Java and XML

Error Handlers

In addition to providing the ContentHandler interface for handling parsing events, SAX provides an ErrorHandler interface that can be implemented to treat various error conditions that may arise during parsing. This class works in the same manner as the document handler we have already constructed, but only defines three callback methods. Through these three methods, all possible error conditions are handled and reported by SAX parsers.

Each method receives information about the error or warning that has occurred through a SAXParseException . This object holds the line number that trouble was encountered on, the URI of the document being treated, which could be the parsed document or an external reference within that document, and normal exception details such as a message and a printable stack trace. In addition, each method can throw a SAXException. This may seem a bit odd at first; an exception handler that throws an exception? Keep in mind that what each handler receives is a parsing exception. This can be a warning that should not cause the parsing process to stop or an error that needs to be resolved for parsing to continue; however, the callback may need to perform system I/O or another operation that can throw an exception, and it needs to be able to bubble this exception up the application chain. It can do this through the SAXException the method is allowed to throw.

For example, consider an error handler that receives error notifications and writes those ...