Bio/Location/Split.pm

   1 #
   2 # BioPerl module for Bio::Location::Split
   3 # Please direct questions and support issues to <bioperl-l@bioperl.org>
   4 #
   5 # Cared for by Jason Stajich <jason@bioperl.org>
   6 #
   7 # Copyright Jason Stajich
   8 #
   9 # You may distribute this module under the same terms as perl itself
  10 # POD documentation - main docs before the code
  11
  12 =head1 NAME
  13
  14 Bio::Location::Split - Implementation of a Location on a Sequence
  15 which has multiple locations (start/end points)
  16
  17 =head1 SYNOPSIS
  18
  19     use Bio::Location::Split;
  20
  21     my $splitlocation = Bio::Location::Split->new();
  22     $splitlocation->add_sub_Location(Bio::Location::Simple->new(-start=>1,
  23                                                                -end=>30,
  24                                                                -strand=>1));
  25     $splitlocation->add_sub_Location(Bio::Location::Simple->new(-start=>50,
  26                                                                -end=>61,
  27                                                                -strand=>1));
  28     my @sublocs = $splitlocation->sub_Location();
  29
  30     my $count = 1;
  31     # print the start/end points of the sub locations
  32     foreach my $location ( sort { $a->start <=> $b->start }
  33                            @sublocs ) {
  34         printf "sub feature %d [%d..%d]\n",
  35                $count, $location->start,$location->end, "\n";
  36         $count++;
  37     }
  38
  39 =head1 DESCRIPTION
  40
  41 This implementation handles locations which span more than one
  42 start/end location, or and/or lie on different sequences, and can
  43 work with split locations that depend on the specific order of the
  44 sublocations ('join') or don't have a specific order but represent
  45 a feature spanning noncontiguous sublocations ('order', 'bond').
  46
  47 Note that the order in which sublocations are added may be very important,
  48 depending on the specific split location type.  For instance, a 'join'
  49 must have the sublocations added in the order that one expects to
  50 join the sublocations, whereas all other types are sorted based on the
  51 sequence location.
  52
  53 =head1 FEEDBACK
  54
  55 User feedback is an integral part of the evolution of this and other
  56 Bioperl modules. Send your comments and suggestions preferably to one
  57 of the Bioperl mailing lists.  Your participation is much appreciated.
  58
  59   bioperl-l@bioperl.org                  - General discussion
  60   http://bioperl.org/wiki/Mailing_lists  - About the mailing lists
  61
  62 =head2 Support
  63
  64 Please direct usage questions or support issues to the mailing list:
  65
  66 I<bioperl-l@bioperl.org>
  67
  68 rather than to the module maintainer directly. Many experienced and
  69 reponsive experts will be able look at the problem and quickly
  70 address it. Please include a thorough description of the problem
  71 with code and data examples if at all possible.
  72
  73 =head2 Reporting Bugs
  74
  75 Report bugs to the Bioperl bug tracking system to help us keep track
  76 the bugs and their resolution.  Bug reports can be submitted via the
  77 web:
  78
  79   https://github.com/bioperl/bioperl-live/issues
  80
  81 =head1 AUTHOR - Jason Stajich
  82
  83 Email jason-AT-bioperl_DOT_org
  84
  85 =head1 APPENDIX
  86
  87 The rest of the documentation details each of the object
  88 methods. Internal methods are usually preceded with a _
  89
  90 =cut
  91
  92 # Let the code begin...
