The ServiceManager is a Service Locator implementation. A Service Locator is a well-known object in which you may register objects and later retrieve them. The implementation within Zend Framework provides 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’, ‘FullyQualifiedClassname’)).
  • 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.

Your typical interaction with a ServiceManager, however, will be via two methods:

  • has($name), for testing whether the ServiceManager has a named service;
  • get($name), for retrieving a service by the given name.