Resets this stream to the beginning. This is an optional operation, so subclasses may or may not implement this method. {@link #Reset()} is not needed for the standard indexing process. However, if the tokens of a

CopyC#

TokenStream

are intended to be consumed more than once, it is necessary to implement {@link #Reset()}. Note that if your TokenStream caches tokens and feeds them back again after a reset, it is imperative that you clone the tokens when you store them away (on the first pass) as well as when you return them (on future passes after {@link #Reset()}).