A generic, concurrent, portable and flexible Object Pool for .NET. It is completely based on the Code Project article of Ofir Makmal (http://goo.gl/4qig6T). Library is production ready and it is successfully working in real life systems. Original source code has been modified, in order to introduce a Parameterized Object Pool, already drafted by Ofir Makmal in the comments of the article. Moreover, a few unit tests have been added, in order to improve code reliability, and a lot of other small changes have also been applied. Of course, all modified source code is freely available at the project URL of this package. Many thanks to Ofir Makmal for his great work.
A generic, concurrent, portable and flexible Object Pool for .NET, completely based on the Code Project article of Ofir Makmal.
Library is feature complete and no further development is planned on this project, except for routine maintenance and bug fixes.
Original source code has been modified, in order to introduce:
Microsoft.IO.RecyclableMemoryStream library
from Microsoft. It eliminates Large Object Heap allocations, which this library does not do.Moreover, a few unit tests have been added, in order to improve code reliability, and a lot of other small changes have also been applied.
Of course, all modified source code is freely available in this repository.
Many thanks to Ofir Makmal for his great work.
NuGet package CodeProject.ObjectPool is available for download:
dotnet add package CodeProject.ObjectPoolAn adapter for Microsoft.Extensions.ObjectPool is also available on NuGet:
dotnet add package CodeProject.ObjectPool.MicrosoftExtensionsAdapterQuick and dirty example:
/// <summary>
/// Example usages of ObjectPool.
/// </summary>
internal static class Program
{
/// <summary>
/// Example usages of ObjectPool.
/// </summary>
private static void Main()
{
// Creating a pool with a maximum size of 25, using custom Factory method to create and
// instance of ExpensiveResource.
var pool = new ObjectPool<ExpensiveResource>(25, () => new ExpensiveResource(/* resource specific initialization */));
using (var resource = pool.GetObject())
{
// Using the resource...
resource.DoStuff();
} // Exiting the using scope will return the object back to the pool.
// Creating a pool with wrapper object for managing external resources, that is, classes
// which cannot inherit from PooledObject.
var newPool = new ObjectPool<PooledObjectWrapper<ExternalExpensiveResource>>(() =>
new PooledObjectWrapper<ExternalExpensiveResource>(CreateNewResource())
{
OnReleaseResources = ExternalResourceReleaseResource,
OnResetState = ExternalResourceResetState
});
using (var wrapper = newPool.GetObject())
{
// wrapper.InternalResource contains the object that you pooled.
wrapper.InternalResource.DoOtherStuff();
} // Exiting the using scope will return the object back to the pool.
// Creates a pool where objects which have not been used for over 2 seconds will be
// cleaned up by a dedicated thread.
var timedPool = new TimedObjectPool<ExpensiveResource>(TimeSpan.FromSeconds(2));
using (var resource = timedPool.GetObject())
{
// Using the resource...
resource.DoStuff();
} // Exiting the using scope will return the object back to the pool and record last usage.
Console.WriteLine($"Timed pool size after 0 seconds: {timedPool.ObjectsInPoolCount}"); // Should be 1
Thread.Sleep(TimeSpan.FromSeconds(4));
Console.WriteLine($"Timed pool size after 4 seconds: {timedPool.ObjectsInPoolCount}"); // Should be 0
// Adapts a timed pool to Microsoft Extensions abstraction.
var mPool = ObjectPoolAdapter.CreateForPooledObject(timedPool);
// Sample usage of Microsoft pool.
var mResource = mPool.Get();
Debug.Assert(mResource is ExpensiveResource);
mPool.Return(mResource);
// Adapts a new pool to Microsoft Extensions abstraction. This example shows how to adapt
// when object type does not extend PooledObject.
var mPool2 = ObjectPoolAdapter.Create(new ObjectPool<PooledObjectWrapper<MemoryStream>>(
() => PooledObjectWrapper.Create(new MemoryStream())));
// Sample usage of second Microsoft pool.
var mResource2 = mPool2.Get();
Debug.Assert(mResource2 is MemoryStream);
mPool2.Return(mResource2);
Console.Read();
}
private static ExternalExpensiveResource CreateNewResource()
{
return new ExternalExpensiveResource();
}
public static void ExternalResourceResetState(ExternalExpensiveResource resource)
{
// External Resource reset state code.
}
public static void ExternalResourceReleaseResource(ExternalExpensiveResource resource)
{
// External Resource release code.
}
}
internal sealed class ExpensiveResource : PooledObject
{
public ExpensiveResource()
{
OnReleaseResources = () =>
{
// Called if the resource needs to be manually cleaned before the memory is reclaimed.
};
OnResetState = () =>
{
// Called if the resource needs resetting before it is getting back into the pool.
};
}
public void DoStuff()
{
// Do some work here, for example.
}
}
internal sealed class ExternalExpensiveResource
{
public void DoOtherStuff()
{
// Do some work here, for example.
}
}Starting from v4, Object Pool supports async pooled object initialization. Therefore, objects can be retrieved in two ways:
obj = pool.GetObject();
obj = await pool.GetObjectAsync();Those methods depend on the factory method specified during pool initialization. Because making async factories "sync" is usually a problem, which can lead to deadlocks, we have the following situation:
| Factory type | GetObject | GeObjectAsync |
|---|---|---|
| Not specified | OK | OK, uses a result task |
| Sync | OK | OK, uses a result task |
| Async | KO, throws an exception | OK |
So, to sum it up:
PRs accepted.
Small note: If editing the README, please conform to the standard-readme specification.
MIT © 2013-2021 Alessio Parma