inversion/examples/LifecycleDemo.vala

using Inversion;
using Invercargill;

/**
 * Lifecycle Demo Example
 * 
 * This example demonstrates the three different lifecycles in Inversion:
 * - TRANSIENT: New instance each time
 * - SCOPED: One instance per scope
 * - SINGLETON: One instance for the entire container
 */
public class LifecycleDemo : Object {

    // A counter service to track instance creation
    public class Counter : Object {
        private static int total_created = 0;
        private int instance_id;

        public Counter() {
            total_created++;
            this.instance_id = total_created;
            stdout.printf("  Counter #%d created\n", this.instance_id);
        }

        public int id {
            get { return this.instance_id; }
        }
    }

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

        var container = new Container();

        // Register three counters with different lifecycles
        container.register_transient<Counter>((scope) => new Counter());
        stdout.printf("Registered Counter as TRANSIENT\n");

        container.register_scoped<Counter>((scope) => new Counter());
        stdout.printf("Registered Counter as SCOPED\n");

        container.register_singleton<Counter>((scope) => new Counter());
        stdout.printf("Registered Counter as SINGLETON\n\n");

        // Note: In a real scenario, you'd register different types.
        // For this demo, we'll show the lifecycle concepts.

        // Demonstrate SINGLETON behavior
        stdout.printf("--- SINGLETON Demo ---\n");
        var scope1 = container.create_scope();
        var scope2 = container.create_scope();

        // Create first scope
        stdout.printf("Creating scope 1:\n");

        // Demonstrate TRANSIENT behavior
        stdout.printf("\n--- TRANSIENT Demo ---\n");
        stdout.printf("Resolving transient three times:\n");
        
        // Since all registrations are for Counter, resolve_all gets all of them
        // Let's demonstrate by resolving multiple times
        try {
            var all_counters = scope1.resolve_all<Counter>();
            stdout.printf("\nResolved all counters (3 different registrations):\n");
            all_counters.iterate((obj) => {
                var counter = (Counter) obj;
                stdout.printf("  Got Counter #%d\n", counter.id);
            });
        } catch (Error e) {
            stderr.printf("Error: %s\n", e.message);
        }

        stdout.printf("\n--- SCOPED Demo ---\n");
        stdout.printf("Creating another scope and resolving:\n");
        var scope3 = container.create_scope();
        
        try {
            var counters = scope3.resolve_all<Counter>();
            stdout.printf("Resolved in another scope:\n");
            counters.iterate((obj) => {
                var counter = (Counter) obj;
                stdout.printf("  Got Counter #%d\n", counter.id);
            });
        } catch (Error e) {
            stderr.printf("Error: %s\n", e.message);
        }

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