NAME
    RDF::Trine::Store::File - Using a file with N-Triples as triplestore

VERSION
    Version 0.1

SYNOPSIS
    To be used as a normal triple store.

      my $store = RDF::Trine::Store::File->new($filename);
      $store->add_statement(RDF::Trine::Statement->new(
                                                       RDF::Trine::Node::Resource->new('http://example.org/a'),
                                                       RDF::Trine::Node::Resource->new('http://example.org/b'),
                                                       RDF::Trine::Node::Resource->new('http://example.org/c')
                                                      ));
      ...

METHODS
  new($filename)
    A constructor, takes a filename as parameter. If the file doesn't exist,
    it will be created.

  new_with_string('File;'.$filename)
    A constructor, takes a string config as parameter. If the file doesn't
    exist, it will be created. The string will typically begin with "File;",
    e.g.

      my $store = RDF::Trine::Store::File->new_with_string('File;/path/to/file.nt');

  new_with_config({ storetype => 'File', file => $filename});
    A constructor, takes a hashref config as parameter. If the file doesn't
    exist, it will be created. It needs to have a "storetype" key with
    "File" as the value, e.g.

      my $store = RDF::Trine::Store::File->new_with_config({ storetype => 'File', file => $filename});

  temporary_store
    Constructor that creates a temporary file to work on.

  add_statement($statement)
    Adds the specified $statement to the underlying model.

  get_statements($subject, $predicate, $object)
    Returns a stream object of all statements matching the specified
    subject, predicate and objects. Any of the arguments may be undef to
    match any value.

  count_statements($subject, $predicate, $object)
    Returns a count of all the statements matching the specified subject,
    predicate and objects. Any of the arguments may be undef to match any
    value.

  remove_statement($statement)
    Removes the specified $statement from the underlying model.

  remove_statements($subject, $predicate, $object)
    Removes all statement matching the specified subject, predicate and
    objects. Any of the arguments may be undef to match any value.

  get_contexts
    Contexts are not supported for this store.

  size
    Returns the number of statements in the store. Breaks if there are
    comments or empty lines in the file.

  etag
    Returns an etag based on the last modification time of the file. Note:
    This has resolution of one second, so it cannot be relied on for data
    that changes fast.

  nuke
    Permanently removes the store file and its data.

DISCUSSION
    This module is intended mostly as a simple backend to dump data to a
    file and do as little as possible in memory. Thus, it is mostly suitable
    in cases where a lot of data is written to file. It should be possible
    to use it as a SPARQL store with RDF::Query, but the performance is
    likely to be somewhere between terrible and abyssmal, so don't do that
    unless you are prepared to be waiting around.

    On the good side, adding statements should be pretty fast, as it just
    appends to a file. The "size" method should be pretty fast too, as it
    just counts the lines in that file. Finally, it supports the "etag"
    method, not perfectly, but that's still pretty good!

    It uses a lot of heuristics tied to the format chosen, i.e. N-Triples.
    That's a line-based format, with predictable amounts of whitespace,
    allowing us to create relatively simple regular expressions as search
    patterns in the file. This is likely to be somewhat fragile (it is
    making assumptions about the file that is true in the
    RDF::Trine::Serializer::Ntriples case, but not in the format), but it
    kinda works.

    It is important to note that this module does nothing to prevent you
    from adding duplicate statements like other stores should do. This is
    because it would dramatically reduce "add_statement" performance and
    thus kill the main use case for this module. Perhaps it could be made
    optional at some point, but for now, just be aware that this may not
    always return the right counts if two identical statements are inserted
    and possibly produce unexpected results if you against the advice above
    should attempt to use this a store for SPARQL.

    I've decided to use File::Data to actually do the work with the file.
    Locking and that kind of stuff is done there and is thus Not My Problem.
    If it is yours, then File::Data is probably the right place to go and
    fix it.

TODO
    This is beta-quality software but it has a pretty comprehensive test
    suite. These are some things that could be done:

    *   Support bulk operations (somewhat less important)

    *   Find a way to do duplicate checking efficiently

AUTHOR
    Kjetil Kjernsmo, "<kjetilk at cpan.org>"

BUGS
    Please report any bugs or feature requests to "bug-rdf-trine-store-file
    at rt.cpan.org", or through the web interface at
    <http://rt.cpan.org/NoAuth/ReportBug.html?Queue=RDF-Trine-Store-File>. I
    will be notified, and then you'll automatically be notified of progress
    on your bug as I make changes.

SUPPORT
    You can find documentation for this module with the perldoc command.

        perldoc RDF::Trine::Store::File

    The perlrdf mailing list is the right place to seek help and discuss
    this module:

    <http://lists.perlrdf.org/listinfo/dev>

    You can also look for information at:

    *   RT: CPAN's request tracker (report bugs here)

        <http://rt.cpan.org/NoAuth/Bugs.html?Dist=RDF-Trine-Store-File>

    *   AnnoCPAN: Annotated CPAN documentation

        <http://annocpan.org/dist/RDF-Trine-Store-File>

    *   CPAN Ratings

        <http://cpanratings.perl.org/d/RDF-Trine-Store-File>

    *   Search CPAN

        <http://search.cpan.org/dist/RDF-Trine-Store-File/>

LICENSE AND COPYRIGHT
    Copyright 2011 Kjetil Kjernsmo.

    This program is free software; you can redistribute it and/or modify it
    under the terms of either: the GNU General Public License as published
    by the Free Software Foundation; or the Artistic License.

    See http://dev.perl.org/licenses/ for more information.

