Class DisposableThreadLocal<T>

.NET's built-in System.Threading.ThreadLocal`1 has a serious flaw: internally, it creates an array with an internal lattice structure which in turn causes the garbage collector to cause long blocking pauses when tearing the structure down. See https://ayende.com/blog/189761-A/production-postmortem-the-slow-slowdown-of-large-systems for a more detailed explanation.

This is a completely different problem than in Java which the ClosableThreadLocal<T> class is meant to solve, so DisposableThreadLocal<T> is specific to Lucene.NET and can be used as a direct replacement for ClosableThreadLocal<T>.

This class works around the issue by using an alternative approach than using System.Threading.ThreadLocal`1. It keeps track of each thread's local and global state in order to later optimize garbage collection. A complete explanation can be found at https://ayende.com/blog/189793-A/the-design-and-implementation-of-a-better-threadlocal-t.

Note

This API is for internal purposes only and might change in incompatible ways in the next release.

Inheritance

System.Object

DisposableThreadLocal<T>

Implements

System.IDisposable

Inherited Members

System.Object.Equals(System.Object)

System.Object.Equals(System.Object, System.Object)

System.Object.GetHashCode()

System.Object.GetType()

System.Object.MemberwiseClone()

System.Object.ReferenceEquals(System.Object, System.Object)

System.Object.ToString()

Namespace: Lucene.Net.Util

Assembly: Lucene.Net.dll

Syntax

public sealed class DisposableThreadLocal<T> : IDisposable

Type Parameters

Name	Description
T	Specifies the type of data stored per-thread.

Constructors

DisposableThreadLocal()

Initializes the DisposableThreadLocal<T> instance.

Declaration

public DisposableThreadLocal()

Remarks

The default value of T is used to initialize the instance when Value is accessed for the first time.

DisposableThreadLocal(Func<T>)

Initializes the DisposableThreadLocal<T> instance with the specified valueFactory function.

Declaration

public DisposableThreadLocal(Func<T> valueFactory)

Parameters

Type	Name	Description
System.Func<T>	valueFactory	The System.Func<T, TResult> invoked to produce a lazily-initialized value when an attempt is made to retrieve Value without it having been previously initialized.

Exceptions

Type	Condition
System.ArgumentNullException	valueFactory is null.

Properties

IsValueCreated

Gets whether Value is initialized on the current thread.

Declaration

public bool IsValueCreated { get; }

Property Value

Type	Description
System.Boolean

Exceptions

Type	Condition
System.ObjectDisposedException	The DisposableThreadLocal<T> instance has been disposed.

Value

Gets or sets the value of this instance for the current thread.

Declaration

public T Value { get; set; }

Property Value

Type	Description
T

Remarks

If this instance was not previously initialized for the current thread, accessing Value will attempt to initialize it. If an initialization function was supplied during the construction, that initialization will happen by invoking the function to retrieve the initial value for Value. Otherwise, the default value of T will be used.

Exceptions

Type	Condition
System.ObjectDisposedException	The DisposableThreadLocal<T> instance has been disposed.

Values

Gets a collection for all of the values currently stored by all of the threads that have accessed this instance.

Declaration

public ICollection<T> Values { get; }

Property Value

Type	Description
System.Collections.Generic.ICollection<T>

Exceptions

Type	Condition
System.ObjectDisposedException	The DisposableThreadLocal<T> instance has been disposed.

Methods

Dispose()

Releases the resources used by this DisposableThreadLocal<T> instance.

Declaration

public void Dispose()

Get()

Declaration

[Obsolete("Use Value instead. This method will be removed in 4.8.0 release candidate.")]
public T Get()

Returns

Type	Description
T

Set(T)

Declaration

[Obsolete("Use Value instead. This method will be removed in 4.8.0 release candidate.")]
public void Set(T value)

Parameters

Type	Name	Description
T	value

Implements

System.IDisposable