Trait ServiceToken

Source

pub trait ServiceToken:
    Send
    + Sync
    + 'static {
    type Service: ?Sized + Send + Sync + 'static;

    // Provided methods
    fn service_type_id() -> TypeId
       where Self::Service: 'static { ... }
    fn service_type_name() -> &'static str { ... }
    fn token_type_name() -> &'static str { ... }
}

Expand description

Trait for service tokens that provide compile-time trait-to-implementation mapping

Service tokens are zero-sized types that act as compile-time identifiers for specific services or traits. They enable type-safe dependency resolution through semantic naming rather than concrete type dependencies.

§Design Principles

Zero Runtime Cost: Tokens are zero-sized and only exist at compile time
Type Safety: Prevents incorrect service resolution through type constraints
Semantic Naming: Enables meaningful service identifiers like EmailNotificationToken
Trait Resolution: Allows injection of trait objects rather than concrete types

§Implementation Requirements

Token must be a zero-sized struct
Associated Service type must be Send + Sync + 'static
Service type is typically a trait object (dyn Trait)

§Examples

§Basic Trait Token

use elif_core::container::ServiceToken;
 
trait Database: Send + Sync {}
struct DatabaseToken;
impl ServiceToken for DatabaseToken {
    type Service = dyn Database;
}

§Specialized Service Token

use elif_core::container::ServiceToken;
 
trait CacheService: Send + Sync {
    fn get(&self, key: &str) -> Option<String>;
}
 
struct CacheToken;
impl ServiceToken for CacheToken {
    type Service = dyn CacheService;
}

struct RedisCache;
impl CacheService for RedisCache {
    fn get(&self, _key: &str) -> Option<String> {
        None // Mock implementation
    }
}