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:

    He types his laboured column—weary drudge!
    Senile fudge and solemn:
    Spare, editor, to condemn
    These dry leaves of his autumn.
    Robertson Davies (b. 1913)

    The bourgeoisie loves so-called “positive” types and novels with happy endings since they lull one into thinking that it is fine to simultaneously acquire capital and maintain one’s innocence, to be a beast and still be happy.
    Anton Pavlovich Chekhov (1860–1904)

    If there is nothing new on the earth, still the traveler always has a resource in the skies. They are constantly turning a new page to view. The wind sets the types on this blue ground, and the inquiring may always read a new truth there.
    Henry David Thoreau (1817–1862)