basic

README

Basic Example

This example demonstrates the core functionality of the gioc package.

What it demonstrates

• Registering constructors with gioc.Register()
• Automatic constructor injection (parameters resolved from the container)
• Singleton behavior – constructors are called only once
• Startup validation with gioc.Validate()
• Retrieving instances with gioc.Get[T]()

Code explanation

The example creates a three-layer dependency chain using the global default container:

1. UserRepository – data access layer (no dependencies)
2. UserService – depends on *UserRepository
3. UserHandler – depends on *UserService

All constructors are registered up front. Validate() checks for missing dependencies and cycles at startup. When Get[*UserHandler]() is called, the container resolves the full dependency chain automatically, creating each component exactly once.

Output

NewUserRepository called
NewUserService called
NewUserHandler called
handler1 == handler2: true (singleton)

Each constructor runs once. Both handler1 and handler2 point to the same instance.