local-lib5/lib/perl5/Data/Stream/Bulk/Filter.pm

   1 #!/usr/bin/perl
   2
   3 package Data::Stream::Bulk::Filter;
   4 use Moose;
   5
   6 use Data::Stream::Bulk;
   7
   8 use namespace::clean -except => 'meta';
   9
  10 has filter => (
  11         isa => "CodeRef",
  12         reader => "filter_body",
  13         required => 1,
  14 );
  15
  16 has stream => (
  17         does => "Data::Stream::Bulk",
  18         is   => "ro",
  19         required => 1,
  20         handles  => [qw(is_done loaded)],
  21 );
  22
  23 with qw(Data::Stream::Bulk) => { excludes => 'loaded' };
  24
  25 sub next {
  26         my $self = shift;
  27
  28         local $_ = $self->stream->next;
  29         return $_ && ( $self->filter_body->($_) || [] );
  30 }
  31
  32 __PACKAGE__->meta->make_immutable;
  33
  34 __PACKAGE__
  35
  36 __END__
  37
  38 =pod
  39
  40 =head1 NAME
  41
  42 Data::Stream::Bulk::Filter - Streamed filtering (block oriented)
  43
  44 =head1 SYNOPSIS
  45
  46         use Data::Stream::Bulk::Filter;
  47
  48         Data::Stream::Bulk::Filter->new(
  49                 filter => sub { ... },
  50                 stream => $stream,
  51         );
  52
  53 =head1 DESCRIPTION
  54
  55 This class implements filtering of streams.
  56
  57 =head1 ATTRIBUTES
  58
  59 =over 4
  60
  61 =item filter
  62
  63 The code reference to apply to each block.
  64
  65 The block is passed to the filter both in C<$_> and as the first argument.
  66
  67 The return value should be an array reference. If no true value is returned the
  68 output stream does B<not> end, but instead an empty block is substituted (the
  69 parent stream controls when the stream is depleted).
  70
  71 =item stream
  72
  73 The stream to be filtered
  74
  75 =back
  76
  77 =head1 METHODS
  78
  79 =over 4
  80
  81 =item is_done
  82
  83 =item loaded
  84
  85 Delegated to C<stream>
  86
  87 =item next
  88
  89 Calls C<next> on C<stream> and applies C<filter> if a block was returned.
  90
  91 =back
  92
  93 =cut
  94
  95