Zend\ServiceManager

Zend\ServiceManager

The Service Locator design pattern is implemented by the ServiceManager. The Service Locator is a service/object locator, tasked with retrieving other objects. You may interact with the ServiceManager via the following methods

// /library/Zend/ServiceManager/ServiceLocatorInterface.php
      namespace Zend\ServiceManager;

      interface ServiceLocatorInterface
      {
              public function get($name);
              public function has($name);
      }
  • has($name), tests whether the ServiceManager has a named service;
  • get($name), retrieves a service by the given name.

In addition to above methods, the ServiceManager can be instantiated via the following features:

  • Service registration. You can register an object under a given name $services->setService('foo', $object).
  • Lazy-loaded service objects. You can tell the manager what class to instantiate on first request $services->setInvokableClass('foo', 'Fully\Qualified\Classname').
  • Service factories. Instead of an actual object instance or a class name, you can tell the manager to invoke the provided factory in order to get the object instance. Factories may be either any PHP callable, an object implementing Zend\ServiceManager\FactoryInterface, or the name of a class implementing that interface.
  • Service aliasing. You can tell the manager that when a particular name is requested, use the provided name instead. You can alias to a known service, a lazy-loaded service, a factory, or even other aliases.
  • Abstract factories. An abstract factory can be considered a “fallback” – if the service does not exist in the manager, it will then pass it to any abstract factories attached to it until one of them is able to return an object.
  • Initializers. You may want certain injection points always populated – as an example, any object you load via the service manager that implements Zend\EventManager\EventManagerAware should likely receive an EventManager instance. Initializers are PHP callbacks or classes implementing Zend\ServiceManager\InitializerInterface; they receive the new instance, and can then manipulate it.

In addition to the above, the ServiceManager also provides optional ties to Zend\Di, allowing Di to act as an initializer or an abstract factory for the manager.

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