmutable $appointmentTime
     ;
     private string $petName;
     private string $ownerName
     ;
     private string $contactNumber
     ;
     private int $appointmentLengthInMinutes
     ;
     public function __construct
     (
     \DateTimeImmutable $appointmentTime
     ,
     string $petName,
     string $ownerName
     ,
     string $contactNumber
     ,
     int $appointmentLengthInMinutes
     )
     {
     $this
     ->appointmentTime = $appointmentTime
     ;
     $this
     ->petName = $petName;
     $this
     ->ownerName = $ownerName
     ;
     $this
     ->contactNumber = $contactNumber
     ;
     $this
     ->appointmentLengthInMinutes = $appointmentLengthInMinutes
     ;
     }
     public function getAppointmentTime
     (): \DateTimeImmutable
     {
     return $this->appointmentTime
     ;
     }
     public function getPetName
     (): string
     {
     return $this->petName;
     }
     public function getOwnerName
     (): string
     {
     return $this->ownerName;
     }
     public function getContactNumber
     (): string
     {
     return $this->contactNumber
     ;
     }
     public function getAppointmentLengthInMinutes
     (): int
     {
     return $this->appointmentLengthInMinutes
     ;
     }
     }
     public
     src
     AcmeVet
     config
     Infrastructure
     Scheduling
     Application
     Domain
     AppointmentBookingCommand.php
     Command
     Booking
     migrations
     composer.json
     App
     templates
     tests
     Bounded Context
     

     View Slide

105. class AppointmentBookingHandler implements Handler
     {
     private SlotConfirmationService $slotConfirmationService
     ;
     public function __construct
     (
     SlotConfirmationService $slotConfirmationService
     ) {
     $this
     ->slotConfirmationService = $slotConfirmationService
     ;
     }
     public function __invoke(Command $command): void
     {
     $appointment = Appointment
     ::create(
     AppointmentId
     ::generate(),
     Pet::create(
     $command->getPetName
     (),
     $command->getOwnerName
     (),
     $command->getContactNumber
     ()
     ),
     $command->getAppointmentTime
     (),
     $command->getAppointmentLengthInMinutes
     ()
     );
     try {
     $this
     ->slotConfirmationService
     ->confirmSlot
     ($appointment);
     } catch (CouldNotConfirmSlotException $exception) {
     throw new \RuntimeException
     ("The slot could not be booked"
     );
     }
     }
     }
     public
     src
     AcmeVet
     config
     Infrastructure
     Scheduling
     Application
     Domain
     AppointmentBookingCommand.php
     Command
     Booking
     AppointmentBookingHandler.php
     migrations
     composer.json
     App
     templates
     tests
     Bounded Context
     

     View Slide

106. class AppointmentBookingHandler implements Handler
     {
     private SlotConfirmationService $slotConfirmationService
     ;
     public function __construct
     (
     SlotConfirmationService $slotConfirmationService
     ) {
     $this
     ->slotConfirmationService = $slotConfirmationService
     ;
     }
     public function __invoke(Command $command): void
     {
     $appointment = Appointment
     ::create(
     AppointmentId
     ::generate(),
     Pet::create(
     $command->getPetName
     (),
     $command->getOwnerName
     (),
     $command->getContactNumber
     ()
     ),
     $command->getAppointmentTime
     (),
     $command->getAppointmentLengthInMinutes
     ()
     );
     try {
     $this
     ->slotConfirmationService
     ->confirmSlot
     ($appointment);
     } catch (CouldNotConfirmSlotException $exception) {
     throw new \RuntimeException
     ("The slot could not be booked"
     );
     }
     }
     }
     public
     src
     AcmeVet
     config
     Infrastructure
     Scheduling
     Application
     Domain
     AppointmentBookingCommand.php
     Command
     Booking
     AppointmentBookingHandler.php
     migrations
     composer.json
     App
     templates
     tests
     Bounded Context
     

     View Slide

107. class AppointmentBookingHandler implements Handler
     {
     private SlotConfirmationService $slotConfirmationService
     ;
     public function __construct
     (
     SlotConfirmationService $slotConfirmationService
     ) {
     $this
     ->slotConfirmationService = $slotConfirmationService
     ;
     }
     public function __invoke(Command $command): void
     {
     $appointment = Appointment
     ::create(
     AppointmentId
     ::generate(),
     Pet::create(
     $command->getPetName
     (),
     $command->getOwnerName
     (),
     $command->getContactNumber
     ()
     ),
     $command->getAppointmentTime
     (),
     $command->getAppointmentLengthInMinutes
     ()
     );
     try {
     $this
     ->slotConfirmationService
     ->confirmSlot
     ($appointment);
     } catch (CouldNotConfirmSlotException $exception) {
     throw new \RuntimeException
     ("The slot could not be booked"
     );
     }
     }
     }
     public
     src
     AcmeVet
     config
     Infrastructure
     Scheduling
     Application
     Domain
     AppointmentBookingCommand.php
     Command
     Booking
     AppointmentBookingHandler.php
     migrations
     composer.json
     App
     templates
     tests
     Bounded Context
     

     View Slide

108. class AppointmentBookingHandler implements Handler
     {
     private SlotConfirmationService $slotConfirmationService
     ;
     public function __construct
     (
     SlotConfirmationService $slotConfirmationService
     ) {
     $this
     ->slotConfirmationService = $slotConfirmationService
     ;
     }
     public function __invoke(Command $command): void
     {
     $appointment = Appointment
     ::create(
     AppointmentId
     ::generate(),
     Pet::create(
     $command->getPetName
     (),
     $command->getOwnerName
     (),
     $command->getContactNumber
     ()
     ),
     $command->getAppointmentTime
     (),
     $command->getAppointmentLengthInMinutes
     ()
     );
     try {
     $this
     ->slotConfirmationService
     ->confirmSlot
     ($appointment);
     } catch (CouldNotConfirmSlotException $exception) {
     throw new \RuntimeException
     ("The slot could not be booked"
     );
     }
     }
     }
     public
     src
     AcmeVet
     config
     Infrastructure
     Scheduling
     Application
     Domain
     AppointmentBookingCommand.php
     Command
     Booking
     AppointmentBookingHandler.php
     migrations
     composer.json
     App
     templates
     tests
     Bounded Context
     

     View Slide

109. class AppointmentBookingHandler implements Handler
     {
     private SlotConfirmationService $slotConfirmationService
     ;
     public function __construct
     (
     SlotConfirmationService $slotConfirmationService
     ) {
     $this
     ->slotConfirmationService = $slotConfirmationService
     ;
     }
     public function __invoke(Command $command): void
     {
     $appointment = Appointment
     ::create(
     AppointmentId
     ::generate(),
     Pet::create(
     $command->getPetName
     (),
     $command->getOwnerName
     (),
     $command->getContactNumber
     ()
     ),
     $command->getAppointmentTime
     (),
     $command->getAppointmentLengthInMinutes
     ()
     );
     try {
     $this
     ->slotConfirmationService
     ->confirmSlot
     ($appointment);
     } catch (CouldNotConfirmSlotException $exception) {
     throw new \RuntimeException
     ("The slot could not be booked"
     );
     }
     }
     }
     public
     src
     AcmeVet
     config
     Infrastructure
     Scheduling
     Application
     Domain
     AppointmentBookingCommand.php
     Command
     Booking
     AppointmentBookingHandler.php
     migrations
     composer.json
     App
     templates
     tests
     Bounded Context
     

     View Slide

110. Services:
     # ...
     # Tell Symfony to auto-wire everything that it finds
     # within the AcmeVet namespace
     AcmeVet\
     :
     resource: '../src/AcmeVet/'
     AcmeVet\Scheduling\Application\Command\Booking\AppointmentBookingHandler
     :
     tags: [messenger.message_handler
     ]
     public
     src
     AcmeVet
     config
     Infrastructure
     Scheduling
     Application
     Domain
     AppointmentBookingCommand.php
     Command
     Booking
     AppointmentBookingHandler.php
     services.yaml
     migrations
     composer.json
     App
     templates
     tests
     Bounded Context
     

