This interface receives notification of basic DTD-related events.
If a SAX application needs information about notations and unparsed entities, then the application implements this interface and registers an instance with the SAX parser using the parser’s setDTDHandler method. The parser uses the instance to report notation and unparsed entity declarations to the application.
The SAX parser may report these events in any order, regardless of the order in which the notations and unparsed entities were declared; however, all DTD events must be reported after the document handler’s startDocument event, and before the first startElement event.
It is up to the application to store the information for future use (perhaps in a hash table or object tree). If the application encounters attributes of type “NOTATION”, “ENTITY”, or “ENTITIES”, it can use the information that it obtained through this interface to find the entity and/or notation corresponding with the attribute value.
The specification extends the Java org.xml.sax.DTDHandler with the following methods:
int enableExceptions (int enable);