  93
  94 package Bio::Location::Split;
  95
  96 # as defined by BSANE 0.03
  97 our @CORBALOCATIONOPERATOR = ('NONE','JOIN', undef, 'ORDER');;
  98
  99 use Bio::Root::Root;
 100
 101 use base qw(Bio::Location::Atomic Bio::Location::SplitLocationI);
 102
 103 sub new {
 104     my ($class, @args) = @_;
 105     my $self = $class->SUPER::new(@args);
 106     # initialize
 107     $self->{'_sublocations'} = [];
 108     my ( $type, $seqid, $locations ) =
 109         $self->_rearrange([qw(SPLITTYPE
 110                               SEQ_ID
 111                               LOCATIONS
 112                               )], @args);
 113     if( defined $locations && ref($locations) =~ /array/i ) {
 114         $self->add_sub_Location(@$locations);
 115     }
 116     $seqid  && $self->seq_id($seqid);
 117     $type ||= 'JOIN';
 118     $type = lc ($type);
 119     $self->splittype($type);
 120     return $self;
 121 }
 122
 123 =head2 each_Location
 124
 125  Title   : each_Location
 126  Usage   : @locations = $locObject->each_Location($order);
 127  Function: Conserved function call across Location:: modules - will
 128            return an array containing the component Location(s) in
 129            that object, regardless if the calling object is itself a
 130            single location or one containing sublocations.
 131  Returns : an array of Bio::LocationI implementing objects
 132  Args    : Optional sort order to be passed to sub_Location()
 133
 134 =cut
 135
 136 sub each_Location {
 137     my ($self, $order) = @_;
 138     my @locs = ();
 139     foreach my $subloc ($self->sub_Location($order)) {
 140         # Recursively check to get hierarchical split locations:
 141         push @locs, $subloc->each_Location($order);
 142     }
 143     return @locs;
 144 }
 145
 146 =head2 sub_Location
 147
 148  Title   : sub_Location
 149  Usage   : @sublocs = $splitloc->sub_Location();
 150  Function: Returns the array of sublocations making up this compound (split)
 151            location. Those sublocations referring to the same sequence as
 152            the root split location will be sorted by start position (forward
 153            sort) or end position (reverse sort) and come first (before
 154            those on other sequences).
 155
 156            The sort order can be optionally specified or suppressed by the
 157            value of the first argument. The default is no sort.
 158
 159  Returns : an array of Bio::LocationI implementing objects
 160  Args    : Optionally 1, 0, or -1 for specifying a forward, no, or reverse
 161            sort order
 162
 163 =cut
 164
 165 sub sub_Location {
 166     my ($self, $order) = @_;
 167     $order = 0 unless defined $order;
 168     if( defined($order) && ($order !~ /^-?\d+$/) ) {
 169         $self->throw("value $order passed in to sub_Location is $order, an invalid value");
 170     }
 171     $order = 1 if($order > 1);
 172     $order = -1 if($order < -1);
 173     my @sublocs = defined $self->{'_sublocations'} ? @{$self->{'_sublocations'}} : ();
 174
 175     # return the array if no ordering requested
 176     return @sublocs if( ($order == 0) || (! @sublocs) );
 177
 178     # sort those locations that are on the same sequence as the top (`master')
 179     # if the top seq is undefined, we take the first defined in a sublocation
 180     my $seqid = $self->seq_id();
 181     my $i = 0;
 182     while((! defined($seqid)) && ($i <= $#sublocs)) {
 183                 $seqid = $sublocs[$i++]->seq_id();
 184     }
 185     if((! $self->seq_id()) && $seqid) {
 186                 $self->warn("sorted sublocation array requested but ".
 187                                 "root location doesn't define seq_id ".
 188                                 "(at least one sublocation does!)");
 189     }
 190     my @locs = ($seqid ?
 191                 grep { $_->seq_id() eq $seqid; } @sublocs :
 192                 @sublocs);
 193     if(@locs) {
 194                 if($order == 1) {
 195                         # Schwartzian transforms for performance boost
 196                         @locs = map { $_->[0] }
 197                         sort {
 198                                 (defined $a && defined $b) ? $a->[1] <=> $b->[1] :
 199                 $a                         ?  -1                 : 1
 200                                 }
 201                         map {
 202                                 [$_, (defined $_->start ? $_->start : $_->end)]
 203                                 } @locs;;
 204                 } else { # $order == -1
 205                         @locs = map { $_->[0]}
 206                         sort {
 207                                 (defined $a && defined $b) ? $b->[1] <=> $a->[1] :
 208                                 $a                         ? -1                  : 1
 209                                 }
 210                         map {
 211                                 [$_, (defined $_->end ? $_->end : $_->start)]
 212                                 } @locs;
 213                 }
 214     }
 215     # push the rest unsorted
 216     if($seqid) {
 217                 push(@locs, grep { $_->seq_id() ne $seqid; } @sublocs);
 218     }
 219     # done!
