#34991 Mediator pattern.

src/mediator/Mediator.Step0/ILoggingService.cs

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+// Copyright (c) SharpCrafters s.r.o. See the LICENSE.md file in the root directory of this repository root for details.
+
+public interface ILoggingService
+{
+    void Log(string message );
+}

src/mediator/Mediator.Step0/IMetricService.cs

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+// Copyright (c) SharpCrafters s.r.o. See the LICENSE.md file in the root directory of this repository root for details.
+
+namespace Mediator;
+
+public interface IMetricService
+{
+    void ItemDistributed( IWarehouse warehouse, Item item, IStore store );
+    void ItemReceived( IStore store, Item item );
+    void ItemReturned( IStore store, Item item, IWarehouse warehouse );
+
+    void Print();
+}

src/mediator/Mediator.Step0/IStore.cs

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+// Copyright (c) SharpCrafters s.r.o. See the LICENSE.md file in the root directory of this repository root for details.
+
+namespace Mediator;
+
+public interface IStore
+{
+    string Name { get; }
+
+    IReadOnlyList<Item> Items { get; }
+
+    void ReceiveItem(Item item);
+
+    void ReturnItem(Item item);
+}

src/mediator/Mediator.Step0/IWarehouse.cs

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+// Copyright (c) SharpCrafters s.r.o. See the LICENSE.md file in the root directory of this repository root for details.
+
+namespace Mediator;
+
+public interface IWarehouse
+{
+    void AddStore(IStore store );
+
+    void DistributeItem(Item item);
+
+    void AcceptReturnedItem(Item item, IStore store);
+}

src/mediator/Mediator.Step0/Item.cs

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+// Copyright (c) SharpCrafters s.r.o. See the LICENSE.md file in the root directory of this repository root for details.
+
+namespace Mediator;
+
+public class Item
+{
+    public string? Kind { get; init; }
+}

src/mediator/Mediator.Step0/LoggingService.cs

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+// Copyright (c) SharpCrafters s.r.o. See the LICENSE.md file in the root directory of this repository root for details.
+
+internal class LoggingService : ILoggingService
+{
+    public void Log(string message)
+    {
+        Console.WriteLine(message);
+    }
+}

src/mediator/Mediator.Step0/Mediator.Step0.csproj

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+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net6.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+    <RootNamespace>Mediator</RootNamespace>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="8.0.0" />
+  </ItemGroup>
+
+</Project>

src/mediator/Mediator.Step0/MetricService.cs

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+// Copyright (c) SharpCrafters s.r.o. See the LICENSE.md file in the root directory of this repository root for details.
+
+namespace Mediator;
+
+internal class MetricService : IMetricService
+{
+    private int _distributedItems;
+    private int _returnedItems;
+    private int _receivedItems;
+
+    public void ItemDistributed( IWarehouse warehouse, Item item, IStore store )
+    {
+        this._distributedItems++;
+    }
+
+    public void ItemReceived( IStore store, Item item )
+    {
+        this._receivedItems++;
+    }
+
+    public void ItemReturned( IStore store, Item item, IWarehouse warehouse )
+    {
+        this._returnedItems++;
+    }
+
+    public void Print()
+    {
+        Console.WriteLine( $"Distributed: {this._distributedItems}, Received: {this._receivedItems}, Returned: {this._returnedItems}" );
+    }
+}

src/mediator/Mediator.Step0/Program.cs

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+// Copyright (c) SharpCrafters s.r.o. See the LICENSE.md file in the root directory of this repository root for details.
+
+using Mediator;
+using Microsoft.Extensions.DependencyInjection;
+
+// Initialize services.
+var services = new ServiceCollection();
+
+services.AddSingleton<IWarehouse, Warehouse>();
+services.AddSingleton<IMetricService, MetricService>();
+services.AddSingleton<ILoggingService, LoggingService>();
+
+var serviceProvider = services.BuildServiceProvider();
+
+// Create instances of the classes.
+var w = serviceProvider.GetRequiredService<IWarehouse>();
+var s1 = ActivatorUtilities.CreateInstance<Store>( serviceProvider, "store1" );
+var s2 = ActivatorUtilities.CreateInstance<Store>( serviceProvider, "store2" );
+
+var item1 = new Item { Kind = "item1" };
+var item2 = new Item { Kind = "item2" };
+
+// Add stores.
+w.AddStore( s1 );
+w.AddStore( s2 );
+
+// Run the scenario.
+w.DistributeItem( item1 );
+w.DistributeItem( item2 );
+s1.ReturnItem( s1.Items[0] );
+
+// Print metrics.
+serviceProvider.GetRequiredService<IMetricService>().Print();

