Raw content of Bio::DasI # $Id: DasI.pm,v 1.15 2002/11/11 18:16:29 lapp Exp $ # # BioPerl module for Bio::DasI # # Cared for by Lincoln Stein <lstein@cshl.org> # # Copyright Lincoln Stein # # You may distribute this module under the same terms as perl itself # POD documentation - main docs before the code =head1 NAME Bio::DasI - DAS-style access to a feature database =head1 SYNOPSIS # Open up a feature database somehow... $db = Bio::DasI->new(@args); @segments = $db->segment(-name => 'NT_29921.4', -start => 1, -end => 1000000); # segments are Bio::Das::SegmentI - compliant objects # fetch a list of features @features = $db->features(-type=>['type1','type2','type3']); # invoke a callback over features $db->features(-type=>['type1','type2','type3'], -callback => sub { ... } ); $stream = $db->get_seq_stream(-type=>['type1','type2','type3']); while (my $feature = $stream->next_seq) { # each feature is a Bio::SeqFeatureI-compliant object } # get all feature types @types = $db->types; # count types %types = $db->types(-enumerate=>1); @feature = $db->get_feature_by_name($class=>$name); @feature = $db->get_feature_by_target($target_name); @feature = $db->get_feature_by_attribute($att1=>$value1,$att2=>$value2); $feature = $db->get_feature_by_id($id); $error = $db->error; =head1 DESCRIPTION Bio::DasI is a simplified alternative interface to sequence annotation databases used by the distributed annotation system (see L<Bio::Das>). In this scheme, the genome is represented as a series of features, a subset of which are named. Named features can be used as reference points for retrieving "segments" (see L<Bio::Das::SegmentI>), and these can, in turn, be used as the basis for exploring the genome further. In addition to a name, each feature has a "class", which is essentially a namespace qualifier and a "type", which describes what type of feature it is. Das uses the GO consortium's ontology of feature types, and so the type is actually an object of class Bio::Das::FeatureTypeI (see L<Bio::Das::FeatureTypeI>). Bio::DasI provides methods for interrogating the database for the types it contains and the counts of each type. =head1 FEEDBACK =head2 Mailing Lists User feedback is an integral part of the evolution of this and other Bioperl modules. Send your comments and suggestions preferably to one of the Bioperl mailing lists. Your participation is much appreciated. bioperl-l@bio.perl.org =head2 Reporting Bugs Report bugs to the Bioperl bug tracking system to help us keep track the bugs and their resolution. Bug reports can be submitted via email or the web: bioperl-bugs@bio.perl.org http://bugzilla.bioperl.org/ =head1 AUTHOR - Lincoln Stein Email lstein@cshl.org =head1 APPENDIX The rest of the documentation details each of the object methods. Internal methods are usually preceded with a _ =cut #' # Let the code begin... package Bio::DasI; use strict; use vars qw(@ISA); use Bio::Root::RootI; use Bio::Das::SegmentI; use Bio::SeqFeature::CollectionI; # Object preamble - inherits from Bio::Root::Root; @ISA = qw(Bio::Root::RootI Bio::SeqFeature::CollectionI); =head2 new Title : new Usage : Bio::DasI->new(@args) Function: Create new Bio::DasI object Returns : a Bio::DasI object Args : see below The new() method creates a new object. The argument list is either a single argument consisting of a connection string, or the following list of -name=E<gt>value arguments: Argument Description -------- ----------- -dsn Connection string for database -adaptor Name of an adaptor class to use when connecting -aggregator Array ref containing list of aggregators "semantic mappers" to apply to database -user Authentication username -pass Authentication password Implementors of DasI may add other arguments. =cut sub new {shift->throw_not_implemented} =head2 types Title : types Usage : $db->types(@args) Function: return list of feature types in database Returns : a list of Bio::Das::FeatureTypeI objects Args : see below This routine returns a list of feature types known to the database. It is also possible to find out how many times each feature occurs. Arguments are -option=E<gt>value pairs as follows: -enumerate if true, count the features The returned value will be a list of Bio::Das::FeatureTypeI objects (see L<Bio::Das::FeatureTypeI>. If -enumerate is true, then the function returns a hash (not a hash reference) in which the keys are the stringified versions of Bio::Das::FeatureTypeI and the values are the number of times each feature appears in the database. =cut sub types { shift->throw_not_implemented; } =head2 segment Title : segment Usage : $db->segment(@args); Function: create a segment object Returns : segment object(s) Args : see below This method generates a Bio::Das::SegmentI object (see L<Bio::Das::SegmentI>). The segment can be used to find overlapping features and the raw sequence. When making the segment() call, you specify the ID of a sequence landmark (e.g. an accession number, a clone or contig), and a positional range relative to the landmark. If no range is specified, then the entire region spanned by the landmark is used to generate the segment. Arguments are -option=E<gt>value pairs as follows: -name ID of the landmark sequence. -class A namespace qualifier. It is not necessary for the database to honor namespace qualifiers, but if it does, this is where the qualifier is indicated. -version Version number of the landmark. It is not necessary for the database to honor versions, but if it does, this is where the version is indicated. -start Start of the segment relative to landmark. Positions follow standard 1-based sequence rules. If not specified, defaults to the beginning of the landmark. -end End of the segment relative to the landmark. If not specified, defaults to the end of the landmark. The return value is a list of Bio::Das::SegmentI objects. If the method is called in a scalar context and there are no more than one segments that satisfy the request, then it