原型模式

目的

为了避免以标准方式创建对象(如:new Foo())带来的成本,原型模式是通过创建对象的原型并克隆它的方式来创建对象。

使用场景

  • 一次性创建大量的数据(例如:在数据库中,通过 ORM 一次性创建 1,000,000 条数据)

UML 类图

原型模式类图

代码

BookPrototype.php

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<?php declare(strict_types = 1);

namespace DesignPatterns\Creational\Prototype;

abstract class BookPrototype
{
protected string $title;
protected string $category;

abstract public function __clone();

public function getTitle(): string
{
return $this->title;
}

public function setTitle(string $title)
{
$this->title = $title;
}
}

BarBookPrototype.php

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<?php declare(strict_types = 1);

namespace DesignPatterns\Creational\Prototype;

class BarBookPrototype extends BookPrototype
{
protected string $category = 'Bar';

public function __clone()
{
}
}

FooBookPrototype.php

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<?php declare(strict_types = 1);

namespace DesignPatterns\Creational\Prototype;

class FooBookPrototype extends BookPrototype
{
protected string $category = 'Foo';

public function __clone()
{
}
}

测试

Tests/PrototypeTest.php

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<?php declare(strict_types = 1);

namespace DesignPatterns\Creational\Prototype\Tests;

use DesignPatterns\Creational\Prototype\BarBookPrototype;
use DesignPatterns\Creational\Prototype\FooBookPrototype;
use PHPUnit\Framework\TestCase;

class PrototypeTest extends TestCase
{
public function testCanGetFooBook()
{
$fooPrototype = new FooBookPrototype();
$barPrototype = new BarBookPrototype();

for ($i = 0; $i < 10; $i++) {
$book = clone $fooPrototype;
$book->setTitle('Foo Book No ' . $i);
$this->assertInstanceOf(FooBookPrototype::class, $book);
}

for ($i = 0; $i < 5; $i++) {
$book = clone $barPrototype;
$book->setTitle('Bar Book No ' . $i);
$this->assertInstanceOf(BarBookPrototype::class, $book);
}
}
}