This document discusses dependency injection and inversion of control. It provides an agenda for covering common vocabulary, why use dependency injection, implementing it from scratch, and taking questions. The speaker will define terms like direct control, object graph, inversion of control, container, composite root, and lifecycle. Benefits highlighted include making code more testable, loosely coupled, and evolvable by removing direct dependencies and allowing for abstraction. Rolling their own dependency injection is presented as simpler than using a container but also potentially more complex.

1. @NathanGloyn nathans.dropbox@gmail.com
Design Code Release nathangloyn
Inversion of Control
Containers Vs. hand
rolled
How they compare

2. Agenda
• A common vocabulary
• Why use dependency injection
• From scratch(ish)
• Summary
• Questions

3. A common
vocabulary

4. Direct control

5. Object Graph
Data Access
Repository
Controller Repository Data Access
Service Repository Data Access
Repository Data Access

6. Inversion of Control

7. Container

8. Composite Root

9. Lifecycle

10. Why use dependency
injection?

11. Testable
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12. Loosely coupled

13. Evolvable

14. Code
From
Scratch(ish)

15. Summary
• IoC not always needed
• Easy to implement IoC
• Removes complexity
• Can add complexity

16. Questions