public void delete(LinkRelevance linkRelevance) {

        String url = linkRelevance.getURL().toString();
        if (exist(linkRelevance) != null) {
            // we don't want to delete the URL file, it is useful to avoid visiting an old url
            double relevance = linkRelevance.getRelevance();
            double negativeRelevance = relevance > 0 ? -1*relevance : relevance;
            urlRelevance.put(url, new LinkRelevance(linkRelevance.getURL(), negativeRelevance, linkRelevance.getType()));
        }
    }
It deletes a URL from frontier (marks as visited).

@param linkRelevance
ache/src/main/java/achecrawler/link/frontier/Frontier.java