=pod

=head1 NAME

Data::Range::Compare::Stream::Iterator::Compare::LayerCake - Compare Result Filtering layer

=head1 SYNOPSIS

  use Data::Range::Compare::Stream;
  use Data::Range::Compare::Stream::Iterator::Array;
  use Data::Range::Compare::Stream::Iterator::Consolidate;
  use Data::Range::Compare::Stream::Iterator::Compare::LayerCake;

  my $iterator_a=Data::Range::Compare::Stream::Iterator::Array->new(
    new_from=>'Data::Range::Compare::Stream',
  );

  # create a new range and add it to the iterator
  $iterator_a->create_range(0,0);

  my $iterator_b=Data::Range::Compare::Stream::Iterator::Array->new(
    new_from=>'Data::Range::Compare::Stream',
  );

  # create a new range and add it to the iterator
  $iterator_b->create_range(1,2);

  $iterator_a->prepare_for_consolidate_asc;
  $iterator_b->prepare_for_consolidate_asc;

  my $consolidate_a=Data::Range::Compare::Stream::Iterator::Consolidate->new($iterator_a);
  my $consolidate_b=Data::Range::Compare::Stream::Iterator::Consolidate->new($iterator_b);
  

  my $compare=new Data::Range::Compare::Stream::Iterator::Compare::LayerCake;

  $compare->add_consolidator($consolidate_a);
  $compare->add_consolidator($consolidate_b);

  while($compare->has_next) {
    # Result objects are instances of: Data::Range::Compare::Stream::Iterator::Compare::Result
    my $result=$compare->get_next;
  }

=head1 DESCRIPTION

This module extends Data::Range::Compare::Stream::Iterator::Compare::Asc.

Data::Range::Compare::Stream::Iterator::Compare::LayerCake compares results from Data::Range::Compare::Stream::Iterator::Consolidate in the following order: Consolidation Asc range_start asc,range_end desc

=head2 OO Methods

=over 3

=item * my $compare=new Data::Range::Compare::Stream::Iterator::Compare::LayerCake;

=item * my $compare=new Data::Range::Compare::Stream::Iterator::Compare::LayerCake(key=>value);

The constructor takes all the same arguments Data::Range::Compare::Stream::Iterator::Compare::Asc does along with the following optional arguments:

    factory_instance =>$obj
      # defines the object that implements the $obj->factory($start,$end,$data).
      # new ranges are constructed from the factory interfcae.  If a factory interface
      # is not created an instance of Data::Range::Compare::Stream is assumed.

    ignore_empty=>0|1 # default 0
      # when set to true all empty result sets are returned

    ignore_full=>0|1 # default 0
      # when set to true all full result sets are returned

    filter=>undef|code_ref
      # Default: undef  
      # When Defined: code_ref is used to filter results, code_ref->($result);
      #   if the code_ref returns false the result is ignored
      #   if the code_ref returns true the result will be used as the next valid result

=item * $compare->add_consolidator($iterator);

An $iterator object must implement one of the following iterator classes: Data::Range::Compare::Stream::Iterator::Consolidate, Data::Range::Compare::Stream::Iterator::Compare::Asc.  Result objects from $iterator->has_next must implement one of the following result objects: Data::Range::Compare::Stream::Iterator::Consolidate::Result, Data::Range::Compare::Stream::Iterator::Compare::Result.

=item * while($compare->has_next) { do something }

Returns true when the there are more ranges to consolidate.

=item * my $result=$compare->get_next;

if $compare->has_next returns true Returns a instance of Data::Range::Compare::Stream::Iterator::Compare::Result.

=item * my $count=$compare->get_column_count_human_readable;

Returns a human readable count of the columns in the comparison object.

=item * my $count=$compare->get_column_count;

Returns the last index id of the iterator column counts.

=item * my $range=$compare->get_current_row;

Returns the range object that will be used in the $compare->get_next call

=item * my $boolean=$compare->iterators_empty;

Returns false when all iterator objects in $compare are depleted

=item * my $result=$compare->get_next;

If $compare->has_next returns true Returns an instance of Data::Range::Compare::Stream::Iterator::Compare::Result.

=back

=head1 SEE ALSO

Data::Range::Compare::Stream::Iterator::Compare::Result

Data::Range::Compare::Stream::Iterator::Consolidate::Result

Data::Range::Compare::Stream::Iterator::Consolidate

Data::Range::Compare::Stream::Cookbook

=head1 AUTHOR

Michael Shipper

=head1 Source-Forge Project

As of version 0.001 the Project has been moved to Source-Forge.net

L<Data Range Compare|https://sourceforge.net/projects/data-range-comp/>
L<https://sourceforge.net/projects/data-range-comp/>

=head1 COPYRIGHT

Copyright 2011 Michael Shipper.  All rights reserved.

This library is free software; you can redistribute it and/or
modify it under the same terms as Perl itself.

=cut

