Path: csiph.com!eternal-september.org!feeder.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail
From: Cecil Westerhof <Cecil@decebal.nl>
Newsgroups: comp.lang.java.programmer
Subject: Re: How to handle same sanity checks
Date: Thu, 22 Jun 2017 13:21:40 +0200
Organization: Decebal Computing
Lines: 49
Message-ID: <87k244nu7v.fsf@munus.decebal.nl>
References: <87o9tgo0a9.fsf@munus.decebal.nl> <oig626$4rf$1@dont-email.me>
Mime-Version: 1.0
Content-Type: text/plain
Injection-Info: mx02.eternal-september.org; posting-host="e57c15ed9d20cb5f0e1e910deb92a515"; logging-data="18026"; mail-complaints-to="abuse@eternal-september.org";	posting-account="U2FsdGVkX18I4rhK1GyujW4uMNLxrjMT2m1s7wFwvO4="
User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.5 (gnu/linux)
X-Homepage: http://www.decebal.nl/
Cancel-Lock: sha1:2t5a4C3emmuX9az+mRHdEXn3nW0= sha1:Nh4h+Sn3of3zQsn6/91eYXMYhsE=
Xref: csiph.com comp.lang.java.programmer:36695

On Thursday 22 Jun 2017 12:27 CEST, Martin Gregorie wrote:

> On Thu, 22 Jun 2017 11:10:38 +0200, Cecil Westerhof wrote:
>
>> In my code I have several methods that start with:
>> if ((n < MIN_VAL) || (n > MAX_VAL)) {
>> throw new InvalidParameterException(String.format(ERROR_N, n));
>> }
>>
>> That is not really DRY.
>>
>> I could write a method like:
>> private void checkN(n) {
>> if ((n < MIN_VAL) || (n > MAX_VAL)) {
>> throw new InvalidParameterException(String.format(ERROR_N,
>> n));
>> }
>> }
>>
>> And then replace all the checks with a call to checkN. But then the
>> exception is generated in the method checkN instead of the method
>> that has a wrong parameter. What is the best way to handle this?
>
> I agree that using such a method would tidy up the calling code, but

OK, it is not a big no-no then.


> if I used this type of method I'd generalise it to something like
> this:
>
> private void checkInRange(int n, 
> int lowLimit, 
> int highLimit,
> String error)
> {
> String format = "%s: %d is outside range %d - %d";
> if ((n < lowLimit) || (n > highLimit))
> throw new InvalidParameterException(
> String.format(format,error, n, lowLimit, highLimit));
> }

There is only one range, but it is good to keep in mind for when that
changes.

-- 
Cecil Westerhof
Senior Software Engineer
LinkedIn: http://www.linkedin.com/in/cecilwesterhof