This interface defines how a wavelet filter implementation should present itself. This interface defines only the commonalities between the analysis and synthesis filters. The AnWTFilter and SynWTFilter classes provide the specifics of analysis and synthesis filters.

       <p>Both analysis and filters must be able to return the extent of the
       negative and positive support for both synthesis and analysis sides. This
       simplifies the sue of some functionalities that need extra information
       about the filters.</p>