Is this approach standard to use varags.length instead of booleans?

Ali :

I've called this method multiple times in many places:

private String changeFirstCharCase(String word) {
    return Character.toLowerCase(word.charAt(0)) + word.substring(1);
}

now I want to add toUpperCase ability to this method without creating another method and I need the caller to determine which one to go with using a boolean as an arguement.

private static String changeFirstCharCase(String word, boolean toUpperCase) {
    return toUpperCase
            ? Character.toUpperCase(word.charAt(0)) + word.substring(1)
            : Character.toLowerCase(word.charAt(0)) + word.substring(1);
}

in this case I've to add a true/false parameter to every call I've made. but when I use varags, the calls that only need the toUpperCase ability need to add their note, which could be anything.

private static String changeFirstCharCase(String word, String... toUpperCase) {
    return toUpperCase.length > 0
            ? Character.toUpperCase(word.charAt(0)) + word.substring(1)
            : Character.toLowerCase(word.charAt(0)) + word.substring(1);
}

in this way the old methods calls are untouched.

changeFirstCharCase(facadeType);

and the new ones can call:

changeFirstCharCase(facadeType, "toUpperCase")

is this aprouch standard in case of readability and maintenance?

Eran :

This looks like poor API design to me. Requiring the users of your API to pass an additional String argument (that could contain anything) in order to get the upper-case functionality is counter-intuitive.

If you don't want to touch the original methods, introduce new overloaded methods with the boolean parameter:

private String changeFirstCharCase(String word) {
    return changeFirstCharCase(word,false);
}

private String changeFirstCharCase(String word,boolean toUpperCase) {
    return toUpperCase
        ? Character.toUpperCase(word.charAt(0)) + word.substring(1)
        : Character.toLowerCase(word.charAt(0)) + word.substring(1);
}

or introduce a new method for the upper-case functionality, without the boolean parameter:

private String changeFirstCharCase(String word) {
    return Character.toLowerCase(word.charAt(0)) + word.substring(1);
}

private String changeFirstCharToUpperCase(String word) {
    return Character.toUpperCase(word.charAt(0)) + word.substring(1);
}

Though in this case it would also make sense to rename the original method to changeFirstCharToLowerCase.