Question

My Question is a design question. Should I use a StringBuilder and read the file line-by-line, or should I replace?

I’m developing a way to read text from a file. Within the file there can be @@GOTO:"C:\path\to\more.txt"@@. I want to replace everything between the two @@s with the contents of C:\path\to\more.txt. Also, within more.txt there could be another @@GOTO:"C:\path\to\evenmore.txt"@@. So I’m thinking doing this recursively would be the best.

I’m thinking of something like this:

private String replaceGoTo(Pattern pattern, String xmlString) throws IOException {
  Matcher match = pattern.matcher(xmlString);
  while (match.find()) {
    String replacText = IOHelper.fileToString(match.group(2));
    String insert = replaceGoTo(pattern, replacText);
    xmlString = xmlString.replace(match.group(1), insert);
  }
  return xmlString;
}

But I wonder if that’s the most effective way to do it because I’m not using a StringBuilder and I could potentially have a lot of information in those Strings.

Note It’s not broken, I’m just asking about whether there’s a better way to do it. Thanks!

Answer 1

Honest answer: Use an existing template library like Freemarker or Velocity.

Literal answer: Matcher has two methods that come in handy for this kind of situation, appendReplacement() and appendTail(). Both require you to use StringBuffer, which is unfortunate, but it’s the most elegant way to solve such a problem.