Dependency Injection - Types

Types

Martin Fowler identifies three ways in which an object can get a reference to an external module, according to the pattern used to provide the dependency:

  • Type 1 or interface injection, in which the exported module provides an interface that its users must implement in order to get the dependencies at runtime.
  • Type 2 or setter injection, in which the dependent module exposes a setter method that the framework uses to inject the dependency.
  • Type 3 or constructor injection, in which the dependencies are provided through the class constructor.

It is possible for other frameworks to have other types of injection, beyond those presented above.

Read more about this topic:  Dependency Injection

Famous quotes containing the word types:

    The wider the range of possibilities we offer children, the more intense will be their motivations and the richer their experiences. We must widen the range of topics and goals, the types of situations we offer and their degree of structure, the kinds and combinations of resources and materials, and the possible interactions with things, peers, and adults.
    Loris Malaguzzi (1920–1994)

    Our children evaluate themselves based on the opinions we have of them. When we use harsh words, biting comments, and a sarcastic tone of voice, we plant the seeds of self-doubt in their developing minds.... Children who receive a steady diet of these types of messages end up feeling powerless, inadequate, and unimportant. They start to believe that they are bad, and that they can never do enough.
    Stephanie Martson (20th century)

    Science is intimately integrated with the whole social structure and cultural tradition. They mutually support one other—only in certain types of society can science flourish, and conversely without a continuous and healthy development and application of science such a society cannot function properly.
    Talcott Parsons (1902–1979)