Renamed ProductCreateQuery to ProductCreatedQuery and updated rel…

…ated handler and decorator classes. Enhanced `IMediatorHandler` interface with XML documentation for clarity. Improved decorator methods in `ServiceCollectionExtensions` for better consistency and descriptiveness. These changes aim to enhance code clarity, maintainability, and functionality of the mediator pattern.

samples/MediatorSample/Program.cs

@@ -16,26 +16,39 @@
 services.AddMediatorHandler<ProductCreated, ProductCreatedHandler>()
         .Decorate<ProductCreatedDecorator>();
 
-services.AddMediatorHandler<ProductCreateQuery, string, ProductCreateQueryHandler>();
+services.AddMediatorHandler<ProductCreatedQuery, string, ProductCreatedQueryHandler>();
+services.DecorateMediatorHandler<ProductCreatedQuery, string, ProductCreatedQueryHandlerDecorator>();
 
 var serviceProvider = services.BuildServiceProvider();
 var mediator = serviceProvider.GetRequiredService<IMediator>();
 
 await mediator.SendAsync(new ProductCreated(1, "Product 1"));
-var result = await mediator.SendAsync<ProductCreateQuery, string>(new ProductCreateQuery());
+var result = await mediator.SendAsync<ProductCreatedQuery, string>(new ProductCreatedQuery());
 
 Console.WriteLine("Done");
 
-record ProductCreateQuery : IQuery;
+record ProductCreatedQuery : IQuery;
 
-class ProductCreateQueryHandler : IMediatorHandler<ProductCreateQuery, string>
+class ProductCreatedQueryHandler : IMediatorHandler<ProductCreatedQuery, string>
 {
-    public Task<Result<string>> HandleAsync(MediatorHandlerContext<ProductCreateQuery> context, CancellationToken cancellationToken = default)
+    public Task<Result<string>> HandleAsync(MediatorHandlerContext<ProductCreatedQuery> context, CancellationToken cancellationToken = default)
     {
+        Console.WriteLine("ProductCreatedQueryHandler:HandleAsync");
         return Task.FromResult(Result.Success("Product 1"));
     }
 }
 
+class ProductCreatedQueryHandlerDecorator(IMediatorHandler<ProductCreatedQuery, string> inner) : IMediatorHandler<ProductCreatedQuery, string>
+{
+    public async Task<Result<string>> HandleAsync(MediatorHandlerContext<ProductCreatedQuery> context, CancellationToken cancellationToken = default)
+    {
+        Console.WriteLine("ProductCreatedQueryHandlerDecorator:HandleAsync");
+        var result = await inner.HandleAsync(context, cancellationToken);
+        Console.WriteLine("ProductCreatedQueryHandlerDecorator:HandleAsync:Done");
+        return result;
+    }
+}
+
 public class LoggingMediator(IMediator inner) : IMediator
 {
     public async Task<Result> SendAsync<TRequest>(TRequest request, CancellationToken cancellationToken = default) where TRequest : class, ICommand

src/Infinity.Toolkit.Experimental/Mediator/Mediator.cs

@@ -9,28 +9,53 @@ public interface IQuery { }
 public interface IMediatorHandler<TIn>
     where TIn : class
 {
+    /// <summary>
+    /// Represents a handler for a request that does not return a result except for success or failure.
+    /// </summary>
+    /// <param name="context">The request context.</param>
+    /// <param name="cancellationToken">An optional cancellation token.</param>
+    /// <returns>Returns the result of the request.</returns>
     Task<Result> HandleAsync(MediatorHandlerContext<TIn> context, CancellationToken cancellationToken = default);
 }
 
 public interface IMediatorHandler<TIn, TResult>
     where TIn : class
 {
+    /// <summary>
+    /// Represents a handler for a request which returns a result.
+    /// </summary>
+    /// <param name="context">The request context.</param>
+    /// <param name="cancellationToken">An optional cancellation token.</param>
+    /// <returns>Returns the result of the request.</returns>
     Task<Result<TResult>> HandleAsync(MediatorHandlerContext<TIn> context, CancellationToken cancellationToken = default);
 }
 
 public interface IMediator
 {
+    /// <summary>
+    /// Sends a request to the mediator, the request is typically a command which does not return a result.
+    /// </summary>
+    /// <typeparam name="TRequest">The request type.</typeparam>
+    /// <param name="request">The content of the request.</param>
+    /// <param name="cancellationToken">An optional cancellation token.</param>
+    /// <returns>A success or failure result.</returns>
     Task<Result> SendAsync<TRequest>(TRequest request, CancellationToken cancellationToken = default)
         where TRequest : class, ICommand;
 
+    /// <summary>
+    /// Sends a request to the mediator, the request is typically a query which returns a result.
+    /// </summary>
+    /// <typeparam name="TRequest">The request type.</typeparam>
+    /// <typeparam name="TResponse">The response type.</typeparam>
+    /// <param name="request">The content of the request.</param>
+    /// <param name="cancellationToken">An optional cancellation token.</param>
+    /// <returns>The result of the request.</returns>
     Task<Result<TResponse>> SendAsync<TRequest, TResponse>(TRequest request, CancellationToken cancellationToken = default)
         where TRequest : class, IQuery;
 }
 
