package TaskFilter;

use base 'Task';

sub prefilter
{ 1 } # default pre is to do nothing and succeed at it.

sub postfilter
{ 1 } # same thing

sub filter
{ die "need to implement filter in subclass '" . ref $_[0] . "'\n"; }

sub get_object_list
{
  # generic implementation common to all my tasks derived from here.
}

sub sort_object_list
{
  # to allow subclass to change order if needed.
  sort @_
}

sub perform_task {
  my $self = shift;
  $self->prefilter() or die "prefilter failed.";

  my @records = $self->sort_object_list($self->get_object_list());
  for my $r (@records)
  {
    $self->filter($r);
  }

  $self->postfilter() or die "postfilter failed.";
  1;
}

1;