laravel-specification

An adaptation of the Specification Pattern as done by https://github.com/domnikl/DesignPatternsPHP, adding an artisan command to quickly create specifications.

Install

Via Composer (please change your minimum-stability to "dev")

$ composer require chalcedonyt/laravel-specification

Then run composer update. Once composer is finished, add the service provider to the providers array in app/config/app.php:

Chalcedonyt\Specification\Providers\SpecificationServiceProvider::class

Generating Specifications

An artisan command will be added to quickly create specifications.

php artisan make:specification [NameOfSpecification]

Adding a --parameters flag will prompts for parameters to be inserted into the constructor when generated:

Enter the class or variable name for parameter 0 (Examples: \App\User or $value) [Blank to stop entering parameters] [(no_param)]:
 > \App\User

 Enter the class or variable name for parameter 1 (Examples: \App\User or $value) [Blank to stop entering parameters] [(no_param)]:
 > $my_value

Results in

class NewSpecification extends AbstractSpecification
{

    /**
    * @var  \App\User
    */
    protected $user;

    /**
    * @var  
    */
    protected $myValue;


    /**
    *
    *  @param  \App\User $user
    *  @param   $myValue
    *
    */
    public function __construct(\App\User $user, $my_value)
    {
        $this->user = $user;
        $this->myValue = $my_value;
    }

    /**
    * Tests an object and returns a boolean value
    *
    * @var  mixed
    */

    public function isSatisfiedBy($candidate)
    {
        //return a boolean value
    }

}

Usage

class AgeOfPersonSpecification extends \Chalcedonyt\Specification\AbstractSpecification
{

    protected $minAge;
    protected $maxAge;

    /**
    * Set properties here for a parameterized specification.
    *
    */
    public function __construct($min_age, $max_age)
    {
        $this->minAge = $min_age;
        $this->maxAge = $max_age;
    }

    /**
    * Tests an object and returns a boolean value
    *
    * @var Array $candidate
    */

    public function isSatisfiedBy($candidate)
    {
        return $this->minAge <= $candidate['age'] && $this->maxAge >= $candidate['age'];
    }

}

class MalePersonSpecification  extends \Chalcedonyt\Specification\AbstractSpecification
{
    const GENDER_MALE = 1;
    const GENDER_FEMALE = 2;

    /**
    * Tests an object and returns a boolean value
    *
    * @var Array candidate
    */

    public function isSatisfiedBy($candidate)
    {
        return $candidate['gender'] == self::GENDER_MALE;
    }
}

$adult_spec = new AgeOfPersonSpecification(21, 80);
$teenager_spec = new AgeOfPersonSpecification(13, 19);
$puberty_spec = new AgeOfPersonSpecification(15, 19);

$male_spec = new MalePersonSpecification;
$female_spec = new NotSpec($male_spec);

$young_teenage_female = ['age' => 13, 'gender' => MalePersonSpecification::GENDER_FEMALE ];
$teenage_female = ['age' => 15, 'gender' => MalePersonSpecification::GENDER_FEMALE ];
$adult_female = ['age' => 22, 'gender' => MalePersonSpecification::GENDER_FEMALE ];

$nested_female_spec =  $puberty_spec->andSpec( $teenager_spec->andSpec( $female_spec ) );
$this->assertEquals( $nested_female_spec->isSatisfiedBy( $teenage_female ), true );
$this->assertEquals( $nested_female_spec->isSatisfiedBy( $young_teenage_female ), false );

$any_young_female_spec = $female_spec->andSpec( $teenager_spec->orSpec( $puberty_spec ));
$this->assertEquals( $nested_female_spec->isSatisfiedBy( $teenage_female ), true );
$this->assertEquals( $nested_female_spec->isSatisfiedBy( $adult_female ), false );

You may also retrieve unfulfilled specifications via the remainderUnsatisfiedBy property

$any_age_spec = new AgeOfPersonSpecification(1, 80);

$male_spec = new MalePersonSpecification;
$female_spec = new NotSpec($male_spec);

$male = ['age' => 16, 'gender' => MalePersonSpecification::GENDER_MALE ];

$any_young_female_spec = new AndSpec( $female_spec, $any_age_spec );
$this->assertEquals( $any_young_female_spec->isSatisfiedBy( $male ), false );

//returns the $female_spec
$unfulfilled_spec =  $any_young_female_spec->remainderUnsatisfiedBy( $male );
$inverse_female_spec = new NotSpec( $unfulfilled_spec );
$this->assertEquals( $inverse_female_spec->isSatisfiedBy( $male ), true );

Change log

• 0.4.4 You can now create a Specification inside a directory by specifying it in the classname, e.g. php artisan make:specification MyDir\\MySpec
• 0.4.2 Removed the isSatisfiedBy method from the abstract and interface. This allows type hinting on the $candidate.
• 0.4.1 Tweaked the generated views to use camel_case on any parameters.
• 0.4 Updated console command. You may now specify constructor parameters for the specification generator by entering the --parameters flag
• 0.3 Removed functionality to type-hint the argument to isSatisfiedBy, as PHP doesn't allow overloading abstract methods.
• 0.2 Added remainderUnsatisfiedBy functions

Testing

Credits

• Dominic Liebler [https://github.com/domnikl/DesignPatternsPHP]
• C# Specification Framework by Firzen [https://specification.codeplex.com/]
• The original Specification Pattern document by Eric Evans and Martin Fowler [http://www.martinfowler.com/apsupp/spec.pdf]

License

The MIT License (MIT). Please see License File for more information.