module RDF::Mutable

Classes that include this module must implement the methods ‘#insert_statement`, `#delete_statement` and `#each_statement`.

@see RDF::Graph @see RDF::Repository

Public Instance Methods

<<(data) click to toggle source

Inserts RDF data into ‘self`.

@param [RDF::Enumerable, RDF::Statement, to_rdf] data @raise [TypeError] if ‘self` is immutable @return [Mutable] @see RDF::Writable#<<

Calls superclass method RDF::Writable#<<
# File lib/rdf/mixin/mutable.rb, line 69
def <<(data)
  raise TypeError.new("#{self} is immutable") if immutable?

  super # RDF::Writable#<<
end
apply_changeset(changeset) click to toggle source

Applies the given changeset

If ‘#supports?(:atomic_write)` is `true`, this must apply the changeset atomically. Otherwise, it should offer an efficient implementation of a combined delete/insert of the changeset.

@param changeset [RDF::Changeset] the changeset to apply @return [Boolean] true if the changeset has been applied

# File lib/rdf/mixin/mutable.rb, line 200
def apply_changeset(changeset)
  delete_insert(changeset.deletes, changeset.inserts)
end
clear() click to toggle source

Deletes all RDF statements from ‘self`.

@raise [TypeError] if ‘self` is immutable @return [Mutable]

# File lib/rdf/mixin/mutable.rb, line 222
def clear
  raise TypeError.new("#{self} is immutable") if immutable?

  if respond_to?(:clear_statements, true)
    clear_statements
  else
    delete_statements(self)
  end

  return self
end
Also aliased as: clear!
clear!()
Alias for: clear
delete(*statements) click to toggle source

Deletes RDF statements from ‘self`. If any statement contains a {Query::Variable}, it is considered to be a pattern, and used to query self to find matching statements to delete.

@note using splat argument syntax with excessive arguments provided significantly affects performance. Use Enumerator form for large numbers of statements.

@overload delete(*statements)

@param  [Array<RDF::Statement>] statements
@raise  [TypeError] if `self` is immutable
@return [self]

@overload delete(statements)

@param  [Enumerable<RDF::Statement>] statements
@raise  [TypeError] if `self` is immutable
@return [self]
# File lib/rdf/mixin/mutable.rb, line 155
def delete(*statements)
  raise TypeError.new("#{self} is immutable") if immutable?

  coerce_statements(statements, query: true, constant: true) do |value|
    delete_statements(value)
  end

  return self
end
Also aliased as: delete!
delete!(*statements)
Alias for: delete
delete_insert(deletes, inserts) click to toggle source

Performs a set of deletes and inserts as a combined operation.

@note in the base implementation, this is equivalent to calling ‘#delete`

and `#insert` sequentially. This method is preferred to take advantage 
of (e.g.) `RDF::Repositories` that can execute the operation in a single
request.

@param [Enumerable<RDF::Statement>, Array<RDF::Statement>] deletes @param [Enumerable<RDF::Statement>, Array<RDF::Statement>] inserts @raise [TypeError] if ‘self` is immutable @return [Mutable] self

@see delete @see insert

# File lib/rdf/mixin/mutable.rb, line 182
def delete_insert(deletes, inserts)
  deletes.respond_to?(:each_statement) ? delete(deletes) : delete(*deletes)
  inserts.respond_to?(:each_statement) ? insert(inserts) : insert(*inserts)

  self
end
Also aliased as: delete_insert!
delete_insert!(deletes, inserts)
Alias for: delete_insert
immutable?() click to toggle source

Returns ‘true` if `self` is immutable.

@return [Boolean] @see mutable?

# File lib/rdf/mixin/mutable.rb, line 28
def immutable?
  !mutable?
end
insert(*statements) click to toggle source

Inserts RDF statements into ‘self`.

@note using splat argument syntax with excessive arguments provided significantly affects performance. Use Enumerator form for large numbers of statements.

@overload insert(*statements)

@param  [Array<RDF::Statement>] statements
@raise  [TypeError] if `self` is immutable
@return [self]

@overload insert(statements)

@param  [Enumerable<RDF::Statement>] statements
@raise  [TypeError] if `self` is immutable
@return [self]

@see RDF::Writable#insert

Calls superclass method RDF::Writable#insert
# File lib/rdf/mixin/mutable.rb, line 93
def insert(*statements)
  raise TypeError.new("#{self} is immutable") if immutable?

  super # RDF::Writable#insert
end
load(url, graph_name: nil, **options) click to toggle source

Loads RDF statements from the given file or URL into ‘self`.

