private WordField[] extract(LinkNeighborhood ln, String urlStr, boolean useImageFeatures)
            throws MalformedURLException {
        List<WordField> words = new ArrayList<>();
        if (useImageFeatures) {
            if (ln.getImgSrc() != null) {
                PaginaURL pageParser = new PaginaURL(new URL("http://"), ln.getImgSrc(), stopwords);
                addFeaturesToWordFieldList(words, pageParser.words(), WordField.SRC);
            }
            addFeaturesToWordFieldList(words, ln.getImgAlt(), WordField.ALT);
        }
        addUrlWordsToWordField(urlStr, words);
        addFeaturesToWordFieldList(words, ln.getAnchor(), WordField.ANCHOR);
        addFeaturesToWordFieldList(words, ln.getAround(), WordField.AROUND);
        return asNonEmptyArray(words);
    }
Extract the information from links as word in the URL, anchor and around links, and converts
it to an Instance object

@param linkNeighboors The LinkNeighborhood instances to be converted to Instance
@param features String[] pre-defined words
@return HashMap mapping url -> instance
ache/src/main/java/achecrawler/link/classifier/builder/LinkNeighborhoodWrapper.java