Release 2.0.0

Ruby RDF 2.0

This is the 2.0 release of RDF.rb and related gems. This announces the general availability of RDF.rb 2.0.0 along with other gems collected in the linkeddata meta-gem. Note that this release introduces breaking changes from the 1.* version; in most cases, these are highlighted using deprecation messages if using 1.99.

New Features

• Readers and Writers now using RDF::Util::Logger for managing error, warning, information, and debug messages, which allow them to be managed more flexibly and consistently.

• Substantially revised RDF::Transaction, which now serves as a scope for ACID transactions. Transactions are now read-only by default; for read/write transactions, use Transaction.new(mutable: true) or Repository#transaction(mutable: true). Transactions can be applied to an RDF::Transactable (in the core: Repository or Graph).

• Introduced RDF::Changeset as a set of deletes & inserts which can be applied to a Mutable. The default RDF::Transaction for custom Repository implementations uses aChangeset, which is applied to the Repository.

• Introduced RDF::Dataset as a read-only super-class of Repository, which can be provided by using Repository#snapshot, among other methods.

• The in-memory Repository implementation now uses Hamster::Hash to implement a fully functional interface for updating repositories, saving a number of explicit dup operations in queries and allowing fully isolated snapshots and serializable transactions at minimal cost. As a side-effect, there is no guarantee that insert order of statements in a Graph or Repository will be maintained.

• The rdf command line executable is now pluggable, and can be extended by other gems implementing RDF::Format, RDF::Reader or RDF::Writer. Readers and Writers can define format-specific options, and individual commands can define their own options as well. Commands now have their own help messages.

• List#initialize now uses keyword arguments instead of positional arguments.

• Graph#initialize now uses keyword arguments instead of positional arguments.

• A new class RDF::Changeset has been added. This is meant to replace any
  previous use of RDF::Transaction, which in fact used to in RDF.rb 1.x
  represent more of a buffered changeset than a genuine transaction scope.

  • Instead of RDF::Transaction.execute, use RDF::Changeset.apply.
  • Instead of RDF::Transaction#execute, use RDF::Changeset#apply.

• The RDF::Transaction class has been substantially revamped, including
  some minor backwards-incompatible changes. These changes will mostly
  affect repository implementors, not so much general RDF.rb users.

  The changes reflect the expanded purpose of the class: instead of being a
  mere buffered changeset (for which, see RDF::Changeset), transactions
  are now intended to provide a proper ACID scope for repository queries and
  mutations.

  We always now also carefully distinguish between read-only and read/write
  transactions, in order to enable repository implementations to take out the
  appropriate locks for concurrency control. Note as well that transactions
  are now read-only by default; mutability must be explicitly requested on
  construction in order to obtain a read/write transaction.

  In case repository implementations should be unable to provide actual ACID
  guarantees for transactions, that must be clearly indicated in their
  documentation. Similarly, implementations should throw an exception when
  appropriate in case they don't provide write transaction support.

  • RDF::Transaction#initialize now takes the target repository as its
    first argument. Transactions are now always tied to a specific
    repository instance, instead of being free-floating objects as they used
    to be (for that, see RDF::Changeset).

  • RDF::Transaction now mixes in RDF::Queryable and RDF::Enumerable,
    enabling quad-pattern matches and BGP queries to execute in a proper
    transaction scope.

  • The RDF::Transaction#context accessor, and its aliases, have been
    removed. Transactions aren't necessarily scoped to a single graph only.

  • There is a new RDF::Transaction#repository accessor for retrieving the
    target repository object that the transaction operates upon.

  • There is a new RDF::Transaction#buffered? predicate for testing
    whether the changeset that constitutes a transaction is available for
    introspection. Particular repository implementations may support both
    options and permit the user the choice on transaction construction.

  • The RDF::Transaction#inserts and #deletes methods are deprecated.
    Instead, there is a new RDF::Transaction#changes accessor to retrieve
    an RDF::Changeset instance, which contains corresponding methods.
    For unbuffered transactions, #changes returns nil.