     View Slide

111. The UI
     

     View Slide

112. class AppointmentController extends AbstractController
     {
     private MessageBusInterface $messageBus
     ;
     public function __construct
     (MessageBusInterface $messageBus
     )
     {
     $this
     ->messageBus = $messageBus
     ;
     }
     /**
     * @Route("/appointments", name="appointments");
     */
     public function list(Request $request): Response
     {
     $form = $this->createForm
     (AppointmentType
     ::class);
     $form
     ->handleRequest
     ($request);
     if ($form->isSubmitted
     () && $form->isValid()) {
     $command = new AppointmentBookingCommand
     (
     $form
     ->get('appointmentTime'
     )->getData(),
     $form
     ->get('petName')->getData(),
     $form
     ->get('ownerName'
     )->getData(),
     $form
     ->get('contactNumber'
     )->getData(),
     true === $form->get('appointmentLength'
     )->getData() ? 30 : 15
     );
     $this
     ->messageBus
     ->dispatch($command);
     }
     return $this->render('appointment/list.html.twig'
     , [
     'form' => $form->createView
     ()
     ]);
     }
     }
     public
     src
     AcmeVet
     config
     App
     templates
     tests
     composer.json
     Kernel.php
     AppointmentController.php
     migrations
     Controller
     Entity
     Form
     Repository
     

     View Slide

113. class AppointmentController extends AbstractController
     {
     private MessageBusInterface $messageBus
     ;
     public function __construct
     (MessageBusInterface $messageBus
     )
     {
     $this
     ->messageBus = $messageBus
     ;
     }
     /**
     * @Route("/appointments", name="appointments");
     */
     public function list(Request $request): Response
     {
     $form = $this->createForm
     (AppointmentType
     ::class);
     $form
     ->handleRequest
     ($request);
     if ($form->isSubmitted
     () && $form->isValid()) {
     $command = new AppointmentBookingCommand
     (
     $form
     ->get('appointmentTime'
     )->getData(),
     $form
     ->get('petName')->getData(),
     $form
     ->get('ownerName'
     )->getData(),
     $form
     ->get('contactNumber'
     )->getData(),
     true === $form->get('appointmentLength'
     )->getData() ? 30 : 15
     );
     $this
     ->messageBus
     ->dispatch($command);
     }
     return $this->render('appointment/list.html.twig'
     , [
     'form' => $form->createView
     ()
     ]);
     }
     }
     public
     src
     AcmeVet
     config
     App
     composer.json
     AppointmentController.php
     migrations
     Controller
     Entity
     Form
     Repository
     templates
     tests
     Kernel.php
     

     View Slide

114. class AppointmentController extends AbstractController
     {
     private MessageBusInterface $messageBus
     ;
     public function __construct
     (MessageBusInterface $messageBus
     )
     {
     $this
     ->messageBus = $messageBus
     ;
     }
     /**
     * @Route("/appointments", name="appointments");
     */
     public function list(Request $request): Response
     {
     $form = $this->createForm
     (AppointmentType
     ::class);
     $form
     ->handleRequest
     ($request);
     if ($form->isSubmitted
     () && $form->isValid()) {
     $command = new AppointmentBookingCommand
     (
     $form
     ->get('appointmentTime'
     )->getData(),
     $form
     ->get('petName')->getData(),
     $form
     ->get('ownerName'
     )->getData(),
     $form
     ->get('contactNumber'
     )->getData(),
     true === $form->get('appointmentLength'
     )->getData() ? 30 : 15
     );
     $this
     ->messageBus
     ->dispatch($command);
     }
     return $this->render('appointment/list.html.twig'
     , [
     'form' => $form->createView
     ()
     ]);
     }
     }
     public
     src
     AcmeVet
     config
     App
     composer.json
     Kernel.php
     AppointmentController.php
     migrations
     Controller
     Entity
     Form
     Repository
     templates
     tests
     

     View Slide

115. class AppointmentController extends AbstractController
     {
     private MessageBusInterface $messageBus
     ;
     public function __construct
     (MessageBusInterface $messageBus
     )
     {
     $this
     ->messageBus = $messageBus
     ;
     }
     /**
     * @Route("/appointments", name="appointments");
     */
     public function list(Request $request): Response
     {
     $form = $this->createForm
     (AppointmentType
     ::class);
     $form
     ->handleRequest
     ($request);
     if ($form->isSubmitted
     () && $form->isValid()) {
     $command = new AppointmentBookingCommand
     (
     $form
     ->get('appointmentTime'
     )->getData(),
     $form
     ->get('petName')->getData(),
     $form
     ->get('ownerName'
     )->getData(),
     $form
     ->get('contactNumber'
     )->getData(),
     true === $form->get('appointmentLength'
     )->getData() ? 30 : 15
     );
     $this
     ->messageBus
     ->dispatch($command);
     }
     return $this->render('appointment/list.html.twig'
     , [
     'form' => $form->createView
     ()
     ]);
     }
     }
     public
     src
     AcmeVet
     config
     App
     composer.json
     Kernel.php
     AppointmentController.php
     migrations
     Controller
     Entity
     Form
     Repository
     templates
     tests
     

