constructor TSAXParser.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  FLine := 0;
  FColumn := 0;
  FAttributeList := TSXPAttributeList.Create;
  // create an instance of the Reader COM object
  FReader := CreateComObject(CLASS_SAXXMLReader) as ISAXXMLReader;
  // instantiate the handler classes
  FErrorHandler   := TSAXErrorHandler.Create;
  FLexicalHandler := TSAXLexicalHandler.Create;
  FContenthandler := TSAXContentHandler.Create;
  FDTDHandler     := TSAXDTDHandler.Create;
  FDeclHandler    := TSAXDeclhandler.Create;
  FContentHandler.FDocumentLocator := Nil;
  // Handlers need a reference pointing back to us
  // because they will continually update
  // our Line and Column properties on each event
  FLexicalhandler.SAXParser := Self;
  FContenthandler.SAXParser := Self;
  FDTDHandler.SAXParser := Self;
  FDeclHandler.SAXParser := Self;
  // pass the handler implementations to the reader
  FReader.putErrorHandler(FErrorhandler);
  FReader.putContentHandler(FContentHandler);
  FReader.putDTDHandler(FDTDHandler);
  Freader.putProperty('http://xml.org/sax/properties/lexical-handler',
                      FLexicalhandler as ISAXLexicalHandler);
  Freader.putProperty('http://xml.org/sax/properties/declaration-handler',
                      FDeclhandler as ISAXdeclHandler);
end;

Example 3: Constructor of TSAXParser instantiates the reader and the handler classes, and passes the handlers to the readers.