PHP设计模式范例 — DesignPatternsPHP（1）创建型设计模式

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【搬运于 GitHub 开源项目 DesignPatternsPHP】
项目地址：戳我

1、创建型设计模式
在软件工程中，创建型设计模式承担着对象创建的职责，尝试创建适合程序上下文的对象，对象创建设计模式的产生是由于软件工程设计的问题，具体说是向设计中增加复杂度，创建型设计模式解决了程序设计中对象创建的问题。
1.1 抽象工厂
1.1.1 目的
创建一系列相关或依赖的对象，而不指定它们的具体类。通常创建的类都实现相同的接口。抽象工厂的客户端并不关心这些对象是如何创建的，它只知道它们是如何组合在一起的。
1.1.2 UML 图

1.1.3 代码
你可以在 GitHub 上查看代码
Parser.php
<?php
namespace DesignPatterns\Creational\AbstractFactory;

interface Parser
{
public function parse(string $input): array;
}
CsvParser.php
<?php

namespace DesignPatterns\Creational\AbstractFactory;

class CsvParser implements Parser
{
const OPTION_CONTAINS_HEADER = true;
const OPTION_CONTAINS_NO_HEADER = false;

/**
* @var bool
*/
private $skipHeaderLine;

public function __construct(bool $skipHeaderLine)
{
$this->skipHeaderLine = $skipHeaderLine;
}

public function parse(string $input): array
{
$headerWasParsed = false;
$parsedLines = [];

foreach (explode(PHP_EOL, $input) as $line) {
if (!$headerWasParsed && $this->skipHeaderLine === self::OPTION_CONTAINS_HEADER) {
$headerWasParsed = true;
continue;
}

$parsedLines[] = str_getcsv($line);
}

return $parsedLines;
}
}
JsonParser.php
<?php

namespace DesignPatterns\Creational\AbstractFactory;

class JsonParser implements Parser
{
public function parse(string $input): array
{
return json_decode($input, true);
}
}
ParserFactory.php
<?php

namespace DesignPatterns\Creational\AbstractFactory;

class ParserFactory
{
public function createCsvParser(bool $skipHeaderLine): CsvParser
{
return new CsvParser($skipHeaderLine);
}

public function createJsonParser(): JsonParser
{
return new JsonParser();
}
}
1.2 生成器模式
1.2.1 目的
生成器的目的是将复杂对象的创建过程（流程）进行抽象，生成器表现为接口的形式。
在特定的情况下，比如如果生成器对将要创建的对象有足够多的了解，那么代表生成器的接口 interface 可以是一个抽象类(也就是说可以有一定的具体实现，就像众所周知的适配器模式)。
如果对象有复杂的继承树，理论上创建对象的生成器也同样具有复杂的继承树。
提示：生成器通常具有流畅的接口，推荐阅读关于 PHPUnit 的 mock 生成器获取更好的理解。
1.2.2 例子
PHPUnit: Mock 生成器
1.2.3 UML 图

1.2.4 代码
你可以在 GitHub 上找到这些代码
Director.php
<?php

namespace DesignPatterns\Creational\Builder;

use DesignPatterns\Creational\Builder\Parts\Vehicle;

/**
* Director is part of the builder pattern. It knows the interface of the builder
* and builds a complex object with the help of the builder
*
* You can also inject many builders instead of one to build more complex objects
*/
class Director
{
public function build(BuilderInterface $builder): Vehicle
{
$builder->createVehicle();
$builder->addDoors();
$builder->addEngine();
$builder->addWheel();

return $builder->getVehicle();
}
}
BuilderInterface.php
<?php

namespace DesignPatterns\Creational\Builder;

use DesignPatterns\Creational\Builder\Parts\Vehicle;

interface BuilderInterface
{
public function createVehicle();

public function addWheel();

public function addEngine();

public function addDoors();

public function getVehicle(): Vehicle;
}
TruckBuilder.php
<?php

namespace DesignPatterns\Creational\Builder;

use DesignPatterns\Creational\Builder\Parts\Vehicle;

class TruckBuilder implements BuilderInterface
{
/**
* @var Parts\Truck
*/
private $truck;

public function addDoors()
{
$this->truck->setPart(‘rightDoor’, new Parts\Door());
$this->truck->setPart(‘leftDoor’, new Parts\Door());
}

public function addEngine()
{
$this->truck->setPart(‘truckEngine’, new Parts\Engine());
}

public function addWheel()
{
$this->truck->setPart(‘wheel1’, new Parts\Wheel());
$this->truck->setPart(‘wheel2’, new Parts\Wheel());
$this->truck->setPart(‘wheel3’, new Parts\Wheel());
$this->truck->setPart(‘wheel4’, new Parts\Wheel());
$this->truck->setPart(‘wheel5’, new Parts\Wheel());
$this->truck->setPart(‘wheel6’, new Parts\Wheel());
}

public function createVehicle()
{
$this->truck = new Parts\Truck();
}

public function getVehicle(): Vehicle
{
return $this->truck;
}
}
CarBuilder.php
<?php

namespace DesignPatterns\Creational\Builder;

use DesignPatterns\Creational\Builder\Parts\Vehicle;

class CarBuilder implements BuilderInterface
{
/**
* @var Parts\Car
*/
private $car;

public function addDoors()
{
$this->car->setPart(‘rightDoor’, new Parts\Door());
$this->car->setPart(‘leftDoor’, new Parts\Door());
$this->car->setPart(‘trunkLid’, new Parts\Door());
}

public function addEngine()
{
$this->car->setPart(‘engine’, new Parts\Engine());
}

public function addWheel()
{
$this->car->setPart(‘wheelLF’, new Parts\Wheel());
$this->car->setPart(‘wheelRF’, new Parts\Wheel());
$this->car->setPart(‘wheelLR’, new Parts\Wheel());
$this->car->setPart(‘wheelRR’, new Parts\Wheel());
}

public function createVehicle()
{
$this->car = new Parts\Car();
}

public function getVehicle(): Vehicle
{
return $this->car;
}
}
Parts/Vehicle.php
<?php