issue with validation with datamapper

[eluser]johnmerlino[/eluser]
[quote author="WanWizard" date="1306016787"]

Code:

$user->password($this->input->post('password'));

calls a method called 'password', which does not exist. That's what the error message says...

Datamapper captures calls for unknown methods, that's how it deals with all where_... variations, so that's why you get this error message instead of the standard PHP error.[/quote]

Now let's say you didn't have a database table and you didnt have a model, because for one form submission, all it is intended to be is a contact us, where the information gets sent to the admin user in an email, but nothing gets stored in data table. Yet, you have your typically input fields that will get passed into an email. How is one supposed to validate those input fields if you dont have a database table or model for the form?