Ignore/don't persist a model if certain attribute is blank or some value

[Victor Stan]

Hi, I can't find any information about how to run a before filter in a model or a condition check, that will indicate the model instance should be ignored/not persisted if the check return true or some other value.

Basically, I want a mechanism that will ignore the call to persist/save/create a model instance if a certain attribute is blank, that I can call from within the model itself. Is this possible? 

It should not be something that I do on the controller side btw.

Any pointers appreciated!

[Colin Law]

This is exactly what model validations do, for example
validates_presence_of will cause a save/update to fail if the
attribute is not set.

Colin