reset Thread Local - Java java.lang

Java examples for java.lang:ThreadLocal

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Description

reset Thread Local

Demo Code


//package com.java2s;

import java.lang.reflect.Array;
import java.lang.reflect.Field;

public class Main {
    public static void main(String[] argv) throws Exception {
        Object lock = "java2s.com";
        resetThreadLocal(lock);// w  w w . j a  v  a2s.  c om
    }

    static private Field threadLocalsField;
    static private Field tableField;
    static private Field referentField;

    static final public void resetThreadLocal(Object lock) {
        synchronized (lock) {
            // Get a reference to the thread locals table of the current thread
            try {
                Thread thread = Thread.currentThread();

                threadLocalsField.setAccessible(true);
                Object threadLocalTable = threadLocalsField.get(thread);

                // Get a reference to the array holding the thread local variables inside the
                // ThreadLocalMap of the current thread

                tableField.setAccessible(true);
                Object table = tableField.get(threadLocalTable);

                // The key to the ThreadLocalMap is a WeakReference object. The referent field of this object
                // is a reference to the actual ThreadLocal variable
                referentField.setAccessible(true);

                for (int i = 0; i < Array.getLength(table); i++) {
                    // Each entry in the table array of ThreadLocalMap is an Entry object
                    // representing the thread local reference and its value
                    Object entry = Array.get(table, i);
                    if (entry != null) {
                        // Get a reference to the thread local object and remove it from the table
                        ThreadLocal<?> threadLocal = (ThreadLocal<?>) referentField
                                .get(entry);
                        threadLocal.remove();
                    }
                }
            } catch (Exception e) {
            } //noop
            finally {
                try {
                    if (referentField != null)
                        referentField.setAccessible(false);
                    if (tableField != null)
                        tableField.setAccessible(false);
                    if (threadLocalsField != null)
                        threadLocalsField.setAccessible(false);
                } catch (Throwable e) {
                    // TODO: log error
                }
            }
        }
    }
}

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