/**
* Given a topic, if that topic is a redirect find the target topic of the redirection.
*
* @param parent The topic being queried. If this topic is a redirect then the redirect target
* will be returned, otherwise the topic itself is returned.
* @param attempts The maximum number of child topics to follow. This parameter prevents infinite
* loops if topics redirect back to one another.
* @return If the parent topic is a redirect then this method returns the target topic that is
* being redirected to, otherwise the parent topic is returned.
* @throws DataAccessException Thrown if any error occurs while retrieving data.
*/
public static Topic findRedirectedTopic(Topic parent, int attempts) throws DataAccessException {
int count = attempts;
String target = parent.getRedirectTo();
if (parent.getTopicType() != TopicType.REDIRECT || StringUtils.isBlank(target)) {
logger.error("getRedirectTarget() called for non-redirect topic " + parent.getName());
return parent;
}
// avoid infinite redirection
count++;
if (count > 10) {
// TODO throw new WikiException(new WikiMessage("topic.redirect.infinite"));
return parent;
}
String virtualWiki = parent.getVirtualWiki();
WikiLink wikiLink = LinkUtil.parseWikiLink(virtualWiki, target);
if (wikiLink.getVirtualWiki() != null) {
virtualWiki = wikiLink.getVirtualWiki().getName();
}
// get the topic that is being redirected to
Topic child =
WikiBase.getDataHandler().lookupTopic(virtualWiki, wikiLink.getDestination(), false, null);
if (child == null) {
// child being redirected to doesn't exist, return parent
return parent;
}
if (StringUtils.isBlank(child.getRedirectTo())) {
// found a topic that is not a redirect, return
return child;
}
// child is a redirect, keep looking
return findRedirectedTopic(child, count);
}
