1、模式定义

规格模式是组合模式的一种扩展，在框架性开发中使用较多（项目级开发很少使用），这里做一个简单的介绍。
规格模式（Specification）可以认为是组合模式的一种扩展。有时项目中某些条件决定了业务逻辑，这些条件就可以抽离出来以某种关系（与、或、非）进行组合，从而灵活地对业务逻辑进行定制。另外，在查询、过滤等应用场合中，通过预定义多个条件，然后使用这些条件的组合来处理查询或过滤，而不是使用逻辑判断语句来处理，可以简化整个实现逻辑。

这里的每个条件就是一个规格，多个规格/条件通过串联的方式以某种逻辑关系形成一个组合式的规格。

2、UML类图

3、示例代码

Item.php

<?phpnamespace DesignPatterns\Behavioral\Specification;class Item{protected $price;/*** An item must have a price** @param int $price*/public function __construct($price){$this->price = $price;}/*** Get the items price** @return int*/public function getPrice(){return $this->price;}}

SpecificationInterface.php

<?phpnamespace DesignPatterns\Behavioral\Specification;/*** 规格接口*/interface SpecificationInterface{/*** 判断对象是否满足规格** @param Item $item** @return bool*/public function isSatisfiedBy(Item $item);/*** 创建一个逻辑与规格（AND）** @param SpecificationInterface $spec*/public function plus(SpecificationInterface $spec);/*** 创建一个逻辑或规格（OR）** @param SpecificationInterface $spec*/public function either(SpecificationInterface $spec);/*** 创建一个逻辑非规格（NOT）*/public function not();}

AbstractSpecification.php

<?phpnamespace DesignPatterns\Behavioral\Specification;/*** 规格抽象类*/abstract class AbstractSpecification implements SpecificationInterface{/*** 检查给定Item是否满足所有规则** @param Item $item** @return bool*/abstract public function isSatisfiedBy(Item $item);/*** 创建一个新的逻辑与规格（AND）** @param SpecificationInterface $spec** @return SpecificationInterface*/public function plus(SpecificationInterface $spec){return new Plus($this, $spec);}/*** 创建一个新的逻辑或组合规格（OR）** @param SpecificationInterface $spec** @return SpecificationInterface*/public function either(SpecificationInterface $spec){return new Either($this, $spec);}/*** 创建一个新的逻辑非规格（NOT）** @return SpecificationInterface*/public function not(){return new Not($this);}}

Plus.php

<?phpnamespace DesignPatterns\Behavioral\Specification;/*** 逻辑与规格（AND）*/class Plus extends AbstractSpecification{protected $left;protected $right;/*** 在构造函数中传入两种规格** @param SpecificationInterface $left* @param SpecificationInterface $right*/public function __construct(SpecificationInterface $left, SpecificationInterface $right){$this->left = $left;$this->right = $right;}/*** 返回两种规格的逻辑与评估** @param Item $item** @return bool*/public function isSatisfiedBy(Item $item){return $this->left->isSatisfiedBy($item) && $this->right->isSatisfiedBy($item);}}

Either.php

<?phpnamespace DesignPatterns\Behavioral\Specification;/*** 逻辑或规格*/class Either extends AbstractSpecification{protected $left;protected $right;/*** 两种规格的组合** @param SpecificationInterface $left* @param SpecificationInterface $right*/public function __construct(SpecificationInterface $left, SpecificationInterface $right){$this->left = $left;$this->right = $right;}/*** 返回两种规格的逻辑或评估** @param Item $item** @return bool*/public function isSatisfiedBy(Item $item){return $this->left->isSatisfiedBy($item) || $this->right->isSatisfiedBy($item);}}

Not.php

<?phpnamespace DesignPatterns\Behavioral\Specification;/*** 逻辑非规格*/class Not extends AbstractSpecification{protected $spec;/*** 在构造函数中传入指定规格** @param SpecificationInterface $spec*/public function __construct(SpecificationInterface $spec){$this->spec = $spec;}/*** 返回规格的相反结果** @param Item $item** @return bool*/public function isSatisfiedBy(Item $item){return !$this->spec->isSatisfiedBy($item);}}

