in src/main/java/org/apache/sling/auth/xing/login/impl/XingLoginLoginModulePlugin.java [73:79]
public boolean canHandle(final Credentials credentials) {
logger.debug("canHandle({})", credentials);
final String hash = XingLoginUtil.getHash(credentials);
final String user = XingLoginUtil.getUser(credentials);
logger.debug("hash: {}, user: {}", hash, user);
return hash != null && user != null;
}