package src::bo::Duck;

use strict;
use warnings;

use Carp;

sub new {
    my $class = shift;
    my $self = {
        FLYBEHAVIOUR => { 'VALUE' => undef, 'ACCESS' => 'protected' },
        QUACKBEHAVIOUR => { 'VALUE' => undef, 'ACCESS' => 'protected' },
    };
    my $closure = sub {
        my $field = shift;
        $self->{$field}->{'ACCESS'} eq 'private' 
            and caller(0) eq __PACKAGE__
            || confess "$field is private";
        $self->{$field}->{'ACCESS'} eq 'protected' 
            and caller(0)->isa(__PACKAGE__)
            || confess "$field is protected";
        if ( @_ ) { $self->{$field}->{'VALUE'} = shift; }
        return $self->{$field}->{'VALUE'};
    };
    bless ($closure, $class);
    return $closure;
}

sub setFlyBehaviour {
    caller(0)->isa(__PACKAGE__) || confess "setFlyBehaviour is protected";
    my $closure      = shift;
    my $flyBehaviour = shift;
    &{ $closure }("FLYBEHAVIOUR", $flyBehaviour);
}
    
sub setQuackBehaviour { 
    caller(0)->isa(__PACKAGE__) || confess "setQuackBehaviour is protected";
    my $closure      = shift;
    my $quackBehaviour = shift;
    &{ $closure }("QUACKBEHAVIOUR", $quackBehaviour);
}
    
sub doFly {
    my $closure = shift;
    &{ $closure }("FLYBEHAVIOUR")->fly();
}

sub doQuack() {
    my $closure = shift;
    &{ $closure }("QUACKBEHAVIOUR")->quack();
}

1;