There is a design pattern that does what you want it to do. It's called a (I think) facade. The idea is that you have a bunch of layers over an object that will trap calls to a method and validate whatever. Once that actual object's method is called, it can assume the input data is good.

Somebody almost certainly has documented filters as a design pattern - but it's not a facade :-)

A facade is when you hide the details of using a group of objects behind a simple interface (e.g. LWP::Simple is a facade for LWP::UserAgent et al.)

There's an article on facade's in 0.4 edition of the Perl Review for those interested.

In reply to Re^2: Filter objects? by adrianh
in thread Filter objects? by matth

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