Add command pattern

BehavioralPatterns.sln

@@ -14,6 +14,8 @@ Project("{8BB2217D-0F2D-49D1-97BC-3654ED321F3B}") = "BehavioralPatterns", "src\B
 EndProject
 Project("{8BB2217D-0F2D-49D1-97BC-3654ED321F3B}") = "ChainOfResponssibility", "src\ChainOfResponssibility\ChainOfResponssibility.xproj", "{89536824-683F-4351-8789-406D7BDD922D}"
 EndProject
+Project("{8BB2217D-0F2D-49D1-97BC-3654ED321F3B}") = "CommandPattern", "src\CommandPattern\CommandPattern.xproj", "{454B2A43-8251-4667-8DE3-67E489908DB9}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -28,6 +30,10 @@ Global
 		{89536824-683F-4351-8789-406D7BDD922D}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{89536824-683F-4351-8789-406D7BDD922D}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{89536824-683F-4351-8789-406D7BDD922D}.Release|Any CPU.Build.0 = Release|Any CPU
+		{454B2A43-8251-4667-8DE3-67E489908DB9}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{454B2A43-8251-4667-8DE3-67E489908DB9}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{454B2A43-8251-4667-8DE3-67E489908DB9}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{454B2A43-8251-4667-8DE3-67E489908DB9}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -35,5 +41,6 @@ Global
 	GlobalSection(NestedProjects) = preSolution
 		{E3092EE0-1282-4AB4-9FA2-0338348D8FD1} = {3820200F-354C-41E6-8F34-B301F5D621C2}
 		{89536824-683F-4351-8789-406D7BDD922D} = {3820200F-354C-41E6-8F34-B301F5D621C2}
+		{454B2A43-8251-4667-8DE3-67E489908DB9} = {3820200F-354C-41E6-8F34-B301F5D621C2}
 	EndGlobalSection
 EndGlobal

src/BehavioralPatterns/Program.cs

@@ -1,5 +1,6 @@
 using ChainOfResponssibility;
 using ChainOfResponssibility.PurchaseExample;
+using CommandPattern;
 using System;
 using System.Collections.Generic;
 using System.Diagnostics;
@@ -16,6 +17,8 @@ namespace BehavioralPatterns
             //This is usefull when you have a request and you don't know who should process it
             ChainOfResponsibillityExamples.Run();
             Console.ReadKey();
+            CommandPatternExamples.Run();
+            Console.ReadKey();
         }
     }
 }

src/BehavioralPatterns/project.json

@@ -6,6 +6,7 @@
 
   "dependencies": {
     "ChainOfResponssibility": "1.0.0-*",
+    "CommandPattern": "1.0.0-*",
     "Microsoft.NETCore.App": {
       "type": "platform",
       "version": "1.0.0-rc2-3002702"

src/CommandPattern/CommandPattern.xproj

@@ -0,0 +1,21 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="14.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <PropertyGroup>
+    <VisualStudioVersion Condition="'$(VisualStudioVersion)' == ''">14.0</VisualStudioVersion>
+    <VSToolsPath Condition="'$(VSToolsPath)' == ''">$(MSBuildExtensionsPath32)\Microsoft\VisualStudio\v$(VisualStudioVersion)</VSToolsPath>
+  </PropertyGroup>
+
+  <Import Project="$(VSToolsPath)\DotNet\Microsoft.DotNet.Props" Condition="'$(VSToolsPath)' != ''" />
+  <PropertyGroup Label="Globals">
+    <ProjectGuid>454b2a43-8251-4667-8de3-67e489908db9</ProjectGuid>
+    <RootNamespace>CommandPattern</RootNamespace>
+    <BaseIntermediateOutputPath Condition="'$(BaseIntermediateOutputPath)'=='' ">.\obj</BaseIntermediateOutputPath>
+    <OutputPath Condition="'$(OutputPath)'=='' ">.\bin\</OutputPath>
+    <TargetFrameworkVersion>v4.6.1</TargetFrameworkVersion>
+  </PropertyGroup>
+
+  <PropertyGroup>
+    <SchemaVersion>2.0</SchemaVersion>
+  </PropertyGroup>
+  <Import Project="$(VSToolsPath)\DotNet\Microsoft.DotNet.targets" Condition="'$(VSToolsPath)' != ''" />
+</Project>

