DevShed has posted part two of their look at working with bridge classes in PHP5, looking in detail at the decoupling of the data validation from an input form.

In the course of this second tutorial, I'm going to show you how to create a bridge class which will come in handy for decoupling the validation of user-supplied data. There will be a class that defines generically how certain data must be verified, while others will implement different validation methods.

They start with building a simple bridge class, a validator class that defines methods to check strings, numbers, alphabetic, and email values. For each of these types, they create the corresponding bridge class that validates the input. Finally, they tie it all together, validating an example of each, handled inside of try/catch blocks to watch for the errors that might be thrown.