简单工厂模式（Simple Factory）

目的

简单工厂模式是一个精简版的工厂模式。

它与静态工厂模式最大的区别是它不是『静态』的。因为非静态，所以你可以拥有多个不同参数的工厂，你可以为其创建子类。甚至可以模拟（Mock）他，这对编写可测试的代码来讲至关重要。 这也是它比静态工厂模式受欢迎的原因！

UML 图

tsAa4MVih0.png

代码

你可以在 GitHub 查看这段代码。

SimpleFactory.php

  2. <?php
  4. namespace DesignPatterns\Creational\SimpleFactory;
  6. class SimpleFactory
  7. {
  8.     public function createBicycle(): Bicycle
  9.     {
  10.         return new Bicycle();
  11.     }
  12. }

Bicycle.php

  2. <?php
  4. namespace DesignPatterns\Creational\SimpleFactory;
  6. class Bicycle
  7. {
  8.     public function driveTo(string $destination)
  9.     {
  10.         return $destination;
  11.     }
  12. }

用法

  2.  $factory = new SimpleFactory();
  3.  $bicycle = $factory->createBicycle();
  4.  $bicycle->driveTo('Paris');

测试

Tests/SimpleFactoryTest.php

  2. <?php
  4. namespace DesignPatterns\Creational\SimpleFactory\Tests;
  6. use DesignPatterns\Creational\SimpleFactory\Bicycle;
  7. use DesignPatterns\Creational\SimpleFactory\SimpleFactory;
  8. use PHPUnit\Framework\TestCase;
  10. class SimpleFactoryTest extends TestCase
  11. {
  12.     public function testCanCreateBicycle()
  13.     {
  14.         $bicycle = (new SimpleFactory())->createBicycle();
  15.         $this->assertInstanceOf(Bicycle::class, $bicycle);
  16.     }
  17. }