src/CommandPattern/CommandPatternExamples.cs

@@ -0,0 +1,45 @@
+using CommandPattern.StocksExample;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+
+namespace CommandPattern
+{
+    public class CommandPatternExamples
+    {
+        public static void Run()
+        {
+            Console.WriteLine(GetPatternDescription());
+            GoToNextStep();
+
+            StockExampleRunner stockExampleRunner = new StockExampleRunner();
+            Console.WriteLine(stockExampleRunner.GetDescriptionOfExample());
+            GoToNextStep();
+            stockExampleRunner.Run();
+            stockExampleRunner.Run();
+            stockExampleRunner.Run();
+            stockExampleRunner.Run();
+        }
+
+        private static void GoToNextStep()
+        {            
+            Console.ReadKey();
+            Console.Clear();
+        }
+
+        public static string GetPatternDescription()
+        {
+            return @"
+command pattern is a behavioral design pattern in which an object is used to encapsulate 
+all information needed to perform an action or trigger an event at a later time
+Uses:
+1. Macro recording: f all user actions are represented by command objects, a program can record a 
+sequence of actions simply by keeping a list of the command objects as they are executed.
+2. Undo
+3. GUI buttons and menu items
+4. Parallel processing
+5. Transactional behavior ";
+        }
+    }
+}

src/CommandPattern/Program.cs

@@ -0,0 +1,14 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+
+namespace CommandPattern
+{
+    public class Program
+    {
+        public static void Main(string[] args)
+        {
+        }
+    }
+}

src/CommandPattern/Properties/AssemblyInfo.cs

@@ -0,0 +1,19 @@
+using System.Reflection;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+
+// General Information about an assembly is controlled through the following
+// set of attributes. Change these attribute values to modify the information
+// associated with an assembly.
+[assembly: AssemblyConfiguration("")]
+[assembly: AssemblyCompany("Hewlett-Packard Company")]
+[assembly: AssemblyProduct("CommandPattern")]
+[assembly: AssemblyTrademark("")]
+
+// Setting ComVisible to false makes the types in this assembly not visible
+// to COM components.  If you need to access a type in this assembly from
+// COM, set the ComVisible attribute to true on that type.
+[assembly: ComVisible(false)]
+
+// The following GUID is for the ID of the typelib if this project is exposed to COM
+[assembly: Guid("454b2a43-8251-4667-8de3-67e489908db9")]

src/CommandPattern/StocksExample/Agent.cs

@@ -0,0 +1,47 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+
+namespace CommandPattern.StocksExample
+{
+    /// <summary>
+    /// Invoker. The invoker will invoke the command
+    /// </summary>
+    public class Agent
+    {
+        Stack<Order> ordersNotExecuted;
+        FixedSizedQueue<Order> ordersPlaced;
+        StockSchedule stockSchedule;
+
+        public Agent(StockSchedule stockSchedule)
+        {
+            ordersNotExecuted = new Stack<Order>();
+            ordersPlaced = new FixedSizedQueue<Order>(10);
+            this.stockSchedule = stockSchedule;
+            stockSchedule.StockExchangedOpened += StockSchedule_StockExchangedOpened;
+        }
+
+        private void StockSchedule_StockExchangedOpened(object sender, EventArgs e)
+        {
+            while (ordersNotExecuted.Any())
+            {
+                PlaceOrder(ordersNotExecuted.Pop());
+            }
+        }
+
+        public void PlaceOrder(Order order)
+        {
+            if(stockSchedule.IsStockOpen())
+            {
+                order.Execute();
+                ordersPlaced.Enqueue(order);
+            }
+            else
+            {
+                Console.WriteLine("Market is not opened, so the order was saved for later");
+                ordersNotExecuted.Push(order);
+            }
+        }        
+    }
+}

src/CommandPattern/StocksExample/Commands/BuyStockOrder.cs

@@ -0,0 +1,24 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+
+namespace CommandPattern.StocksExample.Commands
+{
+    //Concrete Command
+    public class BuyStockOrder : Order
+    {
+        StocksAPI stocksAPI;
+        Stock stock;
+        public BuyStockOrder(StocksAPI stocksAPI, Stock stock)
+        {
+            this.stocksAPI = stocksAPI;
+            this.stock = stock;
+        }
+
+        public void Execute()
+        {
+            stocksAPI.Buy(stock);
+        }
+    }
+}

src/CommandPattern/StocksExample/Commands/SellStockOrder.cs

@@ -0,0 +1,23 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+
+namespace CommandPattern.StocksExample.Commands
+{
+    public class SellStockOrder : Order
+    {
+        StocksAPI stocksAPI;
+        Stock stock;
+        public SellStockOrder(StocksAPI stocksAPI, Stock stock)
+        {
+            this.stocksAPI = stocksAPI;
+            this.stock = stock;
+        }
+
+        public void Execute()
+        {
+            stocksAPI.Sell(stock);
+        }
+    }
+}