PriceSpecification.php

<?phpnamespace DesignPatterns\Behavioral\Specification;/*** 判断给定Item的价格是否介于最小值和最大值之间的规格*/class PriceSpecification extends AbstractSpecification{protected $maxPrice;protected $minPrice;/*** 设置最大值** @param int $maxPrice*/public function setMaxPrice($maxPrice){$this->maxPrice = $maxPrice;}/*** 设置最小值** @param int $minPrice*/public function setMinPrice($minPrice){$this->minPrice = $minPrice;}/*** 判断给定Item的定价是否在最小值和最大值之间** @param Item $item** @return bool*/public function isSatisfiedBy(Item $item){if (!empty($this->maxPrice) && $item->getPrice() > $this->maxPrice) {return false;}if (!empty($this->minPrice) && $item->getPrice() < $this->minPrice) {return false;}return true;}}

4、测试代码

Tests/SpecificationTest.php

<?phpnamespace DesignPatterns\Behavioral\Specification\Tests;use DesignPatterns\Behavioral\Specification\PriceSpecification;use DesignPatterns\Behavioral\Specification\Item;/*** SpecificationTest 用于测试规格模式*/class SpecificationTest extends \PHPUnit_Framework_TestCase{public function testSimpleSpecification(){$item = new Item(100);$spec = new PriceSpecification();$this->assertTrue($spec->isSatisfiedBy($item));$spec->setMaxPrice(50);$this->assertFalse($spec->isSatisfiedBy($item));$spec->setMaxPrice(150);$this->assertTrue($spec->isSatisfiedBy($item));$spec->setMinPrice(101);$this->assertFalse($spec->isSatisfiedBy($item));$spec->setMinPrice(100);$this->assertTrue($spec->isSatisfiedBy($item));}public function testNotSpecification(){$item = new Item(100);$spec = new PriceSpecification();$not = $spec->not();$this->assertFalse($not->isSatisfiedBy($item));$spec->setMaxPrice(50);$this->assertTrue($not->isSatisfiedBy($item));$spec->setMaxPrice(150);$this->assertFalse($not->isSatisfiedBy($item));$spec->setMinPrice(101);$this->assertTrue($not->isSatisfiedBy($item));$spec->setMinPrice(100);$this->assertFalse($not->isSatisfiedBy($item));}public function testPlusSpecification(){$spec1 = new PriceSpecification();$spec2 = new PriceSpecification();$plus = $spec1->plus($spec2);$item = new Item(100);$this->assertTrue($plus->isSatisfiedBy($item));$spec1->setMaxPrice(150);$spec2->setMinPrice(50);$this->assertTrue($plus->isSatisfiedBy($item));$spec1->setMaxPrice(150);$spec2->setMinPrice(101);$this->assertFalse($plus->isSatisfiedBy($item));$spec1->setMaxPrice(99);$spec2->setMinPrice(50);$this->assertFalse($plus->isSatisfiedBy($item));}public function testEitherSpecification(){$spec1 = new PriceSpecification();$spec2 = new PriceSpecification();$either = $spec1->either($spec2);$item = new Item(100);$this->assertTrue($either->isSatisfiedBy($item));$spec1->setMaxPrice(150);$spec2->setMaxPrice(150);$this->assertTrue($either->isSatisfiedBy($item));$spec1->setMaxPrice(150);$spec2->setMaxPrice(0);$this->assertTrue($either->isSatisfiedBy($item));$spec1->setMaxPrice(0);$spec2->setMaxPrice(150);$this->assertTrue($either->isSatisfiedBy($item));$spec1->setMaxPrice(99);$spec2->setMaxPrice(99);$this->assertFalse($either->isSatisfiedBy($item));}}

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