sub foo {
    my $self = shift;
    $self->query->param('id');
    if (!$id) {return $self->get_id();}
#get_id returns a web page that prompts the user for an id
#this is all running in mod_perl, with CGI::Application
    my $obj = $self->get_obj($id);
    #else do foo kinda stuff with $obj
}