PHP Design Mode Series Specification Specification mode _php instance

1. Pattern definition

Specification mode is an extension of the combined pattern, which is used more in framework development (project-level development is seldom used), and a simple introduction is made here.
The specification mode (specification) can be considered as an extension of the combined pattern. Sometimes the business logic is determined by certain conditions in the project that can be drawn out to be combined in a relationship (with, or, or not) to flexibly customize the business logic. In addition, in applications such as query, filter, and so on, it is possible to simplify the whole implementation logic by predefined multiple conditions and then using the combination of these conditions to process queries or filters instead of using logical judgment statements.

Each of these conditions is a specification, and multiple specifications/conditions form a modular specification in a logical relationship in a series of ways.

2. UML Class Diagram

3. Sample Code

item.php

<?phpnamespace designpatterns\behavioral\specification;class item{protected $price;/*** an Item must has 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;/*** Specification Interface */interface specificationinterface{/*** Determine if the object meets specifications * * @param item $item * * @return bool*/public function IsSatisfiedBy (Item $item);/*** Create a logic and specification (and) * * @param Spe Cificationinterface $spec */public function Plus (specificationinterface $spec)/*** Create a logical or specification (OR) * * @param Specificationinterface $spec */public function either (Specificationinterface $spec);/*** Create a logical non-specification (not) */public function not ();}

abstractspecification.php

<?phpnamespace designpatterns\behavioral\specification;/*** Specification Abstract classes */abstract class Abstractspecification Implements specificationinterface{/*** checks whether the given item satisfies all rules * * @param Item $item * * @return bool*/abstract Public function IsSatisfiedBy (Item $item);/*** creates a new logic and specification (and) * * @param specificationinterface $spec * * @return Specificationinterface*/public function Plus (Specificationinterface $spec) {return new Plus ($this, $spec);} /*** Create a new logical OR combination specification (OR) * * @param specificationinterface $spec * * @return specificationinterface*/public function either ( Specificationinterface $spec) {return new either ($this, $spec);} /*** Create a new logical non-specification (not) * * @return Specificationinterface*/public Function not () {return new not ($this);}}

plus.php

<?phpnamespace designpatterns\behavioral\specification;/*** Logic and Specifications (and) */class Plus extends Abstractspecification {protected $left;p rotected $right;/*** passed in the constructor in two sizes * * @param specificationinterface $left * @param Specificationinterface $right */public function __construct (specificationinterface $left, Specificationinterface $ right) {$this->left = $left; $this->right = $right;} /*** returns the logic and evaluation of both specifications * * @param item $item * * @return bool*/public function IsSatisfiedBy (Item $item) {return $this->left-& Gt;issatisfiedby ($item) && $this->right->issatisfiedby ($item);}

either.php

<?phpnamespace designpatterns\behavioral\specification;/*** logic or specification */class either extends abstractspecification{ Protected $left;p rotected $right/*** two combinations of specifications * * @param specificationinterface $left * @param specificationinterface $ Right*/public function __construct (specificationinterface $left, Specificationinterface $right) {$this->left = $ Left; $this->right = $right;} /*** returns the logic or evaluation of both specifications * * @param item $item * * @return bool*/public function IsSatisfiedBy (Item $item) {return $this->left-& Gt;issatisfiedby ($item) | | $this->right->issatisfiedby ($item);}}

not.php

<?phpnamespace designpatterns\behavioral\specification;/*** Logic Non-specification */class not extends abstractspecification{ protected $spec;/*** Pass in the constructor with the specified specification * * @param specificationinterface $spec */public function __construct ( Specificationinterface $spec) {$this->spec = $spec;} /*** returns the opposite result of the specification * * @param item $item * * @return bool*/public function IsSatisfiedBy (item $item) {return! $this->spec-> IsSatisfiedBy ($item);}}

pricespecification.php

<?phpnamespace designpatterns\behavioral\specification;/*** Determines whether the price of a given item is between the minimum and maximum values */class Pricespecification extends abstractspecification{protected $maxPrice;p rotected $minPrice;/*** Set maximum * * @param int $ Maxprice*/public function Setmaxprice ($maxPrice) {$this->maxprice = $maxPrice;} /*** Set Minimum Value * * @param int $minPrice */public function Setminprice ($minPrice) {$this->minprice = $minPrice;} /*** determines whether the pricing for a given Item is between the minimum and maximum values * * @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. Test code

tests/specificationtest.php

<?phpnamespace Designpatterns\behavioral\specification\tests;use designpatterns\behavioral\specification\ Pricespecification;use designpatterns\behavioral\specification\item;/*** specificationtest for test specification mode */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, $this->asserttrue ($spec- >issatisfiedby ($item)); $spec->setminprice (101); $this->assertfalse ($spec->issatisfiedby ($item)); $ Spec->setminprice, $this->asserttrue ($spec->issatisfiedby ($item));} Public Function testnotspecification () {$item = new Item, $spec = new Pricespecification (); $not = $spec->not (); $ This->assertfalse ($not->issatisfiedby ($item)), $spec->setmaxprice, $this->asserttrue ($not IsSatisfiedBy ($item)); $spec->sEtmaxprice, $this->assertfalse ($not->issatisfiedby ($item)), $spec->setminprice (101); $this Asserttrue ($not->issatisfiedby ($item)), $spec->setminprice, $this->assertfalse ($not, IsSatisfiedBy ($item));} Public Function testplusspecification () {$spec 1 = new pricespecification (); $spec 2 = new Pricespecification (); $plus = $ Spec1->plus ($spec 2); $item = new Item, $this->asserttrue ($plus->issatisfiedby ($item)); $spec 1-> Setmaxprice, $spec 2->setminprice, $this->asserttrue ($plus->issatisfiedby ($item)); $spec 1-> Setmaxprice, $spec 2->setminprice (101), $this->assertfalse ($plus->issatisfiedby ($item)); $spec 1-> Setmaxprice, $spec 2->setminprice, $this->assertfalse ($plus->issatisfiedby ($item));} Public Function testeitherspecification () {$spec 1 = new pricespecification (); $spec 2 = new Pricespecification (); $either = $spec 1->either ($spec 2); $item = new Item, $this->asserttrue ($either->issatisfiedby ($item)); $spec 1->setmaxprice, $spec 2->setmaxprice, $this->asserttrue ($either->issatisfiedby ($item)); Spec1->setmaxprice, $spec 2->setmaxprice (0), $this->asserttrue ($either->issatisfiedby ($item)); Spec1->setmaxprice (0), $spec 2->setmaxprice, $this->asserttrue ($either->issatisfiedby ($item)); Spec1->setmaxprice, $spec 2->setmaxprice, $this->assertfalse ($either->issatisfiedby ($item));}}

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