Bio::Das::FeatureIterator - Iterate over a set of Bio::Das::Features

Bio-Das documentation Contained in the Bio-Das distribution.

Index

Code Index:

NAME

Top

Bio::Das::FeatureIterator - Iterate over a set of Bio::Das::Features

SYNOPSIS

Top

 my $iterator =  $das->features(-dsn => ['http://www.wormbase.org/db/das/elegans',
					 'http://dev.wormbase.org/db/das/elegans'
				        ],
			        -segment => ['I:1,10000','II:1,10000'],
			        -category => 'transcription',
			        -iterator => 1,
			      );
 while (my $feature = $iterator=>next_seq) {
   print $feature,"\n";
 }

DESCRIPTION

Top

When the Bio::Das->features() method is called with the -iterator argument, the method will return an iterator over the features returned from the various data sources. Each feature can be returned by calling next_seq() iteratively until the method returns undef.

This is not as neat as it seems, because it works by creating all the features in advance and storing them in memory. For true pipelined access to the features, call features() with a callback subroutine.

AUTHOR

Top

Lincoln Stein <lstein@cshl.org>.

Copyright (c) 2001 Cold Spring Harbor Laboratory

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself. See DISCLAIMER.txt for disclaimers of warranty.

SEE ALSO

Top

Bio::Das::Request, Bio::Das::HTTP::Fetch, Bio::Das::Segment, Bio::Das::Type, Bio::Das::Stylesheet, Bio::Das::Source, Bio::RangeI

Bio-Das documentation Contained in the Bio-Das distribution. 
package Bio::Das::FeatureIterator;

use strict;
require Exporter;
use Carp 'croak';
use vars qw($VERSION);

$VERSION = '0.01';


sub new {
  my $class = shift;
  $class = ref($class) if ref($class);

  my $features = shift;
  return bless {responses=>$features},$class;
}

sub next_seq {
  my $self = shift;

  return shift @{$self->{next_result}}
    if $self->{next_result} && @{$self->{next_result}};

  while (1) {
    return unless @{$self->{responses}};
    my $response = shift @{$self->{responses}};
    if ($response->can('results')) {
      my @r = $response->results;
      $self->{next_result} = \@r;
      return shift @{$self->{next_result}} if @{$self->{next_result}};
    } else {
      return $response;
    }
  }
}


1;