private static int generationOf(String name) {
            int dash = name.lastIndexOf('-');
            if (dash < 0) return 0;
            String suff = name.substring(dash + 1);
            int r = 0;
            for (char ch : suff.toCharArray()) {
                if (ch >= '0' && ch <= '9') {
                    r *= 10;
                    r += (ch - '0');
                } else {
                    break;
                }
            }
            return r;
        }
Creates an instance of FilesArchive managing the given directory
logserver/src/main/java/com/yahoo/logserver/handlers/archive/FilesArchived.java