 220
 221     return @locs;
 222 }
 223
 224 =head2 add_sub_Location
 225
 226  Title   : add_sub_Location
 227  Usage   : $splitloc->add_sub_Location(@locationIobjs);
 228  Function: add an additional sublocation
 229  Returns : number of current sub locations
 230  Args    : list of Bio::LocationI implementing object(s) to add
 231
 232 =cut
 233
 234 sub add_sub_Location {
 235     my ($self,@args) = @_;
 236     my @locs;
 237     foreach my $loc ( @args ) {
 238         if( !ref($loc) || ! $loc->isa('Bio::LocationI') ) {
 239             $self->throw("Trying to add $loc as a sub Location but it doesn't implement Bio::LocationI!");
 240             next;
 241         }
 242         push @{$self->{'_sublocations'}}, $loc;
 243     }
 244
 245     return scalar @{$self->{'_sublocations'}};
 246 }
 247
 248 =head2 splittype
 249
 250   Title   : splittype
 251   Usage   : $splittype = $location->splittype();
 252   Function: get/set the split splittype
 253   Returns : the splittype of split feature (join, order)
 254   Args    : splittype to set
 255
 256 =cut
 257
 258 sub splittype {
 259     my ($self, $value) = @_;
 260     if( defined $value || ! defined $self->{'_splittype'} ) {
 261         $value = 'JOIN' unless( defined $value );
 262         $self->{'_splittype'} = uc ($value);
 263     }
 264     return $self->{'_splittype'};
 265 }
 266
 267 =head2 is_single_sequence
 268
 269   Title   : is_single_sequence
 270   Usage   : if($splitloc->is_single_sequence()) {
 271                 print "Location object $splitloc is split ".
 272                       "but only across a single sequence\n";
 273             }
 274   Function: Determine whether this location is split across a single or
 275             multiple sequences.
 276
 277             This implementation ignores (sub-)locations that do not define
 278             seq_id(). The same holds true for the root location.
 279
 280   Returns : TRUE if all sublocations lie on the same sequence as the root
 281             location (feature), and FALSE otherwise.
 282   Args    : none
 283
 284 =cut
 285
 286 sub is_single_sequence {
 287     my ($self) = @_;
 288
 289     my $seqid = $self->seq_id();
 290     foreach my $loc ($self->sub_Location(0)) {
 291         $seqid = $loc->seq_id() if(! $seqid);
 292         if(defined($loc->seq_id()) && ($loc->seq_id() ne $seqid)) {
 293             return 0;
 294         }
 295     }
 296     return 1;
 297 }
 298
 299 =head2 guide_strand
 300
 301   Title   : guide_strand
 302   Usage   : $str = $loc->guide_strand();
 303   Function: Get/Set the guide strand.  Of use only if the split type is
 304             a 'join' (this helps determine the order of sublocation
 305                         retrieval)
 306   Returns : value of guide strand (1, -1, or undef)
 307   Args    : new value (-1 or 1, optional)
 308
 309 =cut
 310
 311 sub guide_strand {
 312     my $self = shift;
 313     return $self->{'strand'} = shift if @_;
 314
 315     # Sublocations strand values consistency check to set Guide Strand
 316     my @subloc_strands;
 317     foreach my $loc ($self->sub_Location(0)) {
 318         push @subloc_strands, $loc->strand || 1;
 319     }
 320     if ($self->isa('Bio::Location::SplitLocationI')) {
 321         my $identical   = 0;
 322         my $first_value = $subloc_strands[0];
 323         foreach my $strand (@subloc_strands) {
 324             $identical++ if ($strand == $first_value);
 325         }
 326
 327         if ($identical == scalar @subloc_strands) {
 328             $self->{'strand'} = $first_value;
 329         }
 330         else {
 331             $self->{'strand'} = undef;
 332         }
 333     }
 334     return $self->{'strand'};
 335 }
 336
 337 =head1 LocationI methods
 338
 339 =head2 strand
 340
 341  Title   : strand
 342  Usage   : $obj->strand($newval)
 343  Function: For SplitLocations, setting the strand of the container
 344            (this object) is a short-cut for setting the strand of all
 345            sublocations.
