Validator.java

package org.softlang.company.features.sax;

import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;
import org.xml.sax.helpers.DefaultHandler;

import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;

import java.io.File;
import java.text.*;


/**
 * A SAX-based handler that print XSD-based validation errors
 */
public class Validator extends DefaultHandler {

    private boolean error = false;

    private static MessageFormat message = new MessageFormat("({0}: {1}, {2}): {3}");

    private void print(SAXParseException x) {
        error = true;
        String msg = message.format(new Object[] { 
                x.getSystemId(),
                new Integer(x.getLineNumber()),
                new Integer(x.getColumnNumber()),
                x.getMessage() });
        System.out.println(msg);
    }

    public void warning(SAXParseException x) {
        print(x);
    }

    public void error(SAXParseException x) {
        print(x);
    }

    public void fatalError(SAXParseException x) throws SAXParseException {
        print(x);
        throw x;
    }

    // Required constants
    private static final String SCHEMA_LANGUAGE =
        "http://java.sun.com/xml/jaxp/properties/schemaLanguage";
    private static final String XML_SCHEMA =
        "http://www.w3.org/2001/XMLSchema";
    private static final String SCHEMA_SOURCE =
        "http://java.sun.com/xml/jaxp/properties/schemaSource";

    public static void printFailure(String xmlFile) {
        System.out.println("Validation failed for " + xmlFile);
    }

    public static void printSuccess(String xmlFile) {
        System.out.println("Validation succeeded for " + xmlFile);
    }

    public static boolean validate(String xmlFile, String xsdFile) {
        try {

            // Create a parser factory
            SAXParserFactory sf = SAXParserFactory.newInstance();
            sf.setNamespaceAware(true);
            sf.setValidating(true);
    
            // Create parser and let it do XSD-based validation
            SAXParser sp = sf.newSAXParser();
            sp.setProperty(SCHEMA_LANGUAGE, XML_SCHEMA);
            sp.setProperty(SCHEMA_SOURCE, xsdFile);

            // Validate by parsing
            Validator v = new Validator();
            sp.parse(new File(xmlFile), v);

            // Done
            if (v.error) {
                printFailure(xmlFile);
                return false;
            } else {
                printSuccess(xmlFile);
                return true;
            }
             
        } 
        catch (ParserConfigurationException e) {
            printFailure(xmlFile);
        }
        catch (SAXException e) {
            printFailure(xmlFile);
        }
        catch (Exception e) {
            printFailure(xmlFile);
        }
        return false;
    }

}