Charcoal Factory

The Factory package provides abstract object factories to create objects.

Installation

composer require charcoal/factory

Usage

Factories can resolve a type to a FQN and create instance of this class with an optional given set of arguments, while ensuring a default base class.

Factory options should be set directly from the constructor:

$factory = new Charcoal\Factory\GenericFactory([
    // Ensure the created object is a Charcoal Model
    'base_class' => '\Charcoal\Model\ModelInterface',

    // An associative array of class map (aliases)
    'map' => [
        'foo' => '\My\Foo',
        'bar' => '\My\Bar',
    ],

    // Constructor arguments
    'arguments' => [
        $dep1,
        $dep2,
    ],

    // Object callback
    'callback' => function ($obj) {
        $obj->do('foo');
    },
]);

// Create a "\My\Custom\Baz" object with the given arguments + callbck
$factory->create('\My\Custom\Baz');

// Create a "\My\Foo" object (using the map of aliases)
$factory->create('foo');

// Create a "\My\Custom\FooBar" object with the default resolver
$factory->create('my/custom/foo-bar');

Constructor options (class dependencies) are:

Name	Type	Default	Description
base_class	string	''	Optional. A base class (or interface) to ensure a type of object.
default_class	string	''	Optional. A default class, as fallback when the requested object is not resolvable.
arguments	array	[]	Optional. Constructor arguments that will be passed along to created instances.
callback	callable	null	Optional. A callback function that will be called upon object creation.
resolver	callable	null[1]	Optional. A class resolver. If none is provided, a default will be used.
resolver_options	array	null	Optional. Resolver options (prefix, suffix, capitals and replacements). This is ignored / unused if resolver is provided.

Notes:

• ^[1] If no resolver is provided, a default \Charcoal\Factory\GenericResolver will be used.

Class resolver

The type (class identifier) sent to the create() method can be parsed / resolved with a custom Callable resolver.

If no resolver is passed to the constructor, a default \Charcoal\Factory\GenericResolver is used. This default resolver transforms, for example, my/custom/foo-bar into \My\Custom\FooBar.

Class map and aliases

Class aliases can be added by setting them in the Factory constructor:

$factory = new GenericFactory([
    'map' => [
        'foo' => '\My\Foo',
        'bar' => '\My\Bar',
    ],
]);

// Create a `\My\Foo` instance
$obj = $factory->create('foo');

Ensuring a type of object

Ensuring a type of object can be done by setting the base_class property.

The recommended way of setting the base class is by setting it in the constructor:

$factory = new GenericFactory([
    'base_class' => '\My\Foo\BaseClassInterface',
]);

👉 Note that Interfaces can also be used as a factory's base class.

Setting a default type of object

It is possible to set a default type of object (default class) by setting the default_class property.

The recommended way of setting the default class is by setting it in the constructor:

$factory = new GenericFactory([
    'default_class' => '\My\Foo\DefaultClassInterface',
]);

⚠️ Setting a default class name changes the standard Factory behavior. When an invalid class name is used, instead of throwing an Exception, an object of the default class type will always be returned.

Constructor arguments

It is possible to set "automatic" constructor arguments that will be passed to every created object.

The recommended way of setting constructor arguments is by passing an array of arguments to the constructor:

$factory = new GenericFactory([
    'arguments' => [
        [
            'logger' => $container['logger'],
        ],
        $secondArgument,
    ],
]);

Executing an object callback

It is possible to execute an object callback upon object instanciation. A callback is any Callable that takes the newly created object by reference as its function parameter.

// $obj is the newly created object
function callback($obj): void;

The recommended way of adding an object callback is by passing a Callable to the constructor:

$factory = new GenericFactory([
    'arguments' => [[
        'logger' => $container['logger']
    ]],
    'callback' => function ($obj) {
        $obj->foo('bar');
        $obj->logger->debug('Objet instanciated from factory.');
    }
]);

Resources

• Contributing
• Report issues and send pull requests in the main Charcoal repository