 346
 347            In get-mode, checks if no sub-location is remote, and if
 348            all have the same strand. If so, it returns that shared
 349            strand value. Otherwise it returns undef.
 350
 351  Example :
 352  Returns : on get, value of strand if identical between sublocations
 353            (-1, 1, or undef)
 354  Args    : new value (-1 or 1, optional)
 355
 356
 357 =cut
 358
 359 sub strand{
 360     my ($self,$value) = @_;
 361     if( defined $value) {
 362         $self->{'strand'} = $value;
 363         # propagate to all sublocs
 364         foreach my $loc ($self->sub_Location(0)) {
 365             $loc->strand($value);
 366         }
 367     }
 368     else {
 369         my ($strand, $lstrand);
 370         foreach my $loc ($self->sub_Location(0)) {
 371             # we give up upon any location that doesn't have
 372             # the strand specified, or has a differing one set than
 373             # previously seen.
 374             # calling strand() is potentially expensive if the subloc
 375             # is also a split location, so we cache it
 376             $lstrand = $loc->strand();
 377             if (  ! $lstrand
 378                 or ($strand and ($strand != $lstrand))
 379                 ) {
 380                 $strand = undef;
 381                 last;
 382             }
 383             elsif (! $strand) {
 384                 $strand = $lstrand;
 385             }
 386         }
 387         return $strand;
 388     }
 389 }
 390
 391 =head2 flip_strand
 392
 393   Title   : flip_strand
 394   Usage   : $location->flip_strand();
 395   Function: Flip-flop a strand to the opposite.  Also sets Split strand
 396             to be consistent with the sublocation strands
 397             (1, -1 or undef for mixed strand values)
 398   Returns : None
 399   Args    : None
 400
 401 =cut
 402
 403 sub flip_strand {
 404     my $self = shift;
 405     my @sublocs;
 406     my @subloc_strands;
 407
 408     for my $loc ( $self->sub_Location(0) ) {
 409         # Atomic "flip_strand" now initialize strand if necessary
 410         my $new_strand = $loc->flip_strand;
 411
 412         # Store strand values for later consistency check
 413         push @sublocs, $loc;
 414         push @subloc_strands, $new_strand;
 415     }
 416
 417     # Sublocations strand values consistency check to set Guide Strand
 418     if ($self->isa('Bio::Location::SplitLocationI')) {
 419         my $identical   = 0;
 420         my $first_value = $subloc_strands[0];
 421         foreach my $strand (@subloc_strands) {
 422             $identical++ if ($strand == $first_value);
 423         }
 424
 425         if ($identical == scalar @subloc_strands) {
 426             $self->guide_strand($first_value);
 427         }
 428         else {
 429             # Mixed strand values, must reverse the sublocations order
 430             $self->guide_strand(undef);
 431             @{ $self->{_sublocations} } = reverse @sublocs;
 432         }
 433     }
 434 }
 435
 436 =head2 start
 437
 438   Title   : start
 439   Usage   : $start = $location->start();
 440   Function: get the starting point of the first (sorted) sublocation
 441   Returns : integer
 442   Args    : none
 443
 444 =cut
 445
 446 sub start {
 447     my ($self,$value) = @_;
 448     if( defined $value ) {
 449         $self->throw(  "Trying to set the starting point of a split location, "
 450                      . "that is not possible, try manipulating the sub Locations");
 451     }
 452     return $self->SUPER::start();
 453 }
 454
 455 =head2 end
 456
 457   Title   : end
 458   Usage   : $end = $location->end();
 459   Function: get the ending point of the last (sorted) sublocation
 460   Returns : integer
 461   Args    : none
 462
 463 =cut
 464
 465 sub end {
 466     my ($self,$value) = @_;
 467     if( defined $value ) {
 468         $self->throw(  "Trying to set the ending point of a split location, "
 469                      . "that is not possible, try manipulating the sub Locations");
 470     }
 471     return $self->SUPER::end();
 472 }
 473
 474 =head2 min_start
 475
 476   Title   : min_start
 477   Usage   : $min_start = $location->min_start();
 478   Function: get the minimum starting point
 479   Returns : the minimum starting point from the contained sublocations
 480   Args    : none
 481
 482 =cut
 483
 484 sub min_start {
 485     my ($self, $value) = @_;
 486
 487     if( defined $value ) {
 488         $self->throw(  "Trying to set the minimum starting point of a split "
 489                      . "location, that is not possible, try manipulating the sub Locations");
 490     }
 491     # No sort by default because it breaks circular cut by origin features
 492     # (like "join(2006035..2007700,1..257)"). Sorting is user responsability.
