[Perl-workflow-devel] Persister::DBI subclassing issues

[Jim B. <cb...@bu...>]

I've just finished subclassing Workflow::DBI::Persister and ran into a 
few problems I wanted to share. Don't have any specific solutions just 
yet, just my work-arounds:

1) I don't think you can actually just subclass as shown here:

http://search.cpan.org/~jonasbn/Workflow-0.26/lib/Workflow/Persister/DBI.pm

unless you call SUPER::init because you'll get a $log not defined error 
when the code hits assign_generators. This is because the $log ||= 
get_logger is below the first $log call. I think if it gets moved up, 
the problem will be fixed:

sub assign_generators {
     my ( $self, $params, $driver ) = @_;
     $log ||= get_logger();
     $log->is_debug &&
         $log->debug( "assign_generators with $self, $params, $driver" );
     $self->SUPER::assign_generators( $params );
     return if ( $self->workflow_id_generator and
                 $self->history_id_generator );

move this up -->    $log ||= get_logger();
     my ( $wf_gen, $history_gen );

2) I think the 'assign_generators' example on the page has the params 
backwards. It shows:

     $self->assign_generators( $ds_config->{driver_name}, $params );

But I think that method wants $params first.

3) There doesn't seem to be an easy way to subclass the Persister and 
use ExtraData at the same time. I did it by subclassing ExtraData.pm, 
but I had to copy most of init and chop out a few things since I didn't 
want to call SUPER::init.

Maybe pull out the parts that load the extra values into a separate sub 
so if you subclass you just need to add a call to:

$self->load_extra_data();

to your init? Just a thought. I'm sure there are other solutions.

As I said, sorry I don't have actual patches right now. I just wanted to 
capture the info while it was fresh.


Jim


-- 
Jim Brandt
Administrative Computing Services
University at Buffalo