<p>This method allows the application to query the parent
reader (which may be another filter). It is generally a
bad idea to perform any operations on the parent reader
directly: they should all pass through this filter.</p>
@return The parent filter, or null if none has been set.
Get the parent reader.
<p>This method allows the application to query the parent reader (which may be another filter). It is generally a bad idea to perform any operations on the parent reader directly: they should all pass through this filter.</p>
@return The parent filter, or null if none has been set.