net.openhft.chronicle.core.threads

Class CleaningThread

java.lang.Object

java.lang.Thread

net.openhft.chronicle.core.threads.CleaningThread

All Implemented Interfaces:

Runnable

public class CleaningThread
extends Thread

Thread that clears its ThreadLocal values when finished.

Threads can retain references left in their ThreadLocalMap even once the ThreadLocal instance is no longer reachable. Long-lived threads may therefore accumulate stale values and leak memory. Reflection is used to walk the map and remove any entries created by CleaningThreadLocal so they are not retained after the task completes.

Nested Class Summary

Nested classes/interfaces inherited from class java.lang.Thread

Thread.State, Thread.UncaughtExceptionHandler

Field Summary

Fields inherited from class java.lang.Thread

MAX_PRIORITY, MIN_PRIORITY, NORM_PRIORITY

Constructor Summary

Constructors

Constructor and Description
CleaningThread(Runnable target) Constructs a new CleaningThread with the specified target Runnable.
CleaningThread(Runnable target, String name) Constructs a new CleaningThread with the specified target Runnable and name.
CleaningThread(Runnable target, String name, boolean inEventLoop) Constructs a new CleaningThread with the specified target Runnable, name, and inEventLoop flag.

Method Summary

Modifier and Type	Method and Description
boolean	inEventLoop() Returns the inEventLoop flag, indicating whether this thread is in an event loop.
static boolean	inEventLoop(Thread t) Checks if the given thread is an instance of CleaningThread and if it is in an event loop.
static void	performCleanup(Thread thread) Purges all CleaningThreadLocal entries for the supplied thread.
static void	performCleanup(Thread thread, CleaningThreadLocal<?> ctl) Cleans up a specific CleaningThreadLocal instance associated with the given thread.
void	run() Executes the target Runnable and then clears thread-local values.

Methods inherited from class java.lang.Thread

activeCount, checkAccess, clone, countStackFrames, currentThread, destroy, dumpStack, enumerate, getAllStackTraces, getContextClassLoader, getDefaultUncaughtExceptionHandler, getId, getName, getPriority, getStackTrace, getState, getThreadGroup, getUncaughtExceptionHandler, holdsLock, interrupt, interrupted, isAlive, isDaemon, isInterrupted, join, join, join, resume, setContextClassLoader, setDaemon, setDefaultUncaughtExceptionHandler, setName, setPriority, setUncaughtExceptionHandler, sleep, sleep, start, stop, stop, suspend, toString, yield

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

CleaningThread

public CleaningThread(Runnable target)

Constructs a new CleaningThread with the specified target Runnable.

Parameters:

target - The Runnable object to execute in the new thread.

CleaningThread

public CleaningThread(Runnable target,
                      String name)

Constructs a new CleaningThread with the specified target Runnable and name.

Parameters:

target - The Runnable object to execute in the new thread.

name - The name for the new thread.

CleaningThread

public CleaningThread(Runnable target,
                      String name,
                      boolean inEventLoop)

Constructs a new CleaningThread with the specified target Runnable, name, and inEventLoop flag.

Parameters:

target - The Runnable object to execute in the new thread.

name - The name for the new thread.

inEventLoop - The flag indicating whether the thread is in an event loop.

Method Detail

performCleanup

public static void performCleanup(Thread thread)

Purges all CleaningThreadLocal entries for the supplied thread.

Thread-local maps hold strong references to their values until removed. If a task discards its CleaningThreadLocal but the thread lives on, those values leak. This method walks the hidden map via reflection and removes the entries we created. If garbage collection has cleared a weak key the value cannot be located and remains until the table is resized.

Parameters:

thread - the thread whose CleaningThreadLocal instances are to be cleared

performCleanup

public static void performCleanup(Thread thread,
                                  CleaningThreadLocal<?> ctl)

Cleans up a specific CleaningThreadLocal instance associated with the given thread.

Parameters:

thread - The thread whose specific CleaningThreadLocal instance is to be cleaned up.

ctl - The specific CleaningThreadLocal instance to clean up. If null, cleans all.

inEventLoop

public static boolean inEventLoop(Thread t)

Checks if the given thread is an instance of CleaningThread and if it is in an event loop.

Parameters:

t - The thread to check.

Returns:

true if the thread is an instance of CleaningThread and in an event loop, false otherwise.

run

public void run()

Executes the target Runnable and then clears thread-local values.

If an event loop pinned this thread to a single CPU, the affinity is reset to AffinityLock.BASE_AFFINITY before user code runs so the binding does not leak once the loop has finished.

Sub-classes overriding this method should call super.run() to retain the affinity reset and cleanup behaviour.

Specified by:

run in interface Runnable

Overrides:

run in class Thread

inEventLoop

public boolean inEventLoop()

Returns the inEventLoop flag, indicating whether this thread is in an event loop.

Returns:

true if this thread is in an event loop, false otherwise.