Dependency Inversion Rules

• Dependency Inversion Principle implies that high-level policies should not depend on low-level details

• Two major types of dependencies: stable and unstable (or volatile)

  • Unstable dependencies are those to which we want to apply the inversion of control

• What Inversion Of Control (IoC) and Dependency Injection are and how they are related to the Dependency Inversion Principle and to each other

• 3 techniques of DI

  • Constructor Injection, should be used 95% of the cases
  • Property Injection
  • Method injection

• Adhering to DIP leads to a [[plugin architecture]] which is known as the [[Ports and Adapters architecture]].

• There should be a single place which knows everything about application dependencies and their relationships and this is the [[Main partition]].
• Manual dependency injection may become tedious. That's why IoC-Containers exist, they help to simplify Dependency Injection in difficult cases.