構(gòu)建清晰的業(yè)務(wù)規(guī)則規(guī)范,在其中可以對(duì)對(duì)象進(jìn)行檢查。每個(gè)規(guī)范類有一個(gè)名為[isSatisfiedBy]的方法,根據(jù)給定對(duì)象是否滿足規(guī)范返回true或false。
UML 圖
Item.php
<?php declare(strict_types=1); namespace DesignPatterns\Behavioral\Specification; class Item { public function __construct(private float $price) { } public function getPrice(): float { return $this->price; } }
Specification.php
<?php declare(strict_types=1); namespace DesignPatterns\Behavioral\Specification; interface Specification { public function isSatisfiedBy(Item $item): bool; }
OrSpecification.php
<?php declare(strict_types=1); namespace DesignPatterns\Behavioral\Specification; class OrSpecification implements Specification { /** * @var Specification[] */ private array $specifications; /** * @param Specification[] $specifications */ public function __construct(Specification ...$specifications) { $this->specifications = $specifications; } /* * if at least one specification is true, return true, else return false */ public function isSatisfiedBy(Item $item): bool { foreach ($this->specifications as $specification) { if ($specification->isSatisfiedBy($item)) { return true; } } return false; } }
PriceSpecification.php
<?php declare(strict_types=1); namespace DesignPatterns\Behavioral\Specification; class PriceSpecification implements Specification { public function __construct(private ?float $minPrice, private ?float $maxPrice) { } public function isSatisfiedBy(Item $item): bool { if ($this->maxPrice !== null && $item->getPrice() > $this->maxPrice) { return false; } if ($this->minPrice !== null && $item->getPrice() < $this->minPrice) { return false; } return true; } }
AndSpecification.php
<?php declare(strict_types=1); namespace DesignPatterns\Behavioral\Specification; class AndSpecification implements Specification { /** * @var Specification[] */ private array $specifications; /** * @param Specification[] $specifications */ public function __construct(Specification ...$specifications) { $this->specifications = $specifications; } /** * if at least one specification is false, return false, else return true. */ public function isSatisfiedBy(Item $item): bool { foreach ($this->specifications as $specification) { if (!$specification->isSatisfiedBy($item)) { return false; } } return true; } }
NotSpecification.php
<?php declare(strict_types=1); namespace DesignPatterns\Behavioral\Specification; class NotSpecification implements Specification { public function __construct(private Specification $specification) { } public function isSatisfiedBy(Item $item): bool { return !$this->specification->isSatisfiedBy($item); } }
Tests/SpecificationTest.php
<?php declare(strict_types=1); namespace DesignPatterns\Behavioral\Specification\Tests; use DesignPatterns\Behavioral\Specification\Item; use DesignPatterns\Behavioral\Specification\NotSpecification; use DesignPatterns\Behavioral\Specification\OrSpecification; use DesignPatterns\Behavioral\Specification\AndSpecification; use DesignPatterns\Behavioral\Specification\PriceSpecification; use PHPUnit\Framework\TestCase; class SpecificationTest extends TestCase { public function testCanOr() { $spec1 = new PriceSpecification(50, 99); $spec2 = new PriceSpecification(101, 200); $orSpec = new OrSpecification($spec1, $spec2); $this->assertFalse($orSpec->isSatisfiedBy(new Item(100))); $this->assertTrue($orSpec->isSatisfiedBy(new Item(51))); $this->assertTrue($orSpec->isSatisfiedBy(new Item(150))); } public function testCanAnd() { $spec1 = new PriceSpecification(50, 100); $spec2 = new PriceSpecification(80, 200); $andSpec = new AndSpecification($spec1, $spec2); $this->assertFalse($andSpec->isSatisfiedBy(new Item(150))); $this->assertFalse($andSpec->isSatisfiedBy(new Item(1))); $this->assertFalse($andSpec->isSatisfiedBy(new Item(51))); $this->assertTrue($andSpec->isSatisfiedBy(new Item(100))); } public function testCanNot() { $spec1 = new PriceSpecification(50, 100); $notSpec = new NotSpecification($spec1); $this->assertTrue($notSpec->isSatisfiedBy(new Item(150))); $this->assertFalse($notSpec->isSatisfiedBy(new Item(50))); } }
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