This class recognizes most of the grammer for an XML processor. Additional support is provided by the XMLEntityHandler, via the XMLEntityReader instances it creates, which are used to process simple constructs like string literals and character data between markup. The XMLDTDScanner class contains the remaining support for the grammer of DTD declarations. When a <!DOCTYPE ...> is found in the document, the scanDoctypeDecl method will then be called and the XMLDocumentScanner subclass is responsible for "connecting" that method to the corresponding method provided by the XMLDTDScanner class.