OO is not just design, OO is for reusability. So, don't write any read and write methods, just use another Class/Module that already exists, in this case IO::All, and call it:

use Class::HPLOO ;

class Foo {

  use IO::All ;

  ## Object initializer:
  sub Foo ($file) {
    $this->{file_data} < io($file) ;
  }

}
[download]

Class::HPLOO is just a module that enables this kind of OO syntax for Perl. But I recommend to learn the pure Perl style, since with it you are free to do anything. But this style above save me a lot of time. ;-P