is allowed to return the segment. Otherwise, the method must throw a "multiple segment exception". =cut #' sub segment { shift->throw_not_implemented } =head2 features Title : features Usage : $db->features(@args) Function: get all features, possibly filtered by type Returns : a list of Bio::SeqFeatureI objects Args : see below Status : public This routine will retrieve features in the database regardless of position. It can be used to return all features, or a subset based on their type Arguments are -option=E<gt>value pairs as follows: -types List of feature types to return. Argument is an array of Bio::Das::FeatureTypeI objects or a set of strings that can be converted into FeatureTypeI objects. -callback A callback to invoke on each feature. The subroutine will be passed each Bio::SeqFeatureI object in turn. -attributes A hash reference containing attributes to match. The -attributes argument is a hashref containing one or more attributes to match against: -attributes => { Gene => 'abc-1', Note => 'confirmed' } Attribute matching is simple exact string matching, and multiple attributes are ANDed together. See L<Bio::DB::ConstraintsI> for a more sophisticated take on this. If one provides a callback, it will be invoked on each feature in turn. If the callback returns a false value, iteration will be interrupted. When a callback is provided, the method returns undef. =cut sub features { shift->throw_not_implemented } =head2 get_feature_by_name Title : get_feature_by_name Usage : $db->get_feature_by_name(-class=>$class,-name=>$name) Function: fetch features by their name Returns : a list of Bio::SeqFeatureI objects Args : the class and name of the desired feature Status : public This method can be used to fetch named feature(s) from the database. The -class and -name arguments have the same meaning as in segment(), and the method also accepts the following short-cut forms: 1) one argument: the argument is treated as the feature name 2) two arguments: the arguments are treated as the class and name (note: this uses _rearrange() so the first argument must not begin with a hyphen or it will be interpreted as a named argument). This method may return zero, one, or several Bio::SeqFeatureI objects. The implementor may allow the name to contain wildcards, in which case standard C-shell glob semantics are expected. =cut sub get_feature_by_name { shift->throw_not_implemented(); } =head2 get_feature_by_target Title : get_feature_by_target Usage : $db->get_feature_by_target($class => $name) Function: fetch features by their similarity target Returns : a list of Bio::SeqFeatureI objects Args : the class and name of the desired feature Status : public This method can be used to fetch a named feature from the database based on its similarity hit. The arguments are the same as get_feature_by_name(). If this is not implemented, the interface defaults to using get_feature_by_name(). =cut sub get_feature_by_target { shift->get_feature_by_name(@_); } =head2 get_feature_by_id Title : get_feature_by_id Usage : $db->get_feature_by_target($id) Function: fetch a feature by its ID Returns : a Bio::SeqFeatureI objects Args : the ID of the feature Status : public If the database provides unique feature IDs, this can be used to retrieve a single feature from the database. If not overridden, this interface calls get_feature_by_name() and returns the first element. =cut sub get_feature_by_id { (shift->get_feature_by_name(@_))[0]; } =head2 get_feature_by_attribute Title : get_feature_by_attribute Usage : $db->get_feature_by_attribute(attribute1=>value1,attribute2=>value2) Function: fetch features by combinations of attribute values Returns : a list of Bio::SeqFeatureI objects Args : the class and name of the desired feature Status : public This method can be used to fetch a set of features from the database. Attributes are a list of name=E<gt>value pairs. They will be logically ANDed together. If an attribute value is an array reference, the list of values in the array is treated as an alternative set of values to be ORed together. =cut sub get_feature_by_attribute { shift->throw_not_implemented(); } =head2 search_notes Title : search_notes Usage : $db->search_notes($search_term,$max_results) Function: full-text search on features, ENSEMBL-style Returns : an array of [$name,$description,$score] Args : see below Status : public This routine performs a full-text search on feature attributes (which attributes depend on implementation) and returns a list of [$name,$description,$score], where $name is the feature ID, $description is a human-readable description such as a locus line, and $score is the match strength. Since this is a decidedly non-standard thing to do (but the generic genome browser uses it), the default method returns an empty list. You do not have to implement it. =cut sub search_notes { return } =head2 get_seq_stream Title : get_seq_stream Usage : $seqio = $db->get_seq_stream(@args) Function: Performs a query and returns an iterator over it Returns : a Bio::SeqIO stream capable of returning Bio::SeqFeatureI objects Args : As in features() Status : public This routine takes the same arguments as features(), but returns a Bio::SeqIO::Stream-compliant object. Use it like this: $stream = $db->get_seq_stream('exon'); while (my $exon = $stream->next_seq) { print $exon,"\n"; } NOTE: In the interface this method is aliased to get_feature_stream(), as the name is more descriptive. =cut sub get_seq_stream { shift->throw_not_implemented } sub get_feature_stream {shift->get_seq_stream(@_) } =head2 refclass Title : refclass Usage : $class = $db->refclass Function: returns the default class to use for segment() calls Returns : a string Args : none Status : public For data sources which use namespaces to distinguish reference sequence accessions, this returns the default namespace (or "class") to use. This interface defines a default of "Accession". =cut sub refclass { "Accession" } 1;