 493     # Assume Start to be 1st segment start and End to be last segment End.
 494     my @locs = $self->sub_Location(0);
 495     return ( @locs ) ? $locs[0]->min_start : undef;
 496 }
 497
 498 =head2 max_start
 499
 500   Title   : max_start
 501   Usage   : my $maxstart = $location->max_start();
 502   Function: Get maximum starting location of feature startpoint
 503   Returns : integer or undef if no maximum starting point.
 504   Args    : none
 505
 506 =cut
 507
 508 sub max_start {
 509     my ($self,$value) = @_;
 510
 511     if( defined $value ) {
 512         $self->throw(  "Trying to set the maximum starting point of a split "
 513                      . "location, that is not possible, try manipulating the sub Locations");
 514     }
 515     # No sort by default because it breaks circular cut by origin features
 516     # (like "join(2006035..2007700,1..257)"). Sorting is user responsability.
 517     # Assume Start to be 1st segment start and End to be last segment End.
 518     my @locs = $self->sub_Location(0);
 519     return ( @locs ) ? $locs[0]->max_start : undef;
 520 }
 521
 522 =head2 start_pos_type
 523
 524   Title   : start_pos_type
 525   Usage   : my $start_pos_type = $location->start_pos_type();
 526   Function: Get start position type (ie <,>, ^)
 527   Returns : type of position coded as text
 528             ('BEFORE', 'AFTER', 'EXACT','WITHIN', 'BETWEEN')
 529   Args    : none
 530
 531 =cut
 532
 533 sub start_pos_type {
 534     my ($self,$value) = @_;
 535
 536     if( defined $value ) {
 537         $self->throw(  "Trying to set the start_pos_type of a split location, "
 538                      . "that is not possible, try manipulating the sub Locations");
 539     }
 540     # No sort by default because it breaks circular cut by origin features
 541     # (like "join(2006035..2007700,1..257)"). Sorting is user responsability.
 542     # Assume Start to be 1st segment start and End to be last segment End.
 543     my @locs = $self->sub_Location(0);
 544     return ( @locs ) ? $locs[0]->start_pos_type : undef;
 545 }
 546
 547 =head2 min_end
 548
 549   Title   : min_end
 550   Usage   : my $minend = $location->min_end();
 551   Function: Get minimum ending location of feature endpoint
 552   Returns : integer or undef if no minimum ending point.
 553   Args    : none
 554
 555 =cut
 556
 557 sub min_end {
 558     my ($self,$value) = @_;
 559
 560     if( defined $value ) {
 561         $self->throw(  "Trying to set the minimum end point of a split location, "
 562                      . "that is not possible, try manipulating the sub Locations");
 563     }
 564     # No sort by default because it breaks circular cut by origin features
 565     # (like "join(2006035..2007700,1..257)"). Sorting is user responsability.
 566     # Assume Start to be 1st segment start and End to be last segment End.
