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
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