Summary

Bio::DB::InMemoryCache - Abstract interface for a sequence database

Package variables

Included modules

Inherit

Bio::DB::SeqI Bio::Root::Root

Synopsis

  $cachedb = Bio::DB::InMemoryCache->new( -seqdb => $real_db,
                                          -number => 1000);

  #
  # get a database object somehow using a concrete class
  #

  $seq = $cachedb->get_Seq_by_id('ROA1_HUMAN');

  #
  # $seq is a Bio::Seq object
  #

Description

This is a memory cache system which saves the objects returned by Bio::DB::RandomAccessI in
memory to a hard limit of sequences.

Methods

Methods description

 Title   : get_Seq_by_id
 Usage   : $seq = $db->get_Seq_by_id('ROA1_HUMAN')
 Function: Gets a Bio::Seq object by its name
 Returns : a Bio::Seq object
 Args    : the id (as a string) of a sequence
 Throws  : "id does not exist" exception

 Title   : get_Seq_by_acc
 Usage   : $seq = $db->get_Seq_by_acc('X77802');
 Function: Gets a Bio::Seq object by accession number
 Returns : A Bio::Seq object
 Args    : accession number (as a string)
 Throws  : "acc does not exist" exception

 Title   : get_Seq_by_version
 Usage   : $seq = $db->get_Seq_by_version('X77802.1');
 Function: Gets a Bio::Seq object by sequence version
 Returns : A Bio::Seq object
 Args    : accession.version (as a string)
 Throws  : "acc.version does not exist" exception

Methods code

sub new {

    my ($class,@args) = @_;

    my $self = Bio::Root::Root->new();
    bless $self,$class;

    my ($seqdb,$number,$agr) = $self->_rearrange([qw(SEQDB NUMBER AGRESSION)],@args);

    if( !defined $seqdb || !ref $seqdb || !$seqdb->isa('Bio::DB::RandomAccessI') ) {
       $self->throw("Must be a randomaccess database not a [$seqdb]");
    }
    if( !defined $number ) {
        $number = 1000;
    }
    
    $self->seqdb($seqdb);
    $self->number($number);
    $self->agr($agr);

    # we consider acc as the primary id here
    $self->{'_cache_number_hash'} = {};
    $self->{'_cache_id_hash'}     = {};
    $self->{'_cache_acc_hash'}    = {};
    $self->{'_cache_number'}      = 1;

    return $self;

}

sub get_Seq_by_id {

   my ($self,$id) = @_;

   if( defined $self->{'_cache_id_hash'}->{$id} ) {
     my $acc = $self->{'_cache_id_hash'}->{$id};
     my $seq = $self->{'_cache_acc_hash'}->{$acc};
     $self->{'_cache_number_hash'}->{$seq->accession} = $self->{'_cache_number'}++;
     return $seq;
   } else {
     return $self->_load_Seq('id',$id);
   }

}

sub get_Seq_by_acc {

   my ($self,$acc) = @_;

   #print STDERR "In cache get for $acc\n";
   if( defined $self->{'_cache_acc_hash'}->{$acc} ) {
       #print STDERR "Returning cached $acc\n";
       my $seq = $self->{'_cache_acc_hash'}->{$acc};
       $self->{'_cache_number_hash'}->{$seq->accession} = $self->{'_cache_number'}++;
       return $seq;
   } else {
     return $self->_load_Seq('acc',$acc);
   }

}

sub number {

    my ($self, $number) = @_;
    if ($number) {
        $self->{'number'} = $number;
    } else {
        return $self->{'number'};
    }

}

sub seqdb {

    my ($self, $seqdb) = @_;
    if ($seqdb) {
        $self->{'seqdb'} = $seqdb;
    } else {
        return $self->{'seqdb'};
    }

}

sub agr {

    my ($self, $agr) = @_;
    if ($agr) {
        $self->{'agr'} = $agr;
    } else {
        return $self->{'agr'};
    }

}

sub _load_Seq {

  my ($self,$type,$id) = @_;

  my $seq;

  if( $type eq 'id') {
    $seq = $self->seqdb->get_Seq_by_id($id);
  }elsif ( $type eq 'acc' ) {
    $seq = $self->seqdb->get_Seq_by_acc($id);
  } else {
    $self->throw("Bad internal error. Don't understand $type");
  }

  if( $self->agr() ) {
      #print STDERR "Pulling out into memory\n";
      my $newseq = Bio::Seq->new( -display_id => $seq->display_id,
				  -accession_number  => $seq->accession,
				  -seq        => $seq->seq,
				  -desc       => $seq->desc,
				  );
      if( $self->agr() == 1 ) {
	  foreach my $sf ( $seq->top_SeqFeatures() ) {
	      $newseq->add_SeqFeature($sf);
	  }
	  
	  $newseq->annotation($seq->annotation);
      }
      $seq = $newseq;
  }

  if( $self->_number_free < 1 ) {
    # remove the latest thing from the hash
    my @accs = sort { $self->{'_cache_number_hash'}->{$a} <=> $self->{'_cache_number_hash'}->{$b} } keys %{$self->{'_cache_number_hash'}};

    my $acc = shift @accs;
    # remove this guy
    my $seq = $self->{'_cache_acc_hash'}->{$acc};

    delete $self->{'_cache_number_hash'}->{$acc};
    delete $self->{'_cache_id_hash'}->{$seq->id};
    delete $self->{'_cache_acc_hash'}->{$acc};
  }

  # up the number, register this sequence into the hash.
  $self->{'_cache_id_hash'}->{$seq->id} = $seq->accession;
  $self->{'_cache_acc_hash'}->{$seq->accession} = $seq;
  $self->{'_cache_number_hash'}->{$seq->accession} = $self->{'_cache_number'}++;

  return $seq;

}

sub _number_free {

  my $self = shift;

  return $self->number - scalar(keys %{$self->{'_cache_number_hash'}});

}

sub get_Seq_by_version {

   my ($self,@args) = @_;
   $self->throw("Not implemented it");

}

General documentation

Ewan Birney

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://bio.perl.org/bioperl-bugs/

The rest of the documentation details each of the object
methods. Internal methods are usually preceded with a _