An XML filter is like an XML reader, except that it obtains its events from another XML reader rather than a primary source like an XML document or database.
Filters can modify a stream of events as they pass on to the final application.
The XMLFilterImpl helper class provides a convenient base for creating SAX2 filters, by passing on all EntityResolver , DTDHandler , ContentHandler and ErrorHandler events automatically. Set the parent reader. Methods inherited from interface org.xml.sax. The argument may not be null. The parent filter, or null if none has been set.