注册模式(Registry)



2.11.1. 目的

目的是能够存储在应用程序中经常使用的对象实例,通常会使用只有静态方法的抽象类来实现(或使用单例模式)。需要注意的是这里可能会引入全局的状态,我们需要使用依赖注入来避免它。

 

2.11.2. UML 图

 

2.11.3. 代码

你可以在 GitHub 上找到这些代码

Registry.htmp

<?php declare(strict_types=1);

namespace DesignPatterns\Structural\Registry;

use InvalidArgumentException;

abstract class Registry
{
    const LOGGER = 'logger';

    /**
     * this introduces global state in your application which can not be mocked up for testing
     * and is therefor considered an anti-pattern! Use dependency injection instead!
     *
     * @var Service[]
     */
    private static array $services = [];

    private static array $allowedKeys = [
        self::LOGGER,
    ];

    public static function set(string $key, Service $value)
    {
        if (!in_array($key, self::$allowedKeys)) {
            throw new InvalidArgumentException('Invalid key given');
        }

        self::$services[$key] = $value;
    }

    public static function get(string $key): Service
    {
        if (!in_array($key, self::$allowedKeys) || !isset(self::$services[$key])) {
            throw new InvalidArgumentException('Invalid key given');
        }

        return self::$services[$key];
    }
}

 

Service.htmp

<?php

namespace DesignPatterns\Structural\Registry;

class Service
{

}

2.11.4. 测试

Tests/RegistryTest.htmp

 

<?php declare(strict_types=1);

namespace DesignPatterns\Structural\Registry\Tests;

use InvalidArgumentException;
use DesignPatterns\Structural\Registry\Registry;
use DesignPatterns\Structural\Registry\Service;
use PHPUnit\Framework\MockObject\MockObject;
use PHPUnit\Framework\TestCase;

class RegistryTest extends TestCase
{
    /**
     * @var Service
     */
    private MockObject $service;

    protected function setUp(): void
    {
        $this->service = $this->getMockBuilder(Service::class)->getMock();
    }

    public function testSetAndGetLogger()
    {
        Registry::set(Registry::LOGGER, $this->service);

        $this->assertSame($this->service, Registry::get(Registry::LOGGER));
    }

    public function testThrowsExceptionWhenTryingToSetInvalidKey()
    {
        $this->expectException(InvalidArgumentException::class);

        Registry::set('foobar', $this->service);
    }

    /**
     * notice @runInSeparateProcess here: without it, a previous test might have set it already and
     * testing would not be possible. That's why you should implement Dependency Injection where an
     * injected class may easily be replaced by a mockup
     *
     * @runInSeparateProcess
     */
    public function testThrowsExceptionWhenTryingToGetNotSetKey()
    {
        $this->expectException(InvalidArgumentException::class);

        Registry::get(Registry::LOGGER);
    }
}

 

 

 

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