Added ObjectPool

Author: linkdotnet

ObjectPool/ObjectPool.cs

@@ -0,0 +1,21 @@
+using System.Collections.Concurrent;
+
+public class ObjectPool<T>
+{
+    private readonly ConcurrentBag<T> _objects;
+    private readonly Func<T> _objectGenerator;
+
+    /// <summary>
+    /// Initializes the ObjectPool.
+    /// </summary>
+    /// <param name="objectGenerator">We need a generator function to create an object if our pool is empty.</param>
+    public ObjectPool(Func<T> objectGenerator)
+    {
+        _objectGenerator = objectGenerator ?? throw new ArgumentNullException(nameof(objectGenerator));
+        _objects = new ConcurrentBag<T>();
+    }
+    
+    public T Rent() => _objects.TryTake(out T item) ? item : _objectGenerator();
+
+    public void Return(T item) => _objects.Add(item);
+}

ObjectPool/ObjectPool.csproj

@@ -0,0 +1,14 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <OutputType>Exe</OutputType>
+        <TargetFramework>net6.0</TargetFramework>
+        <ImplicitUsings>enable</ImplicitUsings>
+        <Nullable>enable</Nullable>
+    </PropertyGroup>
+
+    <ItemGroup>
+      <PackageReference Include="BenchmarkDotNet" Version="0.13.1" />
+    </ItemGroup>
+
+</Project>

ObjectPool/ObjectPool.sln

@@ -0,0 +1,16 @@
+
+Microsoft Visual Studio Solution File, Format Version 12.00
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ObjectPool", "ObjectPool.csproj", "{0954C875-44A3-415E-844D-21593DB67D41}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{0954C875-44A3-415E-844D-21593DB67D41}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{0954C875-44A3-415E-844D-21593DB67D41}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{0954C875-44A3-415E-844D-21593DB67D41}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{0954C875-44A3-415E-844D-21593DB67D41}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+EndGlobal

ObjectPool/Program.cs

@@ -0,0 +1,51 @@
+using BenchmarkDotNet.Attributes;
+using BenchmarkDotNet.Running;
+
+BenchmarkRunner.Run<PoolBenchmark>();
+
+[MemoryDiagnoser]
+public class PoolBenchmark
+{
+    private const int LoopCount = 10;
+
+    [Benchmark(Baseline = true)]
+    public int CreateNewObjects()
+    {
+        var sum = 0;
+        for (var i = 0; i < LoopCount; i++)
+        {
+            var obj = new MyHeavyClass();
+            sum += obj.Length;
+        }
+        
+        return sum;
+    }
+
+    [Benchmark]
+    public int ObjectPool()
+    {
+        var  pool = new ObjectPool<MyHeavyClass>(() => new MyHeavyClass());
+        var sum = 0;
+        for (var i = 0; i < LoopCount; i++)
+        {
+            var obj = pool.Rent();
+            sum += obj.Length;
+            pool.Return(obj);
+        }
+        
+        return sum;
+    }
+}
+
+public class MyHeavyClass
+{
+    private readonly double[] _someArray;
+
+    public MyHeavyClass()
+    {
+        _someArray = new double[5000];
+        Array.Fill(_someArray, 10);
+    }
+
+    public int Length => _someArray.Length;
+}

ObjectPool/README.md

@@ -0,0 +1,7 @@
+# ObjectPool - Rent and return some instances
+
+Just imagine a car pool: There is a dealer which bought the car and lent's it to you. After a while you will return this car where you got it from. Much like that works an **ObjectPool** in C#. You can rent an expensive object from the pool and when you are done with it, you just return it. Sounds beautiful, doesn't it?
+
+Let's explore the advantages and disadvantages of a **ObjectPool**s and how they work.
+
+Found [here](https://steven-giesel.com/blogPost/389e5983-9726-448d-a693-1f7379165c4d)

README.md

@@ -4,6 +4,7 @@ Contains all of my examples from various blog posts. You can find a comprehensiv
 
 | BlogPost                                                                                 | Publish Date |
 | ---------------------------------------------------------------------------------------- | ------------ |
+| [ObjectPool - Rent and return some instances](ObjectPool/)                               | 02.06.2022   |
 | [Blazor with an RSS Feed](BlazorRSSFeed/)                                                | 30.05.2022   |
 | [How to unit test a RavenDB](RavenDBUnitTest/)                                           | 25.05.2022   |
 | [Blazor with CancellationToken support](BlazorCancellation/)                             | 18.05.2022   |