/ 
Class-Accessor-Validated-0.01
River stage zero No dependents
/ Class::Accessor::Validated

NAME

Class::Accessor::Validated - A drop-in companion for Class::Accessor::Fast with constructor validation

SYNOPSIS

package My::Thing;

use strict;
use warnings;

our %ATTRIBUTES = (
    name    => 1,  # required
    color   => 0,  # optional
    enabled => 0,
);

__PACKAGE__->follow_best_practice;
__PACKAGE__->mk_accessors( keys %ATTRIBUTES );

use parent qw(Class::Accessor::Validated Class::Accessor::Fast);

package main;

my $thing = My::Thing->new({
    name    => 'widget',
    enabled => 1,
});

DESCRIPTION

Class::Accessor::Validated is a simple companion to Class::Accessor::Fast that adds lightweight validation to your object constructors. If you've ever passed in an option to your class and wondered why it wasn't being respected it might have been because the class didn't take that option in the first place! This class will at least prevent you from passing in unimplemented options.

It is intended to be used as a subclass:

use parent qw(Class::Accessor::Validated);

It checks that only known attributes are passed to new(), and it enforces required attributes based on a hash your class must define:

our %ATTRIBUTES = (
    foo => 1,   # required
    bar => 0,   # optional
);

Any attribute with a true value is considered required. The rest are optional. If unknown keys are passed, or required keys are missing, the constructor will die() with a descriptive error message.

USAGE

To use Class::Accessor::Validated, your class must:

  • Declare a %ATTRIBUTES package variable that lists all valid constructor parameters.

  • Inherit from Class::Accessor::Validated.

  • Call mk_accessors(keys %ATTRIBUTES) to generate accessors.

No additional methods are exported or injected - only the constructor is affected.

METHODS AND SUBROUTINES

new

my $object = My::Class->new(\%params);

Validates the constructor arguments against your class's %ATTRIBUTES hash.

Dies with a detailed message if:

  • Any invalid keys are passed

  • Any required keys are missing

Otherwise, it delegates to SUPER::new() and returns the constructed object.

One small improvement(?) is that you may pass either a list of key/value pairs or a hash reference to the constrcutor.

SEE ALSO

Class::Accessor::Fast, Class::Accessor

AUTHOR

Rob Lauer

LICENSE

This module is free software. You can redistribute it and/or modify it under the same terms as Perl itself.