     View Slide

116. namespace App\Form\Type;
     class AppointmentType extends AbstractType
     {
     public function buildForm(FormBuilderInterface $builder, array $options)
     {
     $builder
     ->add('appointmentTime'
     , DateTimeType
     ::class, [
     'input' => 'datetime_immutable'
     ,
     'widget' => 'single_text'
     ,
     'attr' => [
     'step' => 900,
     'min' => (new \DateTimeImmutable
     ())->format('Y-m-d')
     ]
     ])
     ->add('petName', TextType::class)
     ->add('ownerName'
     , TextType::class)
     ->add('contactNumber'
     , TextType::class)
     ->add('appointmentLength'
     , ChoiceType
     ::class, [
     'choices' => [
     'single' => false,
     'double' => true
     ]
     ])
     ->add('submit', SubmitType
     ::class);
     }
     }
     public
     src
     AcmeVet
     config
     App
     composer.json
     Kernel.php
     AppointmentController.php
     migrations
     Controller
     Entity
     Form
     Repository
     Type
     templates
     tests
     

     View Slide

117. View Slide

118. View Slide

119. namespace AcmeVet\Scheduling
     \Application
     \Query;
     use AcmeVet\Appointment
     \Domain\Appointment
     ;
     use AcmeVet\Appointment
     \Domain\AppointmentRepository
     ;
     class AppointmentQuery
     {
     private AppointmentRepository $repository
     ;
     public function __construct
     (AppointmentRepository $repository
     )
     {
     $this
     ->repository = $repository
     ;
     }
     public function fetchAll(): array
     {
     $results = $this->repository
     ->getAll();
     return \array_map(function (Appointment $item) {
     return new AppointmentDTO
     (
     $item->getStartTime
     (),
     15 === $item->getLengthInMinutes
     () ? false : true,
     $item->getPet()->getName(),
     $item->getPet()->getOwnerName
     (),
     $item->getPet()->getContactNumber
     ()
     );
     }, $results);
     }
     }
     public
     src
     AcmeVet
     config
     Infrastructure
     Scheduling
     Application
     Domain
     App
     templates
     tests
     composer.json
     Command
     Query
     AppointmentQuery.php
     migrations
     Bounded Context
     

     View Slide

120. namespace AcmeVet\Scheduling
     \Application
     \Query;
     use AcmeVet\Appointment
     \Domain\Appointment
     ;
     use AcmeVet\Appointment
     \Domain\AppointmentRepository
     ;
     class AppointmentQuery
     {
     private AppointmentRepository $repository
     ;
     public function __construct
     (AppointmentRepository $repository
     )
     {
     $this
     ->repository = $repository
     ;
     }
     public function fetchAll(): array
     {
     $results = $this->repository
     ->getAll();
     return \array_map(function (Appointment $item) {
     return new AppointmentDTO
     (
     $item->getStartTime
     (),
     15 === $item->getLengthInMinutes
     () ? false : true,
     $item->getPet()->getName(),
     $item->getPet()->getOwnerName
     (),
     $item->getPet()->getContactNumber
     ()
     );
     }, $results);
     }
     }
     public
     src
     AcmeVet
     config
     Infrastructure
     Scheduling
     Application
     Domain
     App
     composer.json
     Command
     Query
     AppointmentQuery.php
     migrations
     templates
     tests
     Bounded Context
     

     View Slide

121. namespace AcmeVet\Scheduling
     \Application
     \Query;
     use AcmeVet\Appointment
     \Domain\Appointment
     ;
     use AcmeVet\Appointment
     \Domain\AppointmentRepository
     ;
     class AppointmentQuery
     {
     private AppointmentRepository $repository
     ;
     public function __construct
     (AppointmentRepository $repository
     )
     {
     $this
     ->repository = $repository
     ;
     }
     public function fetchAll(): array
     {
     $results = $this->repository
     ->getAll();
     return \array_map(function (Appointment $item) {
     return new AppointmentDTO
     (
     $item->getStartTime
     (),
     15 === $item->getLengthInMinutes
     () ? false : true,
     $item->getPet()->getName(),
     $item->getPet()->getOwnerName
     (),
     $item->getPet()->getContactNumber
     ()
     );
     }, $results);
     }
     }
     public
     src
     AcmeVet
     config
     Infrastructure
     Scheduling
     Application
     Domain
     App
     composer.json
     Command
     Query
     AppointmentQuery.php
     migrations
     templates
     tests
     Bounded Context
     

