目的
建造者是创建一个复杂对象的一部分接口。
有时候，如果建造者对他所创建的东西拥有较好的知识储备，这个接口就可能成为一个有默认方法的抽象类（又称为适配器）。
如果对象有复杂的继承树，那么对于建造者来说，有一个复杂继承树也是符合逻辑的。
注意：建造者通常有一个「流式接口」，例如 PHPUnit 模拟生成器。
例子
- PHPUnit: 模拟生成器
UML Diagram
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代码
- Director.php
<?php
namespace DesignPatterns\Creational\Builder;
use DesignPatterns\Creational\Builder\Parts\Vehicle;
/**
* Director 类是建造者模式的一部分。 它可以实现建造者模式的接口
* 并在构建器的帮助下构建一个复杂的对象
*
* 您也可以注入许多构建器而不是构建更复杂的对象
*/
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
namespace DesignPatterns\Creational\Builder\Parts;
abstract class Vehicle
{
/**
* @var object[]
*/
private $data = [];
/**
* @param string $key
* @param object $value
*/
public function setPart($key, $value)
{
$this->data[$key] = $value;
}
}
- Parts/Truck.php
<?php
namespace DesignPatterns\Creational\Builder\Parts;
class Truck extends Vehicle
{
}
- Parts/Car.php
<?php
namespace DesignPatterns\Creational\Builder\Parts;
class Car extends Vehicle
{
}
- Parts/Engine.php
<?php
namespace DesignPatterns\Creational\Builder\Parts;
class Engine
{
}
- Parts/Wheel.php
<?php
namespace DesignPatterns\Creational\Builder\Parts;
class Wheel
{
}
- Parts/Door.php
<?php
namespace DesignPatterns\Creational\Builder\Parts;
class Door
{
}
测试
- Tests/DirectorTest.php
<?php
namespace DesignPatterns\Creational\Builder\Tests;
use DesignPatterns\Creational\Builder\Parts\Car;
use DesignPatterns\Creational\Builder\Parts\Truck;
use DesignPatterns\Creational\Builder\TruckBuilder;
use DesignPatterns\Creational\Builder\CarBuilder;
use DesignPatterns\Creational\Builder\Director;
use PHPUnit\Framework\TestCase;
class DirectorTest extends TestCase
{
public function testCanBuildTruck()
{
$truckBuilder = new TruckBuilder();
$newVehicle = (new Director())->build($truckBuilder);
$this->assertInstanceOf(Truck::class, $newVehicle);
}
public function testCanBuildCar()
{
$carBuilder = new CarBuilder();
$newVehicle = (new Director())->build($carBuilder);
$this->assertInstanceOf(Car::class, $newVehicle);
}
}
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