TransmittableThreadLocal正确使用方式
/**
* Capture all {@link TransmittableThreadLocal} values in current thread.
*
* @return the captured {@link TransmittableThreadLocal} values
* @since 2.3.0
*/
@Nonnull
public static Object capture() {
Map<TransmittableThreadLocal<?>, Object> captured = new HashMap<TransmittableThreadLocal<?>, Object>();
for (TransmittableThreadLocal<?> threadLocal : holder.get().keySet()) {
captured.put(threadLocal, threadLocal.copyValue());
}
return captured;
}
/**
* Replay the captured {@link TransmittableThreadLocal} values from {@link #capture()},
* and return the backup {@link TransmittableThreadLocal} values in current thread before replay.
*
* @param captured captured {@link TransmittableThreadLocal} values from other thread from {@link #capture()}
* @return the backup {@link TransmittableThreadLocal} values before replay
* @see #capture()
* @since 2.3.0
*/
@Nonnull
public static Object replay(@Nonnull Object captured) {
@SuppressWarnings("unchecked")
Map<TransmittableThreadLocal<?>, Object> capturedMap = (Map<TransmittableThreadLocal<?>, Object>) captured;
Map<TransmittableThreadLocal<?>, Object> backup = new HashMap<TransmittableThreadLocal<?>, Object>();
for (Iterator<? extends Map.Entry<TransmittableThreadLocal<?>, ?>> iterator = holder.get().entrySet().iterator();
iterator.hasNext(); ) {
Map.Entry<TransmittableThreadLocal<?>, ?> next = iterator.next();
TransmittableThreadLocal<?> threadLocal = next.getKey();
// backup
backup.put(threadLocal, threadLocal.get());
// clear the TTL values that is not in captured
// avoid the extra TTL values after replay when run task
if (!capturedMap.containsKey(threadLocal)) {
iterator.remove();
threadLocal.superRemove();
}
}
// set values to captured TTL
setTtlValuesTo(capturedMap);
// call beforeExecute callback
doExecuteCallback(true);
return backup;
}
/**
* Clear all {@link TransmittableThreadLocal} values in current thread,
* and return the backup {@link TransmittableThreadLocal} values in current thread before clear.
*
* @return the backup {@link TransmittableThreadLocal} values before clear
* @since 2.9.0
*/
@Nonnull
public static Object clear() {
return replay(Collections.emptyMap());
}
/**
* Restore the backup {@link TransmittableThreadLocal} values from {@link #replay(Object)}/{@link #clear()}.
*
* @param backup the backup {@link TransmittableThreadLocal} values from {@link #replay(Object)}/{@link #clear()}
* @see #replay(Object)
* @see #clear()
* @since 2.3.0
*/
public static void restore(@Nonnull Object backup) {
@SuppressWarnings("unchecked")
Map<TransmittableThreadLocal<?>, Object> backupMap = (Map<TransmittableThreadLocal<?>, Object>) backup;
// call afterExecute callback
doExecuteCallback(false);
for (Iterator<? extends Map.Entry<TransmittableThreadLocal<?>, ?>> iterator = holder.get().entrySet().iterator();
iterator.hasNext(); ) {
Map.Entry<TransmittableThreadLocal<?>, ?> next = iterator.next();
TransmittableThreadLocal<?> threadLocal = next.getKey();
// clear the TTL values that is not in backup
// avoid the extra TTL values after restore
if (!backupMap.containsKey(threadLocal)) {
iterator.remove();
threadLocal.superRemove();
}
}
// restore TTL values
setTtlValuesTo(backupMap);
}
private static void setTtlValuesTo(@Nonnull Map<TransmittableThreadLocal<?>, Object> ttlValues) {
for (Map.Entry<TransmittableThreadLocal<?>, Object> entry : ttlValues.entrySet()) {
@SuppressWarnings("unchecked")
TransmittableThreadLocal<Object> threadLocal = (TransmittableThreadLocal<Object>) entry.getKey();
threadLocal.set(entry.getValue());
}
}