SAX Parsing Question

Question

During SAX Validation, is there a way to create custom error messages that get put in the SAXParseExceptions?
I don't want to re-implement Schema Validation. Is there a call back method I can impement and register that gets called when a SAXParseException gets generated so that I can stuff my own message in there?

Answer 1

You can create a customised SAX error handler by using the ErrorHandler interface and then providing your own implementations for the standard error(), warning(), and fatalError() methods. Then, just register this error handler with your main SAX processing program.
For example:
import org.xml.sax.ErrorHandler;
import org.xml.sax.SAXParseException;
import org.xml.sax.SAXException;
public class ErrorChecker implements ErrorHandler {
     public ErrorChecker() {
     public void error (SAXParseException e) {
          System.err.println("[Error] " +
                       getLocationString(e) + ": " +
                       e.getMessage());
     public void warning (SAXParseException e) {
          System.err.println("[Warning] " +
                                 getLocationString(e) + ": " +
                                 e.getMessage());
     public void fatalError (SAXParseException e) throws SAXException {
          System.err.println("[Fatal Error] " +
                       getLocationString(e) + ": " +
                       e.getMessage());
          throw e;
     private String getLocationString(SAXParseException e) {
          StringBuffer str = new StringBuffer();
          String systemId = e.getSystemId();
          if (systemId != null) {
               int index = systemId.lastIndexOf('/');
               if (index != -1)
                    systemId = systemId.substring(index + 1);
               str.append(systemId);
          str.append(':');
          str.append(e.getLineNumber());
          str.append(':');
          str.append(e.getColumnNumber());
          return str.toString();
}