/**
* Attempts to validate the given XML string using Java's XML validation facility. Requires Java
* 1.5+.
*
* @param xml The XML string to validate.
* @param label String describing the type of XML being validated.
* @return whether or not validation was successful.
*/
public static boolean validateXML(String xml, String label) {
if (label == null) label = "XML";
Exception exception = null;
// get path to schema from root element using SAX
LOGGER.info("Parsing schema path");
ValidationSAXHandler saxHandler = new ValidationSAXHandler();
try {
// Java XML factories are not declared to be thread safe
SAXParserFactory factory = SAXParserFactory.newInstance();
SAXParser saxParser = factory.newSAXParser();
InputStream is = new ByteArrayInputStream(xml.getBytes(Constants.ENCODING));
saxParser.parse(is, saxHandler);
} catch (ParserConfigurationException exc) {
exception = exc;
} catch (SAXException exc) {
exception = exc;
} catch (IOException exc) {
exception = exc;
}
if (exception != null) {
LOGGER.warn("Error parsing schema path from {}", label, exception);
return false;
}
String schemaPath = saxHandler.getSchemaPath();
if (schemaPath == null) {
LOGGER.error("No schema path found. Validation cannot continue.");
return false;
}
LOGGER.info(schemaPath);
LOGGER.info("Validating {}", label);
// compile the schema
URI schemaLocation = null;
try {
schemaLocation = new URI(schemaPath);
} catch (URISyntaxException exc) {
LOGGER.info("Error accessing schema at {}", schemaPath, exc);
return false;
}
Schema schema = schemas.get().get(schemaLocation);
if (schema == null) {
try {
schema = FACTORY.newSchema(schemaLocation.toURL());
schemas.get().put(schemaLocation, schema);
} catch (MalformedURLException exc) {
LOGGER.info("Error parsing schema at {}", schemaPath, exc);
return false;
} catch (SAXException exc) {
LOGGER.info("Error parsing schema at {}", schemaPath, exc);
return false;
}
}
// get a validator from the schema
Validator validator = schema.newValidator();
// prepare the XML source
StringReader reader = new StringReader(xml);
InputSource is = new InputSource(reader);
SAXSource source = new SAXSource(is);
// validate the XML
ValidationErrorHandler errorHandler = new ValidationErrorHandler();
validator.setErrorHandler(errorHandler);
try {
validator.validate(source);
} catch (IOException exc) {
exception = exc;
} catch (SAXException exc) {
exception = exc;
}
final int errors = errorHandler.getErrorCount();
if (errors > 0) {
LOGGER.info("Error validating document: {} errors found", errors);
return false;
} else LOGGER.info("No validation errors found.");
return errorHandler.ok();
}
