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# Copyright (c) 1997-2018
# Ewgenij Gawrilow, Michael Joswig (Technische Universitaet Berlin, Germany)
# http://www.polymake.org
#
# This program is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by the
# Free Software Foundation; either version 2, or (at your option) any
# later version: http://www.gnu.org/licenses/gpl.txt.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#-------------------------------------------------------------------------------
#
# This file is part of the polymake database interface polyDB.
#
# @author Silke Horn, Andreas Paffenholz
# http://solros.de
# http://www.mathematik.tu-darmstadt.de/~paffenholz
#
package PolyDB::DBCursor;
# options:
# db
# collection
# query
# skip
# limit
# sort_by
# local
# username
# password
# host
# the two members used externally are cursor and size.
# The latter is necessery as the count method for cursors into MongoDB is deprecated. Hence we need to check the size of the collection instead
use Polymake::Struct (
[ new => '$$@' ],
[ '$query' => '#1' ],
[ '%options' => '#2' ],
'$database',
'$collection',
'$username',
'$password',
'$size',
'$cursor',
'$local',
);
sub new {
my $self = &_new;
$self->local = 0;
$self->username = $PolyDB::default::db_user;
$self->password = $PolyDB::default::db_pwd;
$self->database = defined($self->options->{db}) ? $self->options->{db} : $PolyDB::default::db_database_name;
$self->collection = defined($self->options->{collection}) ? $self->options->{collection} : $PolyDB::default::db_database_name;
my $client = Client::get_client($self->local, $self->username, $self->password);
if ( !defined($self->options->{sort_by}) ) {
$self->options->{sort_by} = {"_id" => 1};
}
if ( !defined($self->options->{skip}) ) {
$self->options->{skip} = 0;
}
dbg_print("connection established as user ".$self->username."\n") if ($DebugLevel > 0);
dbg_print("using database ".$self->database." and collection ".$self->collection."\n") if ($DebugLevel > 0);
my $collection = $client->get_database($self->database)->get_collection($self->collection);
$self->size = $collection->count($self->query, {limit=>$self->options->{limit}, skip => $self->options->{skip}});
$self->cursor = $collection->find($self->query)->sort($self->options->{sort_by})->limit($self->options->{limit})->skip($self->options->{skip});
$self->cursor->immortal(1);
$self->cursor->has_next; # this seems to be necessary to circumvent restricted hash problems...
$self;
}
sub next {
my ($self) = @_;
my $p = $self->cursor->next;
unless ($p) {
warn_print("no further object in query");
return;
}
return PolymakeJsonConversion::perl2polymake($p, $self->database, $self->collection)
}
sub has_next {
my ($self) = @_;
return $self->cursor->has_next;
}
sub at_end {
my ($self) = @_;
return !$self->cursor->has_next;
}
# The number of objects matching [[QUERY]] repecting the limit.
# @return Int
sub count {
my ($self) = @_;
return $self->size;
};
1
# Local Variables:
# mode: perl
# cperl-indent-level:3
# indent-tabs-mode:nil
# End:
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