code: public StrBuilder replaceAll(final String searchStr, final String replaceStr) {
          final int searchLen = (searchStr == null ? 0 : searchStr.length());
          if (searchLen > 0) {
              final int replaceLen = (replaceStr == null ? 0 : replaceStr.length());
              int index = indexOf(searchStr, 0);
              while (index >= 0) {
                  replaceImpl(index, index + searchLen, searchLen, replaceStr, replaceLen);
                  index = indexOf(searchStr, index + replaceLen);
              }
          }
          return this;
      }
docs: Replaces the search string with the replace string throughout the builder.
  
  @param searchStr  the search string, null causes no action to occur
  @param replaceStr  the replace string, null is equivalent to an empty string
  @return this, to enable chaining