src/mediator/Mediator.Step0/Store.cs

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+// Copyright (c) SharpCrafters s.r.o. See the LICENSE.md file in the root directory of this repository root for details.
+
+namespace Mediator;
+
+internal class Store : IStore
+{
+    private readonly IWarehouse _warehouse;
+    private readonly IMetricService _metricService;
+    private readonly ILoggingService _loggingService;
+    private readonly List<Item> _items;
+
+    public string Name { get; }
+    public IReadOnlyList<Item> Items => this._items;
+
+    public Store(string name, IWarehouse warehouse, IMetricService metricService, ILoggingService loggingService )
+    {
+        this.Name = name;
+        this._warehouse = warehouse;
+        this._metricService = metricService;
+        this._loggingService = loggingService;
+        this._items = new List<Item>();
+    }
+
+    public void ReceiveItem(Item item)
+    {
+        this._items.Add( item );
+        this._metricService.ItemReceived( this, item );
+        this._loggingService.Log( $"{this.Name} received {item.Kind}." );
+    }
+
+    public void ReturnItem(Item item)
+    {
+        this._items.Remove( item );
+        this._loggingService.Log( $"{this.Name} returned {item.Kind}." );
+        this._warehouse.AcceptReturnedItem( item, this );
+    }
+}

src/mediator/Mediator.Step0/Warehouse.cs

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+// Copyright (c) SharpCrafters s.r.o. See the LICENSE.md file in the root directory of this repository root for details.
+
+namespace Mediator;
+
+internal class Warehouse : IWarehouse
+{
+    private int _nextStore;
+    private readonly List<IStore> _stores;
+    private readonly IMetricService _metricService;
+    private readonly ILoggingService _loggingService;
+
+    public Warehouse( IMetricService metricService, ILoggingService loggingService )
+    {
+        this._stores = new List<IStore>();
+        this._metricService = metricService;
+        this._loggingService = loggingService;
+    }
+
+    public void DistributeItem( Item item )
+    {
+        var store = this._stores[this._nextStore];
+        this._loggingService.Log( $"Distributed {item.Kind} to {store.Name}." );
+        store.ReceiveItem(item);
+        this._metricService.ItemDistributed( this, item, store );
+        this.ToNextStore();
+    }
+
+    public void AddStore( IStore store )
+    {
+        this._stores.Add( store );
+    }
+
+    public void AcceptReturnedItem( Item item, IStore store )
+    {
+        this._metricService.ItemReturned( store, item, this );
+
+        if ( this._stores[this._nextStore] == store)
+        {
+            this.ToNextStore();
+        }
+
+        this.DistributeItem( item );
+    }
+
+    private void ToNextStore()
+    {
+        this._nextStore = (this._nextStore + 1) % this._stores.Count;
+    }
+}

