inversion/examples/BasicUsage.vala

using Inversion;

/**
 * Basic Usage Example
 * 
 * This example demonstrates the fundamental features of the Inversion IoC container:
 * - Registering types with different lifecycles
 * - Resolving dependencies
 * - Using the type-safe resolve methods
 */
public class BasicUsageExample : Object {

    // Define a simple service interface
    public interface ILogger : Object {
        public abstract void log(string message);
    }

    // Console logger implementation
    public class ConsoleLogger : Object, ILogger {
        public void log(string message) {
            stdout.printf("[LOG] %s\n", message);
        }
    }

    // A service that depends on ILogger
    public class UserService : Object {
        private ILogger logger;

        public UserService(ILogger logger) {
            this.logger = logger;
        }

        public void greet(string name) {
            this.logger.log(@"Hello, $name!");
        }
    }

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

        // Create the container
        var container = new Container();

        // Register the logger as a singleton with a factory delegate
        container.register_singleton<ConsoleLogger>((scope) => new ConsoleLogger())
            .as_type(typeof(ILogger));

        stdout.printf("Registered ConsoleLogger as ILogger (Singleton)\n\n");

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

        // Resolve the logger using type-safe method
        try {
            var logger = scope.resolve<ILogger>();
            logger.log("Logger resolved successfully!");

            // Resolve again to demonstrate singleton behavior
            var logger2 = scope.resolve<ILogger>();
            logger2.log("Second resolution - same instance!");

            // Verify they are the same instance
            if (logger == logger2) {
                stdout.printf("\n✓ Singleton working: Both references point to the same instance\n");
            }
        } catch (Error e) {
            stderr.printf("Error: %s\n", e.message);
            return 1;
        }

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