     View Slide

122. namespace AcmeVet\Scheduling
     \Application
     \Query;
     use AcmeVet\Appointment
     \Domain\Appointment
     ;
     use AcmeVet\Appointment
     \Domain\AppointmentRepository
     ;
     class AppointmentQuery
     {
     private AppointmentRepository $repository
     ;
     public function __construct
     (AppointmentRepository $repository
     )
     {
     $this
     ->repository = $repository
     ;
     }
     public function fetchAll(): array
     {
     $results = $this->repository
     ->getAll();
     return \array_map(function (Appointment $item) {
     return new AppointmentDTO
     (
     $item->getStartTime
     (),
     15 === $item->getLengthInMinutes
     () ? false : true,
     $item->getPet()->getName(),
     $item->getPet()->getOwnerName
     (),
     $item->getPet()->getContactNumber
     ()
     );
     }, $results);
     }
     }
     public
     src
     AcmeVet
     config
     Infrastructure
     Scheduling
     Application
     Domain
     App
     composer.json
     Command
     Query
     AppointmentQuery.php
     migrations
     templates
     tests
     Bounded Context
     

     View Slide

123. namespace AcmeVet\Scheduling
     \Application
     \Query;
     use AcmeVet\Appointment
     \Domain\Appointment
     ;
     use AcmeVet\Appointment
     \Domain\AppointmentRepository
     ;
     class AppointmentQuery
     {
     private AppointmentRepository $repository
     ;
     public function __construct
     (AppointmentRepository $repository
     )
     {
     $this
     ->repository = $repository
     ;
     }
     public function fetchAll(): array
     {
     $results = $this->repository
     ->getAll();
     return \array_map(function (Appointment $item) {
     return new AppointmentDTO
     (
     $item->getStartTime
     (),
     15 === $item->getLengthInMinutes
     () ? false : true,
     $item->getPet()->getName(),
     $item->getPet()->getOwnerName
     (),
     $item->getPet()->getContactNumber
     ()
     );
     }, $results);
     }
     }
     public
     src
     AcmeVet
     config
     Infrastructure
     Scheduling
     Application
     Domain
     App
     composer.json
     Command
     Query
     AppointmentQuery.php
     migrations
     templates
     tests
     Bounded Context
     

     View Slide

124. class AppointmentDTO
     {
     private \DateTimeImmutable $startTime
     ;
     private bool $isDoubleAppointment
     ;
     private string $petName;
     private string $ownerName
     ;
     private string $contactNumber
     ;
     public function __construct
     (
     \DateTimeImmutable $startTime
     ,
     bool $isDoubleAppointment
     ,
     string $petName,
     string $ownerName
     ,
     string $contactNumber
     )
     {
     $this
     ->startTime = $startTime
     ;
     $this
     ->isDoubleAppointment = $isDoubleAppointment
     ;
     $this
     ->petName = $petName;
     $this
     ->ownerName = $ownerName
     ;
     $this
     ->contactNumber = $contactNumber
     ;
     }
     public function getStartTime
     (): \DateTimeImmutable
     {
     return $this->startTime;
     }
     public function getPetName
     (): string
     {
     return $this->petName;
     }
     public function getOwnerName
     (): string
     {
     return $this->ownerName;
     }
     public function getContactNumber
     (): string
     {
     return $this->contactNumber
     ;
     }
     public function isDoubleAppointment
     (): bool
     {
     return $this->isDoubleAppointment
     ;
     }
     }
     public
     src
     AcmeVet
     config
     Infrastructure
     Scheduling
     Application
     Domain
     App
     composer.json
     Command
     Query
     AppointmentQuery.php
     migrations
     AppointmentDTO.php
     templates
     tests
     Bounded Context
     

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125. class AppointmentController extends AbstractController
     {
     /**
     * @Route("/appointments", name="appointments");
     */
     public function list(Request $request, AppointmentQuery $appointmentList
     ): Response
     {
     $form = $this->createForm
     (AppointmentType
     ::class);
     $form
     ->handleRequest
     ($request);
     if ($form->isSubmitted
     () && $form->isValid()) {
     $command = new AppointmentBookingCommand
     (
     $form
     ->get('appointmentTime'
     )->getData(),
     $form
     ->get('petName')->getData(),
     $form
     ->get('ownerName'
     )->getData(),
     $form
     ->get('contactNumber'
     )->getData(),
     true === $form->get('appointmentLength'
     )->getData() ? 30 : 15
     );
     $this
     ->messageBus
     ->dispatch($command);
     }
     $appointments = $appointmentList
     ->fetchAll();
     return $this->render('appointment/list.html.twig'
     , [
     'appointments' => $appointments,
     'form' => $form->createView
     ()
     ]);
     }
     }
     public
     src
     AcmeVet
     config
     App
     composer.json
     Kernel.php
     AppointmentController.php
     migrations
     Controller
     Entity
     Form
     Repository
     templates
     tests
     

     View Slide

126. class AppointmentController extends AbstractController
     {
     /**
     * @Route("/appointments", name="appointments");
     */
     public function list(Request $request, AppointmentQuery $appointmentList
     ): Response
     {
     $form = $this->createForm
     (AppointmentType
     ::class);
     $form
     ->handleRequest
     ($request);
     if ($form->isSubmitted
     () && $form->isValid()) {
     $command = new AppointmentBookingCommand
     (
     $form
     ->get('appointmentTime'
     )->getData(),
     $form
     ->get('petName')->getData(),
     $form
     ->get('ownerName'
     )->getData(),
     $form
     ->get('contactNumber'
     )->getData(),
     true === $form->get('appointmentLength'
     )->getData() ? 30 : 15
     );
     $this
     ->messageBus
     ->dispatch($command);
     }
     $appointments = $appointmentList
     ->fetchAll();
     return $this->render('appointment/list.html.twig'
     , [
     'appointments' => $appointments,
     'form' => $form->createView
     ()
     ]);
     }
     }
     public
     src
     AcmeVet
     config
     App
     composer.json
     Kernel.php
     AppointmentController.php
     migrations
     Controller
     Entity
     Form
     Repository
     templates
     tests
     

     View Slide

127. class AppointmentController extends AbstractController
     {
     /**
     * @Route("/appointments", name="appointments");
     */
     public function list(Request $request, AppointmentQuery $appointmentList
     ): Response
     {
     $form = $this->createForm
     (AppointmentType
     ::class);
     $form
     ->handleRequest
     ($request);
     if ($form->isSubmitted
     () && $form->isValid()) {
     $command = new AppointmentBookingCommand
     (
     $form
     ->get('appointmentTime'
     )->getData(),
     $form
     ->get('petName')->getData(),
     $form
     ->get('ownerName'
     )->getData(),
     $form
     ->get('contactNumber'
     )->getData(),
     true === $form->get('appointmentLength'
     )->getData() ? 30 : 15
     );
     $this
     ->messageBus
     ->dispatch($command);
     }
     $appointments = $appointmentList
     ->fetchAll();
     return $this->render('appointment/list.html.twig'
     , [
     'appointments' => $appointments,
     'form' => $form->createView
     ()
     ]);
     }
     }
     public
     src
     AcmeVet
     config
     App
     composer.json
     Kernel.php
     AppointmentController.php
     migrations
     Controller
     Entity
     Form
     Repository
     templates
     tests
     

     View Slide

128. View Slide

129. View Slide

130. The second bounded context
     

     View Slide

131. public
     src
     AcmeVet
     config
     Infrastructure
     Consultation
     Application
     Domain
     App
     composer.json
     migrations
     Scheduling
     templates
     tests
     Bounded Context
     Bounded Context
     

     View Slide

132. namespace AcmeVet\Consultation
     \Domain\Pet;
     class Pet
     {
     private PetId $petId;
     private Animal $animal;
     private string $petName;
     private \DateTimeImmutable $dateOfBirth
     ;
     private array $diagnoses = [];
     private array $consultations = [];
     private function __construct
     (
     PetId $petId,
     Animal $animal,
     string $petName,
     \DateTimeImmutable $dateOfBirth
     ) {
     $this
     ->petId = $petId;
     $this
     ->animal = $animal;
     $this
     ->petName = $petName;
     $this
     ->dateOfBirth = $dateOfBirth
     ;
     }
     public static function create(
     PetId $petId,
     Animal $animal,
     string $petName,
     \DateTimeImmutable $dateOfBirth
     ): self {
     return new self
     ($petId, $animal, $petName, $dateOfBirth
     );
     }
     public function recordConsultation
     (Consultation $consultation
     ): void
     {
     $this
     ->consultations
     [] = $consultation
     ;
     }
     public function getBreed(): string
     {
     return (new \ReflectionClass
     ($this->animal))->getShortName
     () . '/' . $this->animal->getBreedName
     ();
     }
     public function addDiagnosis
     (Diagnosis $diagnosis
     ): void
     {
     $this
     ->diagnoses[] = $diagnosis
     ;
     }
     public
     src
     AcmeVet
     config
     Infrastructure
     Consultation
     Application
     Domain
     App
     composer.json
     migrations
     Scheduling
     Pet
     Pet.php
     templates
     tests
     Bounded Context
     Aggregate
     Aggregate
     Root
     Bounded Context
     

     View Slide

133. Application data
     

     View Slide

134. namespace App\Entity;
     use Doctrine\ORM\Mapping as ORM;
     use Symfony\Component\Security\Core\User\UserInterface;
     /**
     * @ORM\Table(name="app_users")
     * @ORM\Entity(repositoryClass="App\Repository\UserRepository")
     */
     class User implements UserInterface, \Serializable
     {
     /**
     * @ORM\Column(type="integer")
     * @ORM\Id
     * @ORM\GeneratedValue(strategy="AUTO")
     */
     private $id;
     /**
     * @ORM\Column(type="string", length=25, unique=true)
     */
     private $username;
     /**
     * @ORM\Column(type="string", length=64)
     */
     private $password;
     /**
     * @ORM\Column(type="string", length=254, unique=true)
     */
     private $email;
     /**
     * @ORM\Column(name="is_active", type="boolean")
     */
     private $isActive;
     public function __construct()
     {
     $this->isActive = true;
     // may not be needed, see section on salt below
     // $this->salt = md5(uniqid('', true));
     }
     public function getUsername()
     public
     src
     AcmeVet
     config
     App
     composer.json
     Kernel.php
     User.php
     migrations
     Controller
     Entity
     Form
     Repository
     templates
     tests
     

     View Slide

135. Do it yourself ● Think about the words you use in the
     business
     ● Identify Bounded Contexts
     ● Think about who the domain experts are for
     each Bounded Context
     ● Start talking about business processes and
     invariants in each Bounded Context
     ● Identify the aggregates
     ● Build the software
     

     View Slide

136. Do it yourself ● Think about the words you use in the
     business
     ● Identify Bounded Contexts
     ● Think about who the domain experts are for
     each Bounded Context
     ● Start talking about business processes and
     invariants in each Bounded Context
     ● Identify the aggregates
     ● Build the software
     https://github.com/nealio82/
     absolute-beginners-guide-to-ddd-with-symfony
     

     View Slide

137. Do it yourself
     https://github.com/nealio82/
     absolute-beginners-guide-to-ddd-with-symfony
     ● Think about the words you use in the
     business
     ● Identify Bounded Contexts
     ● Think about who the domain experts are for
     each Bounded Context
     ● Start talking about business processes and
     invariants in each Bounded Context
     ● Identify the aggregates
     ● Build the software
     @nealio82
     

     View Slide

138. Do it yourself
     https://github.com/nealio82/
     absolute-beginners-guide-to-ddd-with-symfony
     ● Think about the words you use in the
     business
     ● Identify Bounded Contexts
     ● Think about who the domain experts are for
     each Bounded Context
     ● Start talking about business processes and
     invariants in each Bounded Context
     ● Identify the aggregates
     ● Build the software
     @nealio82
     Thanks to @edd_mann, @lucas_courot, and @jim_jqim
     

     View Slide

139. Do it yourself
     https://github.com/nealio82/
     absolute-beginners-guide-to-ddd-with-symfony
     ● Think about the words you use in the
     business
     ● Identify Bounded Contexts
     ● Think about who the domain experts are for
     each Bounded Context
     ● Start talking about business processes and
     invariants in each Bounded Context
     ● Identify the aggregates
     ● Build the software
     @nealio82
     Thanks to @edd_mann, @lucas_courot, and @jim_jqim, and you!
     

     View Slide