code: @SuppressWarnings("fallthrough")
      @SuppressFBWarnings(justification = "As this is an encoding method the fallthrough is intentional", value = {"SF_SWITCH_NO_DEFAULT"})
      public static void appendEscapedLuceneQuery(StringBuilder buf,
              final CharSequence text) {
  
          if (text == null || buf == null) {
              return;
          }
  
          for (int i = 0; i < text.length(); i++) {
              final char c = text.charAt(i);
              switch (c) {
                  case '+':
                  case '-':
                  case '&':
                  case '|':
                  case '!':
                  case '(':
                  case ')':
                  case '{':
                  case '}':
                  case '[':
                  case ']':
                  case '^':
                  case '"':
                  case '~':
                  case '*':
                  case '?':
                  case ':':
                  case '/':
                  case '\\': //it is supposed to fall through here
                      buf.append('\\');
                  default:
                      buf.append(c);
                      break;
              }
          }
      }
docs: Appends the text to the supplied StringBuilder escaping Lucene control
  characters in the process.
  
  @param buf a StringBuilder to append the escaped text to
  @param text the data to be escaped