Class: RDF::N3::Algebra::Time::InSeconds

Inherits:
ResourceOperator
  • Object
show all
Defined in:
lib/rdf/n3/algebra/time/in_seconds.rb

Overview

Iff the subject is a ‘xsd:dateTime` and the object is the integer number of seconds since the beginning of the era on a given system. Don’t assume a particular value, always test for it. The object can be calculated as a function of the subject.

See Also:

Constant Summary collapse

NAME = 
:timeInSeconds
URI = 
RDF::N3::Time.inSeconds

Instance Attribute Summary

Attributes included from Enumerable

#existentials, #universals

Instance Method Summary collapse

Methods inherited from ResourceOperator

#as_literal, #execute

Methods included from Builtin

#each, #evaluate, #hash, #rank, #to_uri

Instance Method Details

#input_operand ⇒ RDF::Term

Return both subject and object operands.

Returns:



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# File 'lib/rdf/n3/algebra/time/in_seconds.rb', line 54

def input_operand
  RDF::N3::List.new(values: operands)
end

#resolve(resource, position:) ⇒ RDF::Term

The time:inseconds operator takes may have either a bound subject or object.

Parameters:

  • resource (RDF::Term)
  • position (:subject, :object)

Returns:

See Also:

  • ResourceOperator#evaluate


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# File 'lib/rdf/n3/algebra/time/in_seconds.rb', line 17

def resolve(resource, position:)
  case position
  when :subject
    case resource
    when RDF::Query::Variable
      resource
    when RDF::Literal
      # Subject evaluates to seconds from the epoc
      RDF::Literal::Integer.new(resource.as_datetime.object.strftime("%s"))
    else
      nil
    end
  when :object
    case resource
    when RDF::Query::Variable
      resource
    when RDF::Literal
      resource = resource.as_number
      # Object evaluates to the DateTime representation of the seconds form the epoc
      RDF::Literal(RDF::Literal::DateTime.new(::Time.at(resource).utc.to_datetime).to_s)
    else
      nil
    end
  end
end

#valid?(subject, object) ⇒ Boolean

Either subject or object must be a bound resource

Returns:

  • (Boolean) 


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# File 'lib/rdf/n3/algebra/time/in_seconds.rb', line 44

def valid?(subject, object)
  return true if subject.literal? || object.literal?
  log_error(NAME) {"subject or object are not literals: #{subject.inspect}, #{object.inspect}"}
  false
end