-public class Mediator(IServiceProvider serviceProvider) : IMediator
+internal sealed class Mediator(IServiceProvider serviceProvider) : IMediator
 {
-    private readonly IServiceProvider serviceProvider = serviceProvider;
-
     public Task<Result> SendAsync<TRequest>(TRequest request, CancellationToken cancellationToken = default)
         where TRequest : class, ICommand
     {

src/Infinity.Toolkit.Experimental/Mediator/ServiceCollectionExtensions.cs

@@ -8,8 +8,6 @@ public static class ServiceCollectionExtensions
     /// <summary>
     /// Adds the mediator to the service collection.
     /// </summary>
-    /// <param name="services"></param>
-    /// <returns></returns>
     public static IServiceCollection AddMediator(this IServiceCollection services)
     {
         services.TryAddTransient<IMediator, Mediator>();
@@ -22,7 +20,7 @@ public static IServiceCollection AddMediator(this IServiceCollection services)
     /// <typeparam name="TRequest">The request type.</typeparam>
     /// <typeparam name="TMediatorHandler">The mediator handler type.</typeparam>
     /// <param name="services">The service collection.</param>
-    /// <returns>A <see cref="MediatorHandlerBuilder"/> instance.</returns>
+    /// <returns>A <see cref="MediatorHandlerBuilder"/> instance used to configure the mediator handler.</returns>
     public static MediatorHandlerBuilder AddMediatorHandler<TRequest, TMediatorHandler>(this IServiceCollection services)
         where TRequest : class, ICommand
         where TMediatorHandler : class, IMediatorHandler<TRequest>
@@ -38,7 +36,7 @@ public static MediatorHandlerBuilder AddMediatorHandler<TRequest, TMediatorHandl
     /// <typeparam name="TResult">The result type.</typeparam>
     /// <typeparam name="TMediatorHandler">The mediator handler type.</typeparam>
     /// <param name="services">The service collection.</param>
-    /// <returns>A <see cref="MediatorHandlerBuilder"/> instance.</returns>
+    /// <returns>A <see cref="MediatorHandlerBuilder"/> instance used to configure the mediator handler.</returns>
     public static MediatorHandlerBuilder AddMediatorHandler<TRequest, TResult, TMediatorHandler>(this IServiceCollection services)
         where TRequest : class, IQuery
         where TMediatorHandler : class, IMediatorHandler<TRequest, TResult>
@@ -50,7 +48,8 @@ public static MediatorHandlerBuilder AddMediatorHandler<TRequest, TResult, TMedi
     /// <summary>
     /// Decorates all registered instance of <see cref="IMediatorHandler{TRequest}"/> using the specified type <typeparamref name="TDecorator"/>.
     /// </summary>
-    /// <param name="services">The services to add to.</param>
+    /// <typeparam name="TRequest">The request type.</typeparam>
+    /// <typeparam name="TDecorator">The decorator type.</typeparam>
     public static IServiceCollection DecorateMediatorHandler<TRequest, TDecorator>(this IServiceCollection services)
         where TDecorator : class, IMediatorHandler<TRequest>
         where TRequest : class, ICommand => services.Decorate<IMediatorHandler<TRequest>, TDecorator>();
@@ -59,11 +58,19 @@ public static IServiceCollection DecorateMediatorHandler<TRequest, TDecorator>(t
     /// Decorates all registered instance of <see cref="IMediatorHandler{TQuery, TQueryResult}"/> using the specified type <typeparamref name="TDecorator"/>.
     /// </summary>
     /// <param name="services">The services to add to.</param>
-    public static IServiceCollection DecorateMediatorHandler<TQuery, TQueryResult, TDecorator>(this IServiceCollection services)
-        where TDecorator : class, IMediatorHandler<TQuery, TQueryResult>
-        where TQuery : class, IQuery => services.Decorate<IMediatorHandler<TQuery, TQueryResult>, TDecorator>();
+    /// <typeparam name="TRequest">The request type.</typeparam>
+    /// <typeparam name="TResult">The result type.</typeparam>
+    /// <typeparam name="TDecorator">The decorator type.</typeparam>
+    public static IServiceCollection DecorateMediatorHandler<TRequest, TResult, TDecorator>(this IServiceCollection services)
+        where TDecorator : class, IMediatorHandler<TRequest, TResult>
+        where TRequest : class, IQuery => services.Decorate<IMediatorHandler<TRequest, TResult>, TDecorator>();
 }
 
+/// <summary>
+/// A builder used to configure a mediator handler.
+/// </summary>
+/// <param name="services"></param>
+/// <param name="handlerType"></param>
 public sealed class MediatorHandlerBuilder(IServiceCollection services, Type handlerType)
 {
     internal IServiceCollection Services { get; } = services;
@@ -73,9 +80,19 @@ public sealed class MediatorHandlerBuilder(IServiceCollection services, Type han
 
 public static class MediatorHandlerBuilderExtensions
 {
+    /// <summary>
+    /// Decorates all registered instances of <see cref="IMediatorHandler{TRequest}"/> using the specified type <typeparamref name="TDecorator"/>.
+    /// </summary>
+    /// <typeparam name="TDecorator">The decorator type.</typeparam>
+    /// <returns>A <see cref="MediatorHandlerBuilder"/> instance used to configure the mediator handler.</returns>
     public static MediatorHandlerBuilder Decorate<TDecorator>(this MediatorHandlerBuilder builder)
         where TDecorator : class => builder.Decorate(typeof(TDecorator));
 
+    /// <summary>
+    /// Decorates all registered instances of <see cref="IMediatorHandler{TRequest}"/> using the specified type <paramref name="decoratorType"/>.
+    /// </summary>
+    /// <param name="decoratorType">The decorator type.</param>
+    /// <returns>A <see cref="MediatorHandlerBuilder"/> instance used to configure the mediator handler.</returns>
     public static MediatorHandlerBuilder Decorate(this MediatorHandlerBuilder builder, Type decoratorType)
     {
         builder.Services.Decorate(builder.HandlerType, decoratorType);