Question

You have

[e-mail]

and result should be:

******@domain.com

Currently I’m doing it this way:

public static String removeUserFromEmail(String email) {
    StringBuffer sbEmail = new StringBuffer(email);
    int start = sbEmail.indexOf("@");
    sbEmail.delete(0, start);
    return "******" + sbEmail.toString();
}

Is there something simpler or more elegant?

Answer 1

Nothing wrong with that solution, although I have two suggestions:

1) Use StringBuilder instead of StringBuffer unless you need to synchronize access between multiple threads. There is a performance penalty associated with StringBuffer that for this application is likely unnecessary.

2) One of the benefits of StringBuilder/Buffer is avoiding excessive string concatenations.

Your return line converts the Buffer to a string, and then concatenates. I would probably do this instead:

int start = email.indexOf("@");

if (start < 0) {
    return "";  // pick your poison for the error condition
}

StringBuilder sbEmail = new StringBuilder(email);
sbEmail.replace(0, start, "******");
return sbEmail.toString();

FYI – my solution is really just some thoughts on your current use of StringBuffer (which are hopefully helpful). I would recommend Konstantin’s solution for this simple string exercise. Simple, readable, and it gives you the opportunity to handle the error condition.