pugx / godfather
Strategy pattern component as library and symfony2 bundle
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Requires
- php: >=5.3.0
Requires (Dev)
- phpunit/phpunit: 3.7.*
- symfony/dependency-injection: ~2.4
- symfony/framework-bundle: ~2.4
Suggests
- symfony/dependency-injection: if you want to use a proper dependency injection
README
The Strategy Pattern
http://en.wikipedia.org/wiki/Strategy_pattern
Intent
Define a family of algorithms, encapsulate each one, and make them interchangeable. Strategy lets the algorithm vary independently from clients that use it.
TL;DR
Given an object, you want to know its service.
eg. Entity\Mug
has a MugService
and Entity\Tshirt
has a TshirtService
$product = random(0,1)? new Entity\Mug: new Entity\Product $productService = $godfather->getStrategy('service', $product); // also works with $productService = $godfather->getService($product); echo get_class($productService); // will be randomly TshirtService or MugService
Sandbox
A working example is at example/godfather.php
cd example
php godfather.php
When do you need a strategist as Godfather?
- If you have a lot of classes that differs by their behaviour...
- If you have multiple conditional statements in order to define different behaviours...
- Given an object you want to know its manager/service/handler/provider/repository/...
Installation
composer require pugx/godfather ~0.1
A simple use case
The problem is that you have an object and you want to handle it properly.
How it works
This library does not try to duplicate the services, or to create a new container, but uses aliases in order to have a mapping between services and names.
An object is converted by the Context::getStrategyName
more info at changing the Context::Converter.
The smelling code
If your code look like this you will need the godfather's protection :)
// Pseudo Code class Cart function add(ProductInterface $product, OptionsInterface $options) { if ($product instanceOf Mug) { $item = $mugManager->add($options); } if ($product instanceOf Tshirt) { $item = $tshirtManager->add($options); } // ... }
The strategist
// Pseudo Code class Cart function add(ProductInterface $product, OptionsInterface $options) { $item = $this->godfather->getManager($product)->add($options); // ... }
GodFather and an array as DIC
$container = new Container\ArrayContainerBuilder(); $container->set('mug_service', new Your\MugService); $container->set('tshirt_service', new Your\TshirtService); $godfather = new Godfather($container, 'godfather'); $godfather->addStrategy('service', 'Mug', 'mug_service'); $godfather->addStrategy('service', 'Tshirt', 'tshirt_service'); // Step2. usage class Cart public function __construct($godfather) //... public function add(ProductInterface $product, OptionsInterface $options) { // get the strategy for cart with the context $product $service = $this->godfather->getStrategy('service', $product); // or $strategy = $this->godfather->getCart($product); return $strategy->addToCart($product, $options); }
GodFather and Symfony Dependency Injection Container
$container = new Container\ArrayContainerBuilder(); $loader = new Loader\XmlFileLoader($container, new FileLocator(__DIR__ . '/../Resources/config')); $loader->load('services.xml'); $godfather = new Godfather($container, 'godfather'); // Step2. usage class Cart public function __construct($godfather) //... public function add(ProductInterface $product, OptionsInterface $options) { // get the strategy for cart with the context $product $service = $this->godfather->getStrategy('service', $product); // or $strategy = $this->godfather->getService($product);
Using the Symfony2 Bundle
Install the Bundle
Add the bundle in the app/AppKernel.php
class AppKernel extends Kernel { public function registerBundles() { $bundles = array( ... new PUGX\GodfatherBundle\GodfatherBundle(),
Configuring app/config/config.yml
Minimal Configuration
# add the below configuration only if you need to specify the fallback or the interface. godfather: default: contexts: manager: ~ # your strategy name
With the fallback strategy
# add the below configuration only if you need to specify the fallback or the interface. godfather: default: contexts: manager: fallback: manager_standard # need a reference to a defined service
Set your strategies:
parameters: mug.class: Mug tshirt.class: Tshirt services: manager_standard: class: StandardProductManager manager_mug: class: MugManager tags: - { name: godfather.strategy, context_name: 'manager', context_key: %mug.class% } manager_tshirt: class: TshirtManager tags: - { name: godfather.strategy, context_name: 'manager', context_key: %tshirt.class% }
Using in the controller:
$product = new \Product\ShoeProduct(); $manager = $container->get('godfather')->getManager($product); // or $manager = $container->get('godfather')->getStrategy('manager', $product); // then $manager->doSomethingGreat();
Advanced with multiple instances
Instead of default you could configure your strategy in different godfather instances.
godfather: death: contexts: manager: ~ life: contexts: manager: ~
the strategies:
services: manager.entity_life: class: EntityProductManager arguments: ['life'] tags: - { name: godfather.strategy, instance:'life', context_name: 'manager', context_key: %product.show.class% } manager.entity_death: class: EntityProductManager arguments: ['death'] tags: - { name: godfather.strategy, instance:'death', context_name: 'manager', context_key: %product.show.class% }
and then the code with multiple instances
$this->getContainer('godfather.life')->getManager($entity); $this->getContainer('godfather.death')->getManager($entity);
Changing the Context::Converter
The Godfather\Context\Context::getStrategyName
transforms an object into a strategy name,
the default one just extract from the $object the short class name.
If you want another converter create your class extends the ContextInterface and then:
godfather: deafault: contexts: manager: class: \My\Context
Contribution
Active contribution and patches are very welcome. To keep things in shape we have quite a bunch of unit tests. If you're submitting pull requests please make sure that they are still passing and if you add functionality please take a look at the coverage as well it should be pretty high :)
composer create-project pugx/godfather --dev -s dev
cd godfather
bin/phpunit