inversion/examples/MultiRegistration.vala

using Inversion;
using Invercargill;

/**
 * Multi-Registration Example
 * 
 * This example demonstrates:
 * - Registering multiple implementations for the same interface
 * - Using resolve_all<T>() to get all implementations
 * - Using custom factory delegates
 */
public class MultiRegistrationExample : Object {

    // Define a handler interface
    public interface IHandler : Object {
        public abstract string name { get; }
        public abstract void handle(string request);
    }

    // First handler implementation
    public class AuthHandler : Object, IHandler {
        public string name { get { return "Auth"; } }

        public void handle(string request) {
            stdout.printf("  [AuthHandler] Processing: %s\n", request);
        }
    }

    // Second handler implementation
    public class LoggingHandler : Object, IHandler {
        public string name { get { return "Logging"; } }

        public void handle(string request) {
            stdout.printf("  [LoggingHandler] Processing: %s\n", request);
        }
    }

    // Third handler implementation with custom configuration
    public class CacheHandler : Object, IHandler {
        private int ttl_seconds;

        public CacheHandler(int ttl_seconds) {
            this.ttl_seconds = ttl_seconds;
        }

        public string name { get { return "Cache"; } }

        public void handle(string request) {
            stdout.printf("  [CacheHandler] Processing: %s (TTL: %ds)\n", request, this.ttl_seconds);
        }
    }

    public static int main(string[] args) {
        stdout.printf("=== Inversion IoC Multi-Registration Example ===\n\n");

        var container = new Container();

        // Register multiple handlers for the same interface with factory delegates
        container.register_singleton<AuthHandler>((scope) => new AuthHandler())
            .as_type(typeof(IHandler));
        stdout.printf("Registered AuthHandler as IHandler (Singleton)\n");

        container.register_singleton<LoggingHandler>((scope) => new LoggingHandler())
            .as_type(typeof(IHandler));
        stdout.printf("Registered LoggingHandler as IHandler (Singleton)\n");

        // Register with a custom factory delegate that requires parameters
        container.register_singleton<CacheHandler>((scope) => {
            return new CacheHandler(300); // 5 minute TTL
        })
            .as_type(typeof(IHandler));
        stdout.printf("Registered CacheHandler as IHandler (with custom factory)\n\n");

        // Create a scope
        var scope = container.create_scope();

        // Resolve a single handler (gets any one)
        stdout.printf("--- Resolving Single Handler ---\n");
        try {
            var handler = scope.resolve<IHandler>();
            stdout.printf("Got single handler: %s\n", handler.name);
        } catch (Error e) {
            stderr.printf("Error: %s\n", e.message);
        }

        // Resolve all handlers
        stdout.printf("\n--- Resolving All Handlers ---\n");
        var handlers = scope.resolve_all<IHandler>();
        
        stdout.printf("Processing request through all handlers:\n");
        handlers.iterate((obj) => {
            var handler = (IHandler) obj;
            handler.handle("GET /api/users");
        });

        // Show count
        var count = handlers.count();
        stdout.printf("\nTotal handlers resolved: %u\n", count);

        stdout.printf("\n=== Multi-Registration Example Complete ===\n");
        return 0;
    }
}