Module: RDF::Reasoner::Schema

Defined in:
lib/rdf/reasoner/schema.rb

Overview

Rules for generating RDFS entailment triples

Extends ‘RDF::URI` with specific entailment capabilities

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.included(mod) ⇒ Object 



172
173
 
# File 'lib/rdf/reasoner/schema.rb', line 172

def self.included(mod)
end

Instance Method Details

#domain_compatible_schema?(resource, queryable, options = {}) ⇒ Boolean

Schema.org requires that if the property has a domain, and the resource has a type that some type matches some domain.

Note that this is different than standard entailment, which simply asserts that the resource has every type in the domain, but this is more useful to check if published data is consistent with the vocabulary definition.

If ‘resource` is of type `schema:Role`, `resource` is domain acceptable if any other resource references `resource` using this property.

Parameters:

  • resource (RDF::Resource)
  • queryable (RDF::Queryable)
  • options (Hash{Symbol => Object}) (defaults to: {})

Options Hash (options):

  • :types (Array<RDF::Vocabulary::Term>) —

    Fully entailed types of resource, if not provided, they are queried

Returns:

  • (Boolean)

Raises:



25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
 
# File 'lib/rdf/reasoner/schema.rb', line 25

def domain_compatible_schema?(resource, queryable, options = {})
  raise RDF::Reasoner::Error, "#{self} can't get domains" unless property?
  domains = Array(self.domainIncludes) - [RDF::OWL.Thing]

  # Fully entailed types of the resource
  types = entailed_types(resource, queryable, options) unless domains.empty?

  # Every domain must match some entailed type
  resource_acceptable = Array(types).empty? || domains.any? {|d| types.include?(d)}

  # Resource may still be acceptable if types include schema:Role, and any any other resource references `resource` using this property
  resource_acceptable ||
    types.include?(RDF::Vocab::SCHEMA.Role) &&
      !queryable.query(predicate: self, object: resource).empty?
end

#literal_range?(ranges) ⇒ Boolean

Are all ranges literal?

Parameters:

  • ranges (Array<RDF::UR>)

Returns:

  • (Boolean) 


158
159
160
161
162
163
164
165
166
167
168
169
170
 
# File 'lib/rdf/reasoner/schema.rb', line 158

def literal_range?(ranges)
  ranges.all? do |range|
    case range
    when RDF::RDFS.Literal, RDF::