Netty5/Common 5.0.0.Alpha5 · io.netty5.util.concurrent.FastThreadLocal

A special variant of ThreadLocal that yields higher access performance when accessed from a FastThreadLocalThread.

Internally, a FastThreadLocal uses a constant index in an array, instead of using hash code and hash table, to look for a variable. Although seemingly very subtle, it yields slight performance advantage over using a hash table, and it is useful when accessed frequently.

To take advantage of this thread-local variable, your thread must be a FastThreadLocalThread or its subtype. By default, all threads created by DefaultThreadFactory are FastThreadLocalThread due to this reason.

Note that the fast path is only possible on threads that extend FastThreadLocalThread, because it requires a special field to store the necessary state. An access by any other kind of thread falls back to a regular ThreadLocal.

Field Summary

Modifier and Type	Field and Description
private final int	index
private static final int	variablesToRemoveIndex

Constructor Summary

Access	Constructor and Description
public	FastThreadLocal()

Method Summary

Modifier and Type	Method and Description
private static void	addToVariablesToRemove(InternalThreadLocalMap threadLocalMap, FastThreadLocal<?> variable)
public static void	destroy() Destroys the data structure that keeps all `FastThreadLocal` variables accessed from non-`FastThreadLocalThread`s.
public final V	get() Returns the current value for the current thread
public final V	getIfExists() Returns the current value for the current thread if it exists, `null` otherwise.
private V	initialize(InternalThreadLocalMap threadLocalMap)
protected V	initialValue() Returns the initial value for this thread-local variable.
public final boolean	isSet() Returns `true` if and only if this thread-local variable is set.
private boolean	isSet(InternalThreadLocalMap threadLocalMap) Returns `true` if and only if this thread-local variable is set.
protected void	onRemoval(V value) Invoked when this thread local variable is removed by `remove()`.
public final void	remove() Sets the value to uninitialized for the specified thread local map.
private void	remove(InternalThreadLocalMap threadLocalMap) Sets the value to uninitialized for the specified thread local map.
public static void	removeAll() Removes all `FastThreadLocal` variables bound to the current thread.
private static void	removeFromVariablesToRemove(InternalThreadLocalMap threadLocalMap, FastThreadLocal<?> variable)
public final void	set(V value) Set the value for the current thread.
private void	set(InternalThreadLocalMap threadLocalMap, V value) Set the value for the specified thread local map.
private void	setKnownNotUnset(InternalThreadLocalMap threadLocalMap, V value)
public static int	size() Returns the number of thread local variables bound to the current thread.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

index	back to summary
private final int index

variablesToRemoveIndex	back to summary
private static final int variablesToRemoveIndex

Constructor Detail

FastThreadLocal	back to summary
public FastThreadLocal()

Method Detail

addToVariablesToRemove	back to summary
private static void addToVariablesToRemove(InternalThreadLocalMap threadLocalMap, FastThreadLocal<?> variable) Annotations @SuppressWarnings:unchecked

destroy	back to summary
public static void destroy() Destroys the data structure that keeps all `FastThreadLocal` variables accessed from non-`FastThreadLocalThread`s. This operation is useful when you are in a container environment, and you do not want to leave the thread local variables in the threads you do not manage. Call this method when your application is being unloaded from the container.

get	back to summary
public final V get() Returns the current value for the current thread Annotations @SuppressWarnings:unchecked

get

back to summary

public final V get()

Returns the current value for the current thread

Annotations

@SuppressWarnings:unchecked

getIfExists back to summary

getIfExists	back to summary
public final V getIfExists() Returns the current value for the current thread if it exists, `null` otherwise. Annotations @SuppressWarnings:unchecked

public final V getIfExists()

Returns the current value for the current thread if it exists, null otherwise.

Annotations

@SuppressWarnings:unchecked

initialize	back to summary
private V initialize(InternalThreadLocalMap threadLocalMap)

initialValue	back to summary
protected V initialValue() throws Exception Returns the initial value for this thread-local variable.

isSet	back to summary
public final boolean isSet() Returns `true` if and only if this thread-local variable is set.

isSet	back to summary
private boolean isSet(InternalThreadLocalMap threadLocalMap) Returns `true` if and only if this thread-local variable is set. The specified thread local map must be for the current thread.

onRemoval	back to summary
protected void onRemoval(V value) throws Exception Invoked when this thread local variable is removed by `remove()`. Be aware that `remove()` is not guaranteed to be called when the `Thread` completes which means you can not depend on this for cleanup of the resources in the case of `Thread` completion.

remove	back to summary
public final void remove() Sets the value to uninitialized for the specified thread local map. After this, any subsequent call to get() will trigger a new call to initialValue().

remove	back to summary
private void remove(InternalThreadLocalMap threadLocalMap) Sets the value to uninitialized for the specified thread local map. After this, any subsequent call to get() will trigger a new call to initialValue(). The specified thread local map must be for the current thread. Annotations @SuppressWarnings:unchecked

remove

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private void remove(InternalThreadLocalMap threadLocalMap)

Sets the value to uninitialized for the specified thread local map. After this, any subsequent call to get() will trigger a new call to initialValue(). The specified thread local map must be for the current thread.

Annotations

@SuppressWarnings:unchecked

removeAll	back to summary
public static void removeAll() Removes all `FastThreadLocal` variables bound to the current thread. This operation is useful when you are in a container environment, and you don't want to leave the thread local variables in the threads you do not manage.

removeFromVariablesToRemove	back to summary
private static void removeFromVariablesToRemove(InternalThreadLocalMap threadLocalMap, FastThreadLocal<?> variable)

set	back to summary
public final void set(V value) Set the value for the current thread.

set	back to summary
private void set(InternalThreadLocalMap threadLocalMap, V value) Set the value for the specified thread local map. The specified thread local map must be for the current thread.

setKnownNotUnset	back to summary
private void setKnownNotUnset(InternalThreadLocalMap threadLocalMap, V value) See Also `InternalThreadLocalMap#setIndexedVariable(int, Object).`

size	back to summary
public static int size() Returns the number of thread local variables bound to the current thread.

public Class FastThreadLocal<V>

Field Summary

Constructor Summary

Method Summary

Field Detail

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Method Detail