code: public static Trie fromString(String str) {
  		String[] components = str.split("/");
  		Trie r = ROOT;
  		for(int i=0;i!=components.length;++i) {
  			r = r.append(components[i]);
  		}
  		return r;
  	}
docs: Construct a Trie from a string, where '/' is the separator.
  s
  @param str
  @return