Class LocaleContextHolder

java.lang.Object
org.springframework.context.i18n.LocaleContextHolder
public final class LocaleContextHolder extends Object
Simple holder class that associates a LocaleContext instance with the current thread. The LocaleContext will be inherited by any child threads spawned by the current thread if the inheritable flag is set to true.

Note, the inheritable flag relies on JDK InheritableThreadLocal semantics, which only propagates the context value to newly created child threads at the time of their creation. In thread pool environments where threads are reused across tasks, the context is not refreshed per task submission; reused threads retain whatever value was inherited when they were originally created. This mechanism is therefore not suitable for per-task context propagation in thread pool environments. Instead, consider using a TaskDecorator that captures the locale context in the caller thread, applies it around each task execution, and resets it afterward. The inheritable flag works as expected with virtual threads, since those are newly created for every task.

Used as a central holder for the current Locale in Spring, wherever necessary: for example, in MessageSourceAccessor. DispatcherServlet automatically exposes its current Locale here. Other applications can expose theirs too, to make classes like MessageSourceAccessor automatically use that Locale.

Since:
1.2
Author:
Juergen Hoeller, Nicholas Williams
See Also:

  • Method Details

    • resetLocaleContext

      public static void resetLocaleContext()
      Reset the LocaleContext for the current thread.

    • setLocaleContext

      public static void setLocaleContext(@Nullable LocaleContext localeContext)
      Associate the given LocaleContext with the current thread, not exposing it as inheritable for child threads.

      The given LocaleContext may be a TimeZoneAwareLocaleContext, containing a locale with associated time zone information.

      Parameters:
      localeContext - the current LocaleContext, or null to reset the thread-bound context
      See Also:

    • setLocaleContext

      public static void setLocaleContext(@Nullable LocaleContext localeContext, boolean inheritable)
      Associate the given LocaleContext with the current thread.

      The given LocaleContext may be a TimeZoneAwareLocaleContext, containing a locale with associated time zone information.

      Parameters:
      localeContext - the current LocaleContext, or null to reset the thread-bound context
      inheritable - whether to expose the LocaleContext as inheritable for child threads (using an InheritableThreadLocal); note that this only propagates to newly created threads, not to threads reused in a thread pool (see the class-level note for details)
      See Also:

    • getLocaleContext

      public static @Nullable LocaleContext getLocaleContext()
      Return the LocaleContext associated with the current thread, if any.
      Returns:
      the current LocaleContext, or null if none

    • setLocale

      public static void setLocale(@Nullable Locale locale)
      Associate the given Locale with the current thread, preserving any TimeZone that may have been set already.

      Will implicitly create a LocaleContext for the given Locale, not exposing it as inheritable for child threads.

      Parameters:
      locale - the current Locale, or null to reset the locale part of thread-bound context
      See Also:

    • setLocale

      public static void setLocale(@Nullable Locale locale, boolean inheritable)
      Associate the given Locale with the current thread, preserving any TimeZone that may have been set already.

      Will implicitly create a LocaleContext for the given Locale.

      Parameters:
      locale - the current Locale, or null to reset the locale part of thread-bound context
      inheritable - whether to expose the LocaleContext as inheritable for child threads (using an InheritableThreadLocal)
      See Also:

    • setDefaultLocale

      public static void setDefaultLocale(@Nullable Locale locale)
      Set a shared default locale at the framework level, as an alternative to the JVM-wide default locale.

      NOTE: This can be useful to set an application-level default locale which differs from the JVM-wide default locale. However, this requires each such application to operate against locally deployed Spring Framework jars. Do not deploy Spring as a shared library at the server level in such a scenario!

      Parameters:
      locale - the default locale (or null for none, letting lookups fall back to Locale.getDefault())
      Since:
      4.3.5
      See Also:

    • getLocale

      public static Locale getLocale()
      Return the Locale associated with the current thread, if any, or the system default Locale otherwise. This is effectively a replacement for Locale.getDefault(), able to optionally respect a user-level Locale setting.

      Note: This method has a fallback to the shared default Locale, either at the framework level or at the JVM-wide system level. If you'd like to check for the raw LocaleContext content (which may indicate no specific locale through null, use getLocaleContext() and call LocaleContext.getLocale()

      Returns:
      the current Locale, or the system default Locale if no specific Locale has been associated with the current thread
      See Also:

    • getLocale

      public static Locale getLocale(@Nullable LocaleContext localeContext)
      Return the Locale associated with the given user context, if any, or the system default Locale otherwise. This is effectively a replacement for Locale.getDefault(), able to optionally respect a user-level Locale setting.
      Parameters:
      localeContext - the user-level locale context to check
      Returns:
      the current Locale, or the system default Locale if no specific Locale has been associated with the current thread
      Since:
      5.0
      See Also:

    • setTimeZone

      public static void setTimeZone(@Nullable TimeZone timeZone)
      Associate the given TimeZone with the current thread, preserving any Locale that may have been set already.

      Will implicitly create a LocaleContext for the given Locale, not exposing it as inheritable for child threads.

      Parameters:
      timeZone - the current TimeZone, or null to reset the time zone part of the thread-bound context
      See Also:

    • setTimeZone

      public static void setTimeZone(@Nullable TimeZone timeZone, boolean inheritable)
      Associate the given TimeZone with the current thread, preserving any Locale that may have been set already.

      Will implicitly create a LocaleContext for the given Locale.

      Parameters:
      timeZone - the current TimeZone, or null to reset the time zone part of the thread-bound context
      inheritable - whether to expose the LocaleContext as inheritable for child threads (using an InheritableThreadLocal)
      See Also:

    • setDefaultTimeZone

      public static void setDefaultTimeZone(@Nullable TimeZone timeZone)
      Set a shared default time zone at the framework level, as an alternative to the JVM-wide default time zone.

      NOTE: This can be useful to set an application-level default time zone which differs from the JVM-wide default time zone. However, this requires each such application to operate against locally deployed Spring Framework jars. Do not deploy Spring as a shared library at the server level in such a scenario!

      Parameters:
      timeZone - the default time zone (or null for none, letting lookups fall back to TimeZone.getDefault())
      Since:
      4.3.5
      See Also:

    • getTimeZone

      public static TimeZone getTimeZone()
      Return the TimeZone associated with the current thread, if any, or the system default TimeZone otherwise. This is effectively a replacement for TimeZone.getDefault(), able to optionally respect a user-level TimeZone setting.

      Note: This method has a fallback to the shared default TimeZone, either at the framework level or at the JVM-wide system level. If you'd like to check for the raw LocaleContext content (which may indicate no specific time zone through null), use getLocaleContext() and call TimeZoneAwareLocaleContext.getTimeZone() after downcasting to TimeZoneAwareLocaleContext.

      Returns:
      the current TimeZone, or the system default TimeZone if no specific TimeZone has been associated with the current thread
      See Also:

    • getTimeZone

      public static TimeZone getTimeZone(@Nullable LocaleContext localeContext)
      Return the TimeZone associated with the given user context, if any, or the system default TimeZone otherwise. This is effectively a replacement for TimeZone.getDefault(), able to optionally respect a user-level TimeZone setting.
      Parameters:
      localeContext - the user-level locale context to check
      Returns:
      the current TimeZone, or the system default TimeZone if no specific TimeZone has been associated with the current thread
      Since:
      5.0
      See Also: