Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.java.help > #1638

Re: Validating form inputs?

Show all headers | View raw

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".

> There are a few frameworks that do this in several phases actually. Its 
> called binding and validating.
> 
> In the binding phase, values are parsed into appropriate data types, and 
> stored in the model (Form object as it is sometimes called).  If the 
> data can not be parsed, or the model rejects the value immediately, it 
> is a binding error.
> 
> In the validation phase, the values are checked for correctness. This is 
> often a secondary phase because some values are interdependent.
> 
> If, after validation, you want to have an immutable object, then you 
> could treat your Form object more as a Builder object, and have it 
> construct the Real object, which is fully populated and validated. 
> Alternatively, you could use the Form object as a "Parameter" object for 
> a different Builder class, to keep the concerns of the Form object more 
> pure.
> 
> I suggest looking into different frameworks, rather than trying to 
> roll-your-own. There are a lot of gotchas that can be avoided, and 
> boilerplate code you can rid yourself of.  I've had moderate luck with 
> Spring Binding.  If you have typical use-cases it works well.  If you 
> have more complicated forms, for instance complex dynamic items, then 
> there is some shoehorning needed to make it work correctly.

Rolling your own isn't actually that hard, but you won't get the breadth, depth or solidity of a framework with thousands of manhours invested in it already. Then again, you might not need all that.

There are plenty of better frameworks out there than Spring. There's JSF, regular old JSP with EL and JSTL, and Struts, to name three.

Your use of the term "class methods", OP, suggests that you need to study Java some more, and likely also servlets and presentation technologies some more. Look up the "Model 2" web-application paradigm. Then go with JSP/EL or JSF/Facelets.

-- 
Lew

Back to comp.lang.java.help | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

Validating form inputs? Davej <galt_57@hotmail.com> - 2012-03-20 11:16 -0700
  Re: Validating form inputs? Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2012-03-20 12:08 -0700
    Re: Validating form inputs? Lew <lewbloch@gmail.com> - 2012-03-20 12:50 -0700
      Re: Validating form inputs? markspace <-@.> - 2012-03-21 09:24 -0700
      Re: Validating form inputs? Davej <galt_57@hotmail.com> - 2012-03-21 12:02 -0700
        Re: Validating form inputs? Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2012-03-21 12:59 -0700
        Re: Validating form inputs? Lew <lewbloch@gmail.com> - 2012-03-21 13:37 -0700
    Re: Validating form inputs? Davej <galt_57@hotmail.com> - 2012-03-20 12:56 -0700
      Re: Validating form inputs? Lew <lewbloch@gmail.com> - 2012-03-20 13:58 -0700
      Re: Validating form inputs? markspace <-@.> - 2012-03-21 09:30 -0700
  Re: Validating form inputs? Roedy Green <see_website@mindprod.com.invalid> - 2012-03-20 14:28 -0700
    Re: Validating form inputs? Gene Wirchenko <genew@ocis.net> - 2012-03-20 19:16 -0700
      Re: Validating form inputs? Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2012-03-21 17:41 -0300
        Re: Validating form inputs? Gene Wirchenko <genew@ocis.net> - 2012-03-21 14:46 -0700
          Re: Validating form inputs? Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2012-03-21 19:54 -0300
        Re: Validating form inputs? Roedy Green <see_website@mindprod.com.invalid> - 2012-03-22 10:34 -0700
      Re: Validating form inputs? Lew <lewbloch@gmail.com> - 2012-03-21 14:56 -0700
        Re: Validating form inputs? Gene Wirchenko <genew@ocis.net> - 2012-03-21 19:09 -0700
          Re: Validating form inputs? Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2012-03-22 08:36 -0700
            Re: Validating form inputs? Gene Wirchenko <genew@ocis.net> - 2012-03-22 09:40 -0700

csiph-web