localheinz/specification

:blue_book: Provides specifications following the paper by Eric Evans and Martin Fowler.

specification

Provides specifications following the paper by Eric Evans and Martin Fowler, also see Wikipedia: Specification Pattern.

Installation

Run

$ composer require localheinz/specification

Usage

SpecificationInterface

Implement Localheinz\Specification\SpecificationInterface in your specifications:

namespace Foo\Bar;

use Localheinz\Specification\SpecificationInterface;

final class IsInstanceOfStdClass implements SpecificationInterface
{
    public function isSatisfiedBy($candidate): bool
    {
        return $candidate instanceof \stdClass;
    }
}

final class HasFooProperty implements SpecificationInterface
{
    public function isSatisfiedBy($candidate): bool
    {
        return property_exists($candidate, 'foo');
    }
}

final class HasBarProperty implements SpecificationInterface
{
    public function isSatisfiedBy($candidate): bool
    {
        return property_exists($candidate, 'bar');
    }
}

AndSpecification

Use Localheinz\Specification\AndSpecification to compose a specification from specifications which all need to be satisfied:

use Localheinz\Specification\AndSpecification;
use Localheinz\Specification\Test\Fixture;

$specification = new AndSpecification(
    new Fixture\Specification\IsInstanceOfStdClass(),
    new Fixture\Specification\HasFooProperty(),
    new Fixture\Specification\HasBarProperty()
);

$candidate = new \stdClass();

$candidate->foo = 9000;
$candidate->bar = 'Hello, my name is Jane';

$specification->isSatisfiedBy($candidate); // true

OrSpecification

Use Localheinz\Specification\OrSpecification to compose a specification from specifications where only one needs to be satisfied:

use Localheinz\Specification\OrSpecification;
use Localheinz\Specification\Test\Fixture;

$specification = new OrSpecification(
    new Fixture\Specification\IsInstanceOfStdClass(),
    new Fixture\Specification\HasFooProperty(),
    new Fixture\Specification\HasBarProperty()
);

$candidate = new \stdClass();

$specification->isSatisfiedBy($candidate); // true

NotSpecification

Use Localheinz\Specification\NotSpecification to compose a specification from specifications where none should be satisfied:

use Localheinz\Specification\NotSpecification;
use Localheinz\Specification\Test\Fixture;

$specification = new NotSpecification(
    new Fixture\Specification\IsInstanceOfStdClass(),
    new Fixture\Specification\HasFooProperty(),
    new Fixture\Specification\HasBarProperty()
);

$candidate = new \SplObjectStorage();

$specification->isSatisfiedBy($candidate); // true

Mix and match

Mix and match all of the specifications to your need:

use Localheinz\Specification\AndSpecification;
use Localheinz\Specification\NotSpecification;
use Localheinz\Specification\OrSpecification;
use Localheinz\Specification\Test\Fixture;

$specification = new AndSpecification(
    new NotSpecification(new Fixture\Specification\IsInstanceOfStdClass()),
    new OrSpecification(
        new Fixture\Specification\HasFooProperty(),
        new Fixture\Specification\HasBarProperty()
    )
);

class Baz
{
    public $foo;
}

$candidate = new Baz();

$specification->isSatisfiedBy($candidate); // true

Changelog

Please have a look at CHANGELOG.md.

Contributing

Please have a look at CONTRIBUTING.md.

Code of Conduct

Please have a look at CODE_OF_CONDUCT.md.

License

This package is licensed using the MIT License.