java - Replace all occurrences of a String using StringBuilder?

Question

Am I missing something, or does StringBuilder lack the same "replace all occurrences of a string A with string B" function that the normal String class does? The StringBuilder replace function isn't quite the same. Is there any way to this more efficiently without generating multiple Strings using the normal String class?

Answer 1

Well, you can write a loop:

public static void replaceAll(StringBuilder builder, String from, String to) {
    int index = builder.indexOf(from);
    while (index != -1) {
        builder.replace(index, index + from.length(), to);
        index += to.length(); // Move to the end of the replacement
        index = builder.indexOf(from, index);
    }
}

Note that in some cases it may be faster to use lastIndexOf, working from the back. I suspect that's the case if you're replacing a long string with a short one - so when you get to the start, any replacements have less to copy. Anyway, this should give you a starting point.