code: @Nonnegative
    public static int removeAllTokensOfSubject (@Nonnull final IAuthSubject aSubject)
    {
      ValueEnforcer.notNull (aSubject, "Subject");
  
      // get all token IDs matching a given subject
      // Note: required IAuthSubject to implement equals!
      final ICommonsList <String> aDelTokenIDs = new CommonsArrayList <> ();
      s_aRWLock.readLocked ( () -> {
        for (final Map.Entry <String, AuthToken> aEntry : s_aMap.entrySet ())
          if (aEntry.getValue ().getIdentification ().hasAuthSubject (aSubject))
            aDelTokenIDs.add (aEntry.getKey ());
      });
  
      for (final String sDelTokenID : aDelTokenIDs)
        removeToken (sDelTokenID);
  
      return aDelTokenIDs.size ();
    }
docs: Remove all tokens of the given subject
  
  @param aSubject
  The subject for which the tokens should be removed.
  @return The number of removed tokens. Always &ge; 0.