Class: RDF::HamsterRepo

Inherits:
Repository
  • Object
show all
Defined in:
lib/rdf/hamster_repo.rb

Overview

Sub-class of RDF::Repository with order-preserving properties.

Defined Under Namespace

Modules: VERSION

Constant Summary collapse

DEFAULT_GRAPH = 
false

Instance Method Summary collapse

Constructor Details

#initialize(uri: nil, title: nil, **options) {|repository| ... } ⇒ HamsterRepo

Initializes this repository instance.

Parameters:

  • uri (URI, #to_s) (defaults to: nil) —

    (nil)

  • title (String, #to_s) (defaults to: nil) —

    (nil)

  • options (Hash{Symbol => Object})

Options Hash (**options):

  • :with_graph_name (Boolean) — default: true —

    Indicates that the repository supports named graphs, otherwise, only the default graph is supported.

  • :with_validity (Boolean) — default: true —

    Indicates that the repository supports named validation.

  • :transaction_class (Boolean) — default: SerializedTransaction —

    Specifies the RDF::Transaction implementation to use in this Repository.

Yields:

  • (repository)

Yield Parameters:

  • repository (Repository) 


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# File 'lib/rdf/hamster_repo.rb', line 36

def initialize(uri: nil, title: nil, **options, &block)
  @data = options.delete(:data) || Hamster::Hash.new
  super do
    if block_given?
      case block.arity
        when 1 then block.call(self)
        else instance_eval(&block)
      end
    end
  end
end

Instance Method Details

#apply_changeset(changeset) ⇒ Object

See Also:

  • Mutable#apply_changeset


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# File 'lib/rdf/hamster_repo.rb', line 163

def apply_changeset(changeset)
  data = @data
  changeset.deletes.each do |del|
    if del.constant?
      data = delete_from(data, del)
    else
      # we need this condition to handle wildcard statements
      query_pattern(del) { |stmt| data = delete_from(data, stmt) }
    end
  end
  changeset.inserts.each { |ins| data = insert_to(data, ins) }
  @data = data
end

#graph? ⇒ Boolean #graph?(name) ⇒ Boolean Also known as: has_graph?

Overloads:

  • #graph? ⇒ Boolean

    Returns false to indicate that this is not a graph.

    Returns:

    • (Boolean)
  • #graph?(name) ⇒ Boolean

    Returns true if self contains the given RDF graph_name.

    Parameters:

    • graph_name (RDF::Resource, false) —

      Use value false to query for the default graph_name

    Returns:

    • (Boolean) 


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# File 'lib/rdf/hamster_repo.rb', line 97

def graph?(*args)
  case args.length
  when 0 then false
  when 1 then @data.key?(args.first)
  else raise ArgumentError("wrong number of arguments (given #{args.length}, expected 0 or 1)")
  end
end

#isolation_level ⇒ Object

See Also:

  • Dataset#isolation_level


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# File 'lib/rdf/hamster_repo.rb', line 179

def isolation_level
  :serializable
end

#snapshot ⇒ Dataset

A readable & queryable snapshot of the repository for isolated reads.

Returns:

  • (Dataset) —

    an immutable Dataset containing a current snapshot of the Repository contents.

See Also:

  • Mutable#snapshot


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# File 'lib/rdf/hamster_repo.rb', line 190

def snapshot
  self.class.new(data: @data).freeze
end

#statement? ⇒ Boolean #statement?(statement) ⇒ Object Also known as: has_statement?

Overloads:

  • #statement? ⇒ Boolean

    Returns false indicating this is not an RDF::Statemenet.

    Returns:

    • (Boolean)

    See Also:

    • Value#statement?
  • #statement?(statement) ⇒ Object

    See Also:

    • Enumerable#statement?


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# File 'lib/rdf/hamster_repo.rb', line 133

def statement?(*args)
  case args.length
  when 0 then false
  when 1 then args.first && statement_in?(@data, args.first)
  else raise ArgumentError("wrong number of arguments (given #{args.length}, expected 0 or 1)")
  end
end

#supports?(feature) ⇒ Boolean

Returns true if this respository supports the given feature.

This repository supports list_terms.

Returns:

  • (Boolean) 


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# File 'lib/rdf/hamster_repo.rb', line 52

def supports?(feature)
  case feature.to_sym
  when :atomic_write     then true
  when :rdfstar          then true
  when :snapshots        then true
  else super
  end
end

#to_query ⇒ RDF::Query

Creates a query from the statements in this repository, turning blank nodes into non-distinguished variables. This can be used to determine if this repository is logically a subset of another repository.

Returns:

  • (RDF::Query) 


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# File 'lib/rdf/hamster_repo.rb', line 65

def to_query
  RDF::Query.new do |query|
    each do |statement|
      query.pattern RDF::Query::Pattern.from(statement, ndvars: true)
    end
  end
end