• Enumerables vs. Enumerators

  • RDF::Queryable#query and RDF::Query#execute did not return an enumerable, which may be an enumerator. Most internal uses return an Array now, which aides performance for small result sets, but potentially causes problems for large result sets. Implementations may still return an Enumerator, and Enumerators may be passed as arguments.
  • RDF::Enumerable#statements, #quads, #triples, #subjects, #predicates, #objects, and #contexts now return an array rather than an Enumerator.

Removed Interfaces from 1.*

These changes result in a DEPRECATION warning in 1.99, and errors in 2.*:

• Minimum Ruby version no MRI 2.0 or equivalent 2.3 or greater preferred.
• Numerous vocabularies have been moved to the rdf-vocab gem, for example RDF::Vocab::FOAF instead of RDF::FOAF.
• Many interfaces would take a :context option, this has been replaced with :graph_name to more properly correspond to RDF 1.1 concepts. This also includes #context and #context=, #has_context?, and #each_context methods in various modules and classes.
• Vocabulary.label_for is replaced with Vocabulary::Term#label* Vocabulary.comment_for is replaced with Vocabulary::Term#comment
• #write_graph and #write_statements are replaced with RDF::Writable#insert
• Writer#format_value is deprecated in favor of Writer#format_term
• NTriples::Reader no longer supports Surrogate Pairs.
• Many interfaces now use [keyword arguments][https://robots.thoughtbot.com/ruby-2-keyword-arguments] instead of positional arguments.
• List#initialize no longer uses positional arguments. This is a breaking change which cannot support backwards compatibility, but shouldn't affect most normal use.
• Graph#initialize no longer uses positional arguments.
• Transaction is completely changed, and existing use from 1.x is unlikely to work without modification in 2.x. Users of the 1.x Transaction who are not interested in ACID transactions should look at RDF::Changeset, which is more similar to the old interface.
• Vocabulary.load is deprecated, use Vocabulary.from_graph.

The following vocabularies are deprecated and have been moved to the rdf-vocab gem.

• RDF::CC - Creative Commons (CC)
• RDF::CERT - W3 Authentication Certificate (CERT)
• RDF::DC - Dublin Core (DC)
• RDF::DC11 - Dublin Core 1.1 (DC11) deprecated
• RDF::DOAP - Description of a Project (DOAP)
• RDF::EXIF - Exchangeable Image File Format (EXIF)
• RDF::FOAF - Friend of a Friend (FOAF)
• RDF::GEO - WGS84 Geo Positioning (GEO)
• RDF::GR - GoodRelations (GR)
• RDF::HT - Hypertext Transfer Protocol (HT)
• RDF::ICAL - RDF Calendar Workspace (ICAL)
• RDF::MA - Media Resources (MA)
• RDF::MO - Music Ontology (MO)
• RDF::OG - Open Graph protocol (OG)
• RDF::PROV - Provenance on the web (PROV)
• RDF::RSA - W3 RSA Keys (RSA)
• RDF::RSS - RDF Site Summary (RSS)
• RDF::SCHEMA - Schema.org (SCHEMA)
• RDF::SIOC - Semantically-Interlinked Online Communities (SIOC)
• RDF::SKOS - Simple Knowledge Organization System (SKOS)
• RDF::SKOSXL - SKOS eXtension for Labels (SKOSXL)
• RDF::V - RDF data vocabulary (V)
• RDF::VCARD - Ontology for vCards (VCARD)
• RDF::VMD - Data-Vocabulary.org (VMD)
• RDF::VOID - Vocabulary of Interlinked Datasets (VOID)
• RDF::VS - SemWeb Vocab Status ontology (VS)
• RDF::WDRS - Protocol for Web Description Resources (WDRS)
• RDF::WOT - Web of Trust (WOT)
• RDF::XHTML - Extensible HyperText Markup Language (XHTML)
• RDF::XHV - XHTML Vocabulary (XHV)

Ruby gems will not automatically load beta gems via gem update. To get these gems you must explicitly include them using gem install --pre linkeddata.