@param [String, to_s] url @param [Hash{Symbol => Object}] options

Options from {RDF::Reader.open}

@option options [RDF::Resource] :graph_name

Set set graph name of each loaded statement

@return [void]

# File lib/rdf/mixin/mutable.rb, line 41
def load(url, graph_name: nil, **options)
  raise TypeError.new("#{self} is immutable") if immutable?

  Reader.open(url, base_uri: url, **options) do |reader|
    if graph_name
      statements = []
      reader.each_statement do |statement|
        statement.graph_name = graph_name
        statements << statement
      end
      insert_statements(statements)
      statements.size
    else
      insert_statements(reader)
      nil
    end
  end
end
Also aliased as: load!
load!(url, graph_name: nil, **options)
Alias for: load
method_missing(meth, *args) click to toggle source

@overload from_reader

Implements #from_reader for each available instance of {RDF::Reader},
based on the reader symbol.

Arguments are passed to Reader.new.

@return [String]
@see {RDF::Reader.sym}
Calls superclass method
# File lib/rdf/mixin/mutable.rb, line 245
def method_missing(meth, *args)
  reader = RDF::Reader.for(meth.to_s[5..-1].to_sym) if meth.to_s[0,5] == "from_"
  if reader
    self << reader.new(*args)
  else
    super
  end
end
mutable?() click to toggle source

Returns ‘true` if `self` is mutable.

@return [Boolean] @see immutable?

# File lib/rdf/mixin/mutable.rb, line 19
def mutable?
  writable?
end
respond_to_missing?(name, include_private = false) click to toggle source

@note this instantiates an entire reader; it could probably be done more

efficiently by refactoring `RDF::Reader` and/or `RDF::Format` to expose
a list of valid format symbols.
Calls superclass method
# File lib/rdf/mixin/mutable.rb, line 258
def respond_to_missing?(name, include_private = false)
  return RDF::Reader.for(name.to_s[5..-1].to_sym) if name.to_s[0,5] == 'from_'
  super 
end
snapshot() click to toggle source

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

This method must be implemented when ‘#supports(:snapshots)` is `true`.

@return [Dataset] an immutable Dataset containing a current snapshot of

the Repository contents.

@raise [NotImplementederror] when snapshots aren’t implemented for the

class
# File lib/rdf/mixin/mutable.rb, line 213
def snapshot
  raise NotImplementedError, "#{self.class} does not implement snapshots"
end
update(*statements) click to toggle source

Updates RDF statements in ‘self`.

‘#update([subject, predicate, object])` is equivalent to `#delete([subject, predicate, nil])` followed by `#insert([subject, predicate, object])` unless `object` is `nil`.

@note using splat argument syntax with excessive arguments provided significantly affects performance. Use Enumerator form for large numbers of statements.

@overload update(*statements)

@param  [Array<RDF::Statement>] statements
@raise  [TypeError] if `self` is immutable
@return [self]

@overload update(statements)

@param  [Enumerable<RDF::Statement>] statements
@raise  [TypeError] if `self` is immutable
@return [self]
# File lib/rdf/mixin/mutable.rb, line 119
def update(*statements)
  raise TypeError.new("#{self} is immutable") if immutable?
  statements = statements[0] if statements.length == 1 && statements[0].is_a?(Enumerable)

  statements.each do |statement|
    if (statement = Statement.from(statement))
      if statement.object?
        delete_insert([[statement.subject, statement.predicate, nil]], [statement])
      else
        delete([statement.subject, statement.predicate, nil])
      end
    end
  end
end
Also aliased as: update!
update!(*statements)
Alias for: update

Protected Instance Methods

delete_statement(statement) click to toggle source

Deletes an RDF statement from the underlying storage.

Subclasses of {RDF::Repository} must implement this method, except if they are immutable.

@param [RDF::Statement] statement @return [void] @abstract

# File lib/rdf/mixin/mutable.rb, line 292
def delete_statement(statement)
  raise NotImplementedError.new("#{self.class}#delete_statement")
end
delete_statements(statements) click to toggle source

Deletes the given RDF statements from the underlying storage.

Defaults to invoking {RDF::Mutable#delete_statement} for each given statement.

Subclasses of {RDF::Repository} may wish to override this method if they are capable of more efficiently deleting multiple statements at once.

@param [RDF::Enumerable] statements @return [void]

# File lib/rdf/mixin/mutable.rb, line 276
def delete_statements(statements)
  each = statements.respond_to?(:each_statement) ? :each_statement : :each
  statements.__send__(each) do |statement|
    delete_statement(statement)
  end
end