 567     my @locs = $self->sub_Location(0);
 568
 569     # Return the End corresponding to the same sequence as the top ('master')
 570     # if the top seq is undefined, take the first defined in a sublocation.
 571     # Example: for "join(1..100,J00194.1:100..202)", End would be 100
 572     my $seqid = $self->seq_id;
 573     my $i = 0;
 574     while (not defined $seqid and $i <= $#locs) {
 575         $seqid = $locs[$i++]->seq_id;
 576     }
 577
 578     my @same_id_locs = ($seqid ? grep { $_->seq_id eq $seqid } @locs
 579                      :           @locs);
 580     # If there is a $seqid but no sublocations have the same id,
 581     # try with the first id found in the sublocations instead,
 582     # and if that fails return the last segment value
 583     if (@locs and not @same_id_locs) {
 584         my $first_id;
 585         while (not defined $first_id and $i <= $#locs) {
 586             $first_id = $locs[$i++]->seq_id;
 587         }
 588         @same_id_locs = ($first_id ? grep { $_->seq_id eq $first_id } @locs
 589                       :              @locs);
 590     }
 591     return ( @same_id_locs ) ? $same_id_locs[-1]->min_end : undef;
 592 }
 593
 594 =head2 max_end
 595
 596   Title   : max_end
 597   Usage   : my $maxend = $location->max_end();
 598   Function: Get maximum ending location of feature endpoint
 599   Returns : integer or undef if no maximum ending point.
 600   Args    : none
 601
 602 =cut
 603
 604 sub max_end {
 605     my ($self,$value) = @_;
 606
 607     if( defined $value ) {
 608         $self->throw(  "Trying to set the maximum end point of a split location, "
 609                      ."that is not possible, try manipulating the sub Locations");
 610     }
 611     # No sort by default because it breaks circular cut by origin features
 612     # (like "join(2006035..2007700,1..257)"). Sorting is user responsability.
 613     # Assume Start to be 1st segment start and End to be last segment End.
 614     my @locs = $self->sub_Location(0);
 615
 616     # Return the End corresponding to the same sequence as the top ('master')
 617     # if the top seq is undefined, take the first defined in a sublocation.
 618     # Example: for "join(1..100,J00194.1:100..202)", End would be 100
 619     my $seqid = $self->seq_id;
 620     my $i = 0;
 621     while (not defined $seqid and $i <= $#locs) {
 622         $seqid = $locs[$i++]->seq_id;
 623     }
 624
 625     my @same_id_locs = ($seqid ? grep { $_->seq_id eq $seqid } @locs
 626                      :           @locs);
 627     # If there is a $seqid but no sublocations have the same id,
 628     # try with the first id found in the sublocations instead,
 629     # and if that fails return the last segment value
 630     if (@locs and not @same_id_locs) {
 631         my $first_id;
 632         while (not defined $first_id and $i <= $#locs) {
 633             $first_id = $locs[$i++]->seq_id;
 634         }
 635         @same_id_locs = ($first_id ? grep { $_->seq_id eq $first_id } @locs
 636                       :              @locs);
 637     }
 638     return ( @same_id_locs ) ? $same_id_locs[-1]->max_end : undef;
 639 }
 640
 641 =head2 end_pos_type
 642
 643   Title   : end_pos_type
 644   Usage   : my $end_pos_type = $location->end_pos_type();
 645   Function: Get end position type (ie <,>, ^)
 646   Returns : type of position coded as text
 647             ('BEFORE', 'AFTER', 'EXACT','WITHIN', 'BETWEEN')
 648   Args    : none
 649
 650 =cut
 651
 652 sub end_pos_type {
 653     my ($self,$value) = @_;
 654
 655     if( defined $value ) {
 656         $self->throw(  "Trying to set end_pos_type of a split location, "
 657                      . "that is not possible, try manipulating the sub Locations");
 658     }
 659     # No sort by default because it breaks circular cut by origin features
 660     # (like "join(2006035..2007700,1..257)"). Sorting is user responsability.