src/mediator/Mediator.Step1/DistributionMediator.cs

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+// Copyright (c) SharpCrafters s.r.o. See the LICENSE.md file in the root directory of this repository root for details.
+
+namespace Mediator;
+
+public class DistributionMediator : IDistributionMediator
+{
+    private int _nextStore;
+    private readonly Lazy<IWarehouse> _warehouse;
+    private readonly List<IStore> _stores = new();
+    private readonly IMetricService _metricService;
+    private readonly ILoggingService _loggingService;
+
+    public DistributionMediator( Lazy<IWarehouse> warehouse, IMetricService metricService, ILoggingService loggingService )
+    {
+        this._warehouse = warehouse;
+        this._metricService = metricService;
+        this._loggingService = loggingService;
+    }
+
+    public void Distribute( Item item )
+    {
+        var store = this._stores[this._nextStore];
+        this._metricService.ItemDistributed( this._warehouse.Value, item, store );
+        this._loggingService.Log( $"Distributed {item.Kind} to {store.Name}." );
+        store.ReceiveItem( item );
+        this._loggingService.Log( $"{store.Name} received {item.Kind}." );
+        this._metricService.ItemReceived( store, item );
+        this.ToNextStore();
+    }
+
+    public void AddStore( IStore store )
+    {
+        this._stores.Add( store );
+    }
+
+    public void Redistribute( Item item, IStore store )
+    {
+        if ( this._stores[this._nextStore] == store )
+        {
+            this.ToNextStore();
+        }
+
+        this.Distribute( item );
+    }
+
+    private void ToNextStore()
+    {
+        this._nextStore = (this._nextStore + 1) % this._stores.Count;
+    }
+}

src/mediator/Mediator.Step1/IDistributionMediator.cs

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+// Copyright (c) SharpCrafters s.r.o. See the LICENSE.md file in the root directory of this repository root for details.
+
+namespace Mediator;
+
+public interface IDistributionMediator
+{
+    void Distribute( Item item );
+    void AddStore( IStore store );
+    void Redistribute( Item item, IStore store );
+}

src/mediator/Mediator.Step1/ILoggingService.cs

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+// Copyright (c) SharpCrafters s.r.o. See the LICENSE.md file in the root directory of this repository root for details.
+
+public interface ILoggingService
+{
+    void Log(string message );
+}

src/mediator/Mediator.Step1/IMetricService.cs

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+// Copyright (c) SharpCrafters s.r.o. See the LICENSE.md file in the root directory of this repository root for details.
+
+namespace Mediator;
+
+public interface IMetricService
+{
+    void ItemDistributed( IWarehouse warehouse, Item item, IStore store );
+    void ItemReceived( IStore store, Item item );
+    void ItemReturned( IStore store, Item item, IWarehouse warehouse );
+
+    void Print();
+}

src/mediator/Mediator.Step1/IReturnMediator.cs

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+// Copyright (c) SharpCrafters s.r.o. See the LICENSE.md file in the root directory of this repository root for details.
+
+namespace Mediator;
+
+public interface IReturnMediator
+{
+    void ReturnItem( Item item, IStore store );
+}

src/mediator/Mediator.Step1/IStore.cs

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+// Copyright (c) SharpCrafters s.r.o. See the LICENSE.md file in the root directory of this repository root for details.
+
+namespace Mediator;
+
+public interface IStore
+{
+    string Name { get; }
+
+    IReadOnlyList<Item> Items { get; }
+
+    void ReceiveItem(Item item);
+
+    void ReturnItem(Item item);
+}

src/mediator/Mediator.Step1/IWarehouse.cs

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+// Copyright (c) SharpCrafters s.r.o. See the LICENSE.md file in the root directory of this repository root for details.
+
+namespace Mediator;
+
+public interface IWarehouse
+{
+    void DistributeItem(Item item);
+
+    void AcceptReturnedItem(Item item, IStore store);
+}

src/mediator/Mediator.Step1/Item.cs

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+// Copyright (c) SharpCrafters s.r.o. See the LICENSE.md file in the root directory of this repository root for details.
+
+namespace Mediator;
+
+public class Item
+{
+    public string? Kind { get; init; }
+}

src/mediator/Mediator.Step1/LoggingService.cs

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+// Copyright (c) SharpCrafters s.r.o. See the LICENSE.md file in the root directory of this repository root for details.
+
+internal class LoggingService : ILoggingService
+{
+    public void Log(string message)
+    {
+        Console.WriteLine(message);
+    }
+}

src/mediator/Mediator.Step1/Mediator.Step1.csproj

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+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net6.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+    <RootNamespace>Mediator</RootNamespace>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="8.0.0" />
+  </ItemGroup>
+
+</Project>