* @param context caller can pass this object in (used for thread safety)
* @return number of catalog references opened and crawled
*/
public int crawl(String catUrl, CancelTask task, PrintStream out, Object context) {
InvCatalogFactory catFactory = InvCatalogFactory.getDefaultFactory(true);
InvCatalogImpl cat = catFactory.readXML(catUrl);
StringBuilder buff = new StringBuilder();
boolean isValid = cat.check(buff, false);
if (out != null) {
out.println("catalog <" + cat.getName() + "> " + (isValid ? "is" : "is not") + " valid");