Phew, ok, I think I really got it down good now. I did some more refinement of how things work, too. Here's what I got:

package File::Collector::DateAnalyzer ;

use strict; use warnings;
use Log::Log4perl::Shortcuts qw(:all);
use File::Collector::DateAnalyzer::Iterator;
use parent qw ( File::Collector );

sub add_resources {
  my $s = shift;

  $s->SUPER::add_resources(@_);
  $s->{files}{some_files}         = File::Collector::DateAnalyzer::Ite
+rator->new();
  $s->{files}{other_files}        = File::Collector::DateAnalyzer::Ite
+rator->new();
  $s->_test_blah;
}

sub _test_blah {
  my $s = shift;

  foreach my $file ($s->get_files) {
    $s->{files}{some_files}->add_file($s->{files}{all}{$file});
  }

}

return 1;



package File::Collector::DateAnalyzer::Iterator ;
use strict;
use warnings;

use parent qw (File::Collector::Iterator);
use Log::Log4perl::Shortcuts       qw(:all);

sub print_blah_names {
  my $s = shift;
  print $s->next->{short_path} . "\n\n";
}


1;

package File::Collector::Iterator ;
use strict;
use warnings;

use Carp;
use Log::Log4perl::Shortcuts       qw(:all);

sub new {
  my $class = shift;
  bless [@_], $class;
}

sub next {
  my $s = shift;
  my $last = shift @$s;
  push @$s, $last;
  return  $last;
}

sub add_file {
  my $s = shift;
  pop @$s;
  push @$s, shift;
  push @$s, '';
}

sub print_short_names {
  my $s = shift;
  print $s->next->{short_path} . "\n";
}

sub selected_file {
  my $s = shift;
  $s->[0];
}

sub do {
  my $self = shift;
  bless \$self, 'File::Collector::Iterator::All';
}

sub DESTROY {
  my $s = shift;
  $s->next while ($s->selected_file);
}

{
  package File::Collector::Iterator::All;
  use Log::Log4perl::Shortcuts       qw(:all);
  sub AUTOLOAD {
    our $AUTOLOAD;
    my $self = shift;
    my @method = split /::/, $AUTOLOAD;
    my $method = pop @method;
    $$self->$method(@_) while ($$self->selected_file);
    $$self->next(@_);
  }
}
[download]

A few notes:

Iterator is now a circular queue, terminated with an empty string.

Attributes of File::Collector subclasses are now iterators themselves. This let me get rid of the AUTOLOAD in File::Collector.

I restrucutred File::Collector->{files} as you suggested.

This simple test works:

{
  my $da;

  # 1
 lives_ok { $da = File::Collector::DateAnalyzer->new('t/test_data/many
+_files'); }
   'creates DateAnalyzer object';

 $da->{files}{some_files}->do->print_blah_names;
 $da->{files}{some_files}->do->print_short_names;
}
[download]

I will improve upon the do method calls so I don't have the ugly hashes in there and will use a simple AUTOLOAD so I can do $da->some_files->do->print_blah_names

How does it look to you?