Dependency injection
From CSSEMediaWiki
(Difference between revisions)
BenMcDonald (Talk | contribs) (New page: Dependency injection separates behaviour from dependency resolution. It is an alternative to the Factory pattern and hard coded dependencies. === Three examples of managing dependencies =...) |
BenMcDonald (Talk | contribs) m |
||
| Line 1: | Line 1: | ||
| − | Dependency | + | In the Dependency Injection pattern an object's dependencies are provided externally. This separates behaviour from dependency resolution. It is an alternative to the Factory pattern and hard coded dependencies. |
=== Three examples of managing dependencies === | === Three examples of managing dependencies === | ||
Revision as of 12:46, 30 August 2009
In the Dependency Injection pattern an object's dependencies are provided externally. This separates behaviour from dependency resolution. It is an alternative to the Factory pattern and hard coded dependencies.
Three examples of managing dependencies
A dependency hard coded into an object:
class SimpleCar implements Car
protected final Engine engine = new SimpleEngine()
public accelerate()
engine.setFuelValveIntake(gasPedalPressure)
Dependency from Factory pattern:
class SimpleCar implements Car
public accelerate()
engine = Factory.getEngine()
engine.setFuelValveIntake(gasPedalPressure)
Dependency Injection:
class SimpleCar implements Car
protected final Engine engine
public Car(Engine engine)
this.engine = engine
public accelerate()
engine.setFuelValveIntake(gasPedalPressure)
There are frameworks in all major languages for dependency injection. These frameworks let dependencies be defined with additional language syntax so that the framework can manage the dependencies.