 661     # Assume Start to be 1st segment start and End to be last segment End.
 662     my @locs = $self->sub_Location(0);
 663
 664     # Return the End corresponding to the same sequence as the top ('master')
 665     # if the top seq is undefined, take the first defined in a sublocation.
 666     # Example: for "join(1..>100,J00194.1:100..202)", End pos type would be 'AFTER'
 667     my $seqid = $self->seq_id;
 668     my $i = 0;
 669     while (not defined $seqid and $i <= $#locs) {
 670         $seqid = $locs[$i++]->seq_id;
 671     }
 672
 673     my @same_id_locs = ($seqid ? grep { $_->seq_id eq $seqid } @locs
 674                      :           @locs);
 675     # If there is a $seqid but no sublocations have the same id,
 676     # try with the first id found in the sublocations instead,
 677     # and if that fails return the last segment value
 678     if (@locs and not @same_id_locs) {
 679         my $first_id;
 680         while (not defined $first_id and $i <= $#locs) {
 681             $first_id = $locs[$i++]->seq_id;
 682         }
 683         @same_id_locs = ($first_id ? grep { $_->seq_id eq $first_id } @locs
 684                       :              @locs);
 685     }
 686     return ( @same_id_locs ) ? $same_id_locs[-1]->end_pos_type : undef;
 687 }
 688
 689 =head2 length
 690
 691  Title   : length
 692  Usage   : $len = $loc->length();
 693  Function: get the length in the coordinate space this location spans
 694  Example :
 695  Returns : an integer
 696  Args    : none
 697
 698 =cut
 699
 700 sub length {
 701     my ($self) = @_;
 702     my $length = 0;
 703     # Mixed strand values means transplicing (where exons can even
 704     # be in different chromosomes), so in that case only give the sum
 705     # of the lengths of the individual segments
 706     if (! defined $self->guide_strand) {
 707         for my $loc ( $self->sub_Location(0) ) {
 708             $length += abs($loc->end - $loc->start) + 1;
 709         }
 710     }
 711     else {
 712         my @sublocs = $self->sub_Location(0);
 713         my $start   = $sublocs[0]->start;
 714         my $end     = $sublocs[-1]->end;
 715
 716         # If Start > ·End, its a possible case of cut by origin
 717         # location in circular sequences (e.g "join(16..20,1..2)")
 718         if ($start > $end) {
 719             # Figure out which segments are located before
 720             # and which are located after coordinate 1
 721             # (END_SEQ - 1 - START_SEQ)
 722             my @end_seq_segments;
 723             my @start_seq_segments;
 724             my $switch = 0;
 725             foreach my $subloc (@sublocs) {
 726                 if ($switch == 0) {
 727                     if ($subloc->start == 1) {
 728                         $switch = 1;
 729                         push @start_seq_segments, $subloc;
 730                     }
 731                     else {
 732                         push @end_seq_segments, $subloc;
 733                     }
 734                 }
 735                 else {
 736                     push @start_seq_segments, $subloc;
 737                 }
 738             }
 739
 740             # If its a cut by origin location, sum the whole length of each group
 741             if (scalar @end_seq_segments > 0 and @start_seq_segments > 0) {
 742                 my $end_segments_length   = abs(  $end_seq_segments[0]->start
 743                                                 - $end_seq_segments[-1]->end)
 744                                                 + 1;
 745                 my $start_segments_length = abs(  $start_seq_segments[0]->start
 746                                                 - $start_seq_segments[-1]->end)
 747                                                 + 1;
 748                 $length = $end_segments_length + $start_segments_length;
 749             }
 750         }
 751         else {
 752             $length = $end - $start + 1;
 753         }
 754     }
 755
 756     # If for some reason nothing worked, fall back to previous behaviour
 757     if ($length == 0) {
 758         $length = abs($self->end - $self->start) + 1
 759     }
 760
 761     return $length;
 762 }
 763
 764 =head2 seq_id
 765
 766   Title   : seq_id
 767   Usage   : my $seqid = $location->seq_id();
 768   Function: Get/Set seq_id that location refers to
 769
 770             We override this here in order to propagate to all sublocations
 771             which are not remote (provided this root is not remote either)
 772   Returns : seq_id
 773   Args    : [optional] seq_id value to set
 774
 775
 776 =cut
 777
 778 sub seq_id {
 779     my $self = shift;
 780
 781     if(@_ && !$self->is_remote()) {
 782         foreach my $subloc ($self->sub_Location(0)) {
 783             $subloc->seq_id(@_) if !$subloc->is_remote();
 784         }
 785     }
 786     return $self->SUPER::seq_id(@_);
 787 }
 788
 789 =head2 coordinate_policy
 790
 791   Title   : coordinate_policy
 792   Usage   : $policy = $location->coordinate_policy();
 793             $location->coordinate_policy($mypolicy); # set may not be possible