src/CommandPattern/StocksExample/FixedSizedQueue.cs

@@ -0,0 +1,29 @@
+using System.Collections.Concurrent;
+
+namespace CommandPattern.StocksExample
+{
+    public class FixedSizedQueue<T> : ConcurrentQueue<T>
+    {
+        private readonly object syncObject = new object();
+
+        public int Size { get; private set; }
+
+        public FixedSizedQueue(int size)
+        {
+            Size = size;
+        }
+
+        public new void Enqueue(T obj)
+        {
+            base.Enqueue(obj);
+            lock (syncObject)
+            {
+                while (Count > Size)
+                {
+                    T outObj;
+                    TryDequeue(out outObj);
+                }
+            }
+        }
+    }
+}

src/CommandPattern/StocksExample/Order.cs

@@ -0,0 +1,15 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+
+namespace CommandPattern.StocksExample
+{
+    /// <summary>
+    /// Command interface
+    /// </summary>
+    public interface Order
+    {
+        void Execute();
+    }
+}

src/CommandPattern/StocksExample/Stock.cs

@@ -0,0 +1,8 @@
+namespace CommandPattern.StocksExample
+{
+    public class Stock
+    {
+        public string Name { get; set; }
+        public int Quantity { get; set; }
+    }
+}

src/CommandPattern/StocksExample/StockExampleRunner.cs

@@ -0,0 +1,30 @@
+using CommandPattern.StocksExample.Commands;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+
+namespace CommandPattern.StocksExample
+{
+    public class StockExampleRunner
+    {
+        public void Run()
+        {
+            StocksAPI stocksAPI = new StocksAPI();
+            Agent agent = new Agent(new StockSchedule());
+
+            Stock stock = new Stock { Name = "AAPL", Quantity = 20 };
+
+            agent.PlaceOrder(new BuyStockOrder(stocksAPI, stock));
+            agent.PlaceOrder(new SellStockOrder(stocksAPI, stock));
+        }
+
+        public string GetDescriptionOfExample()
+        {
+            return @"
+Buy or sell a stock on the market. 
+If the market is closed save the orders for when the market opens again.
+When the market opens place all the orders.";
+        }
+    }
+}

src/CommandPattern/StocksExample/StockSchedule.cs

@@ -0,0 +1,50 @@
+using System;
+using System.Threading;
+
+namespace CommandPattern.StocksExample
+{
+    public class StockSchedule
+    {
+        TimeSpan openingTime;
+        public StockSchedule()
+        {
+            CheckForOpeningOfStockExchange();
+            openingTime = new TimeSpan(9, 0, 0);
+        }        
+
+        public event EventHandler StockExchangedOpened;
+        
+        public bool IsStockOpen()
+        {
+            return new Random().NextDouble() > 0.5;
+        }
+
+        private void OnStockExchangedOpened(object state)
+        {
+            StockExchangedOpened?.Invoke(this, null);
+            Thread.Sleep(1);
+            CheckForOpeningOfStockExchange();
+
+        }
+
+        private void CheckForOpeningOfStockExchange()
+        {
+            var t = new Timer(new TimerCallback(OnStockExchangedOpened), null, Timeout.Infinite, Timeout.Infinite);
+
+            // Figure how much time until opening market
+            DateTime now = DateTime.Now;
+            DateTime openingTime = DateTime.Today.Add(this.openingTime);
+
+            // If it's already past opening time, wait until opening time tomorrow    
+            if (now > openingTime)
+            {
+                openingTime = openingTime.AddDays(1.0);
+            }
+
+            int msUntilOpeningHour = (int)((openingTime - now).TotalMilliseconds);
+
+            // Set the timer to elapse only once, at opening time.
+            t.Change(msUntilOpeningHour, Timeout.Infinite);
+        }
+    }
+}

src/CommandPattern/StocksExample/StocksAPI.cs

@@ -0,0 +1,20 @@
+using System;
+
+namespace CommandPattern.StocksExample
+{
+    /// <summary>
+    /// Receiver of the command. Concrete command is executing code from this class
+    /// </summary>
+    public class StocksAPI
+    {
+        public void Buy(Stock stock)
+        {
+            Console.WriteLine("Stock [ Name: {0}, Quantity: {1} bought", stock.Name, stock.Quantity);
+        }
+
+        public void Sell(Stock stock)
+        {
+            Console.WriteLine("Stock [ Name: {0}, Quantity: {1} sold", stock.Name, stock.Quantity);
+        }
+    }
+}

src/CommandPattern/project.json

@@ -0,0 +1,19 @@
+{
+  "version": "1.0.0-*",
+  "buildOptions": {
+    "emitEntryPoint": true
+  },
+
+  "dependencies": {
+    "Microsoft.NETCore.App": {
+      "type": "platform",
+      "version": "1.0.0-rc2-3002702"
+    }
+  },
+
+  "frameworks": {
+    "netcoreapp1.0": {
+      "imports": "dnxcore50"
+    }
+  }
+}