$ cat ChainOfResponsibilityIf.pm
package PM::1081903::ChainOfResponsibilityIf;

use Moose::Role;

requires 'handleRequest';
requires 'addHandler';

1;

##</code><code>##

$ cat CoRHandler.pm
package PM::1081903::CoRHandler;

use Moose;
use Carp qw(confess croak);

with 'PM::1081903::ChainOfResponsibilityIf';

sub handleRequest { 1 }
sub addHandler { 1 }

sub _processCommand { 1 }

1;

##</code><code>##

$ cat GenericCommandHandler.pm
package PM::1081903::GenericCommandHandler;

use Moose;

extends 'PM::1081903::CoRHandler';

override  '_processCommand' => sub { };

1;

##</code><code>##

$ cat GCHSuccessor.pm
package PM::1081903::GCHSuccessor;

use Moose;

has 'successor' => (
    is => 'rw',
    isa => 'PM::1081903::ChainOfResposibilityIf',
);

1;

##</code><code>##

#!/usr/bin/env perl

use strict;
use warnings;

use PM::1081903::GenericCommandHandler;
use PM::1081903::GCHSuccessor;

my $gchs = PM::1081903::GCHSuccessor::->new(
    successor => PM::1081903::GenericCommandHandler::->new()
);

##</code><code>##

Attribute (successor) does not pass the type constraint because: Validation failed for 'PM::1081903::ChainOfResposibilityIf' with value PM::1081903::GenericCommandHandler=HASH(0x7fa22882a610) (not isa PM::1081903::ChainOfResposibilityIf) at /Users/ken/perl5/perlbrew/perls/perl-5.18.1t/lib/site_perl/5.18.1/darwin-thread-multi-2level/Moose/Meta/Attribute.pm line 1279.
	Moose::Meta::Attribute::verify_against_type_constraint('Moose::Meta::Attribute=HASH(0x7fa2292b89e0)', 'PM::1081903::GenericCommandHandler=HASH(0x7fa22882a610)', 'instance', 'PM::1081903::GCHSuccessor=HASH(0x7fa2288525c8)') called at /Users/ken/perl5/perlbrew/perls/perl-5.18.1t/lib/site_perl/5.18.1/darwin-thread-multi-2level/Moose/Meta/Attribute.pm line 1266
	Moose::Meta::Attribute::_coerce_and_verify('Moose::Meta::Attribute=HASH(0x7fa2292b89e0)', 'PM::1081903::GenericCommandHandler=HASH(0x7fa22882a610)', 'PM::1081903::GCHSuccessor=HASH(0x7fa2288525c8)') called at /Users/ken/perl5/perlbrew/perls/perl-5.18.1t/lib/site_perl/5.18.1/darwin-thread-multi-2level/Moose/Meta/Attribute.pm line 536
	Moose::Meta::Attribute::initialize_instance_slot('Moose::Meta::Attribute=HASH(0x7fa2292b89e0)', 'Moose::Meta::Instance=HASH(0x7fa228843e80)', 'PM::1081903::GCHSuccessor=HASH(0x7fa2288525c8)', 'HASH(0x7fa2290d5108)') called at /Users/ken/perl5/perlbrew/perls/perl-5.18.1t/lib/site_perl/5.18.1/darwin-thread-multi-2level/Class/MOP/Class.pm line 525
	Class::MOP::Class::_construct_instance('Moose::Meta::Class=HASH(0x7fa22929a2e8)', 'HASH(0x7fa2290d5108)') called at /Users/ken/perl5/perlbrew/perls/perl-5.18.1t/lib/site_perl/5.18.1/darwin-thread-multi-2level/Class/MOP/Class.pm line 498
	Class::MOP::Class::new_object('Moose::Meta::Class=HASH(0x7fa22929a2e8)', 'HASH(0x7fa2290d5108)') called at /Users/ken/perl5/perlbrew/perls/perl-5.18.1t/lib/site_perl/5.18.1/darwin-thread-multi-2level/Moose/Meta/Class.pm line 284
	Moose::Meta::Class::new_object('Moose::Meta::Class=HASH(0x7fa22929a2e8)', 'HASH(0x7fa2290d5108)') called at /Users/ken/perl5/perlbrew/perls/perl-5.18.1t/lib/site_perl/5.18.1/darwin-thread-multi-2level/Moose/Object.pm line 28
	Moose::Object::new('PM::1081903::GCHSuccessor', 'successor', 'PM::1081903::GenericCommandHandler=HASH(0x7fa22882a610)') called at ./pm_example.pl line 9

##</code><code>##

isa => 'PM::1081903::ChainOfResposibilityIf',

##</code><code>##

isa => 'PM::1081903::CoRHandler',

##</code><code>##

print $gchs->successor->handleRequest(), "\n";