 794   Function: Get the coordinate computing policy employed by this object.
 795
 796             See Bio::Location::CoordinatePolicyI for documentation about
 797             the policy object and its use.
 798
 799             The interface *does not* require implementing classes to accept
 800             setting of a different policy. The implementation provided here
 801             does, however, allow to do so.
 802
 803             Implementors of this interface are expected to initialize every
 804             new instance with a CoordinatePolicyI object. The implementation
 805             provided here will return a default policy object if none has
 806             been set yet. To change this default policy object call this
 807             method as a class method with an appropriate argument. Note that
 808             in this case only subsequently created Location objects will be
 809             affected.
 810
 811   Returns : A Bio::Location::CoordinatePolicyI implementing object.
 812   Args    : On set, a Bio::Location::CoordinatePolicyI implementing object.
 813
 814 =head2 to_FTstring
 815
 816   Title   : to_FTstring
 817   Usage   : my $locstr = $location->to_FTstring()
 818   Function: returns the FeatureTable string of this location
 819   Returns : string
 820   Args    : none
 821
 822 =cut
 823
 824 sub to_FTstring {
 825     my ($self) = @_;
 826     my @strs;
 827         my $strand = $self->strand() || 0;
 828         my $stype = lc($self->splittype());
 829
 830     if( $strand < 0 ) {
 831                 $self->flip_strand; # this will recursively set the strand
 832                                                         # to +1 for all the sub locations
 833     }
 834
 835     foreach my $loc ( $self->sub_Location(0) ) {
 836                 $loc->verbose($self->verbose);
 837                 my $str = $loc->to_FTstring();
 838                 # we only append the remote seq_id if it hasn't been done already
 839                 # by the sub-location (which it should if it knows it's remote)
 840                 # (and of course only if it's necessary)
 841                 if( (! $loc->is_remote) &&
 842                         defined($self->seq_id) && defined($loc->seq_id) &&
 843                         ($loc->seq_id ne $self->seq_id) ) {
 844                         $str = sprintf("%s:%s", $loc->seq_id, $str);
 845                 }
 846                 push @strs, $str;
 847         }
 848         $self->flip_strand if $strand < 0;
 849         my $str;
 850         if( @strs == 1 ) {
 851                 ($str) = @strs;
 852         } elsif( @strs == 0 ) {
 853                 $self->warn("no Sublocations for this splitloc, so not returning anything\n");
 854         } else {
 855                 $str = sprintf("%s(%s)",lc $self->splittype, join(",", @strs));
 856         }
 857         if( $strand < 0 ) {  # wrap this in a complement if it was unrolled
 858                 $str = sprintf("%s(%s)",'complement',$str);
 859         }
 860
 861     return $str;
 862 }
 863
 864 =head2 valid_Location
 865
 866  Title   : valid_Location
 867  Usage   : if ($location->valid_location) {...};
 868  Function: boolean method to determine whether location is considered valid
 869            (has minimum requirements for Simple implementation)
 870  Returns : Boolean value: true if location is valid, false otherwise
 871  Args    : none
 872
 873 =cut
 874
 875 # we'll probably need to override the RangeI methods since our locations will
 876 # not be contiguous.
 877
 878 1;