无法让Matcher.replaceAll正常工作

Question

I am having some weird issues with a pattern replace.

I have these two patterns:

private static final Pattern CODE_ANY = Pattern.compile("&[0-9a-fk-or]");
private static final Pattern CODE_BLACK = Pattern.compile(ChatColour.BLACK.toString());

ChatColour.BLACK.toString() returns "&0"

Next, I have this code:

public static String Strip(String message)
{
    while (true)
    {
        Matcher matcher = CODE_ANY.matcher(message);
        if (!matcher.matches())
            break;
        message = matcher.replaceAll("");
    }
    return message;
}

I have tried a couple different approaches, but nothing gets replaced. The initial version just called each CODE_xxx pattern one after the other, but users were bypassing that by doubling up on ampersands.

I just do not understand why this isn't removing anything.. I know it is definitely getting called, as I have printed debug messages to the console to check that.

// Morten

Answer 1

matches() checks if the complete input string matches the pattern, whereas find() checks if the pattern can be found somewhere in the input string. Therefor, I would rewrite your method as:

public static String strip(String message) // lowercase strip due to Java naming conventions
{
    Matcher matcher = CODE_ANY.matcher(message);
    if (matcher.find())
        message = matcher.replaceAll("");
    return message;
}

---

Just realized, this can be done with a one liner:

public static String strip(String message) {
    return message.replaceAll("&[0-9a-fk-or]", "");
}

Using the replaceAll() method you don't need a precompiled pattern, but you could extract the regex to a final field of type String.