code: @Nullable
    @MustBeLocked (ELockType.READ)
    protected final IMPLTYPE internalGetOfID (@Nullable final String sID)
    {
      if (StringHelper.hasNoText (sID))
        return null;
  
      return m_aMap.get (sID);
    }
docs: Same as {@link #getOfID(String)} but the locking must happen on the called
  side.
  
  @param sID
  The ID to search. May be <code>null</code>.
  @return <code>null</code> if no such item exists
  @since 9.1.5