Regular expression to match a string between @@ in Java

Question

I am using Java Pattern Compile to match substring with a specific pattern and add it to a List.

I want Regular expression to match the following scenarios

1. String starts and ends with (eg @@foo,bar,bla@@)
2. String starts with "@@ and ends with @@"
3. String starts with Hello "@@ and ends with @@", World
4. String starts with Hello "@@ and ends with @@",// This is a comment

The current code is:-

    List<String> matches = new ArrayList<String>();
    Matcher m = Pattern.compile("@@([^@@]*)@@")
                 .matcher(content);
        System.out.println(m.find());
        while (m.find()) {
            matches.add(m.group());
    }

My content is '<script> var bookSrc = "@@book:URL@@",var books_count: @@Count@@, var active = true</script>'

The above code only matches the strings between @@ and the actual result is [@@count@@] and I expect the result to be [@@book:URL@@, @@count@@]

Any help would be appreciated, how should I modify my pattern to accommodate all of the above scenarios.

Answer 1

You call Matcher.find once before the loop is executed. Thererfore the first match is skipped. If you remove

System.out.println(m.find());

it works as expected. You can still test, if there were matches after the loop:

System.out.println(!matches.isEmpty());