Question

Given that an input String may be specified as follows:

• read(xpath(‘…’)) or
• xpath(‘…’) or
• …

Where … just holds some xpath expression, for example,/comment/text

All I really want is the xpath expression; what would be an efficient way to in general extract this value given the three possible valid patterns that could be specified.

Also, I am implementing this in Java.

Answer 1

Here is the basic example, it matches xpath part in both of your string examples:

import java.util.regex.*;

class Untitled {
  public static void main(String[] args) {
    String input = "read(xpath('...'))";
    String result = null;
    Pattern regex = Pattern.compile("xpath\\(\'(.*?)\'\\)");
    Matcher matcher = regex.matcher(input);

    if (matcher.find()) {
        result = matcher.group(1);
    }

    System.out.println(result);
  }
}