这种模式提供了一种简单的解耦多组件之间的协同工作方式。如果你有一个“智能中心”,比如控制器(但不是 MVC 的意义上),它是观察者的一个很好的替代品。
所有组件(称为同事)仅与 Mediator 接口耦合,这是一件好事,因为在 OOP 中,一个好朋友胜过多个。这是这种模式的关键特征。
Mediator.php
<?php
declare(strict_types=1);
namespace DesignPatterns\Behavioral\Mediator;
interface Mediator
{
public function getUser(string $username): string;
}
Colleague.php
<?php
declare(strict_types=1);
namespace DesignPatterns\Behavioral\Mediator;
abstract class Colleague
{
protected Mediator $mediator;
public function setMediator(Mediator $mediator)
{
$this->mediator = $mediator;
}
}
Ui.php
<?php
declare(strict_types=1);
namespace DesignPatterns\Behavioral\Mediator;
class Ui extends Colleague
{
public function outputUserInfo(string $username)
{
echo $this->mediator->getUser($username);
}
}
UserRepository.php
<?php
declare(strict_types=1);
namespace DesignPatterns\Behavioral\Mediator;
class UserRepository extends Colleague
{
public function getUserName(string $user): string
{
return 'User: ' . $user;
}
}
UserRepositoryUiMediator.php
<?php
declare(strict_types=1);
namespace DesignPatterns\Behavioral\Mediator;
class UserRepositoryUiMediator implements Mediator
{
public function __construct(private UserRepository $userRepository, private Ui $ui)
{
$this->userRepository->setMediator($this);
$this->ui->setMediator($this);
}
public function printInfoAbout(string $user)
{
$this->ui->outputUserInfo($user);
}
public function getUser(string $username): string
{
return $this->userRepository->getUserName($username);
}
}
Tests/MediatorTest.php
<?php
declare(strict_types=1);
namespace DesignPatterns\Tests\Mediator\Tests;
use DesignPatterns\Behavioral\Mediator\Ui;
use DesignPatterns\Behavioral\Mediator\UserRepository;
use DesignPatterns\Behavioral\Mediator\UserRepositoryUiMediator;
use PHPUnit\Framework\TestCase;
class MediatorTest extends TestCase
{
public function testOutputHelloWorld()
{
$mediator = new UserRepositoryUiMediator(new UserRepository(), new Ui());
$this->expectOutputString('User: Dominik');
$mediator->printInfoAbout('Dominik');
}
}