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From Henri Yandell <>
Subject [lang] LANG-510
Date Fri, 05 Mar 2010 09:32:38 GMT
Thinking further on moving StringUtils to CharSequence, I'd like to
take the String left(String, int) method as an example. It depends on
substring(int, int), so is entirely possibly to move over to
subSequence(int, int).

Hypothetical new method:

    CharSequence left(CharSequence, int)

The downside here is that users currently storing this in a String are
going to have to cast. Generics to the rescue.

    <T extends CharSequence> T left(T, int)

This hits two problems:

1) EMPTY is returned when the int is less than 0; EMPTY is a String and not T.
2) subSequence returns CharSequence and not T.

I could add a wrapper method to make Strings nicer:

    public static String left(String str, int len) {
        if (str == null) {
            return null;
        return left( (CharSequence) str, len).toString();

But that doesn't help the StringBuffer/StrBuilder/StringBuilder user;
they still get a sucky API.

Am I missing anything obvious here, or should I give up the ghost on
trying to take these methods to CharSequence APIs?


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