Pattern for assigning and transforming String args to target File type, plus validating their existence--all in one compact piece of code

TwoFileArgsValidateExample.groovy

def (f1, f2) = [new File(args[0]), new File(args[1])].each { f -> 
    if (!f.exists() || f.isDirectory()) {
        println "$f does not exist or is a directory"
        System.exit(0);
    } else {
        f
    }
}    

println "$f1 and $f2 provided"

TODO: Generalize this code to deal with type conversion, validation, and expected number of arguments. Instead of exiting upon validation failure, we could return a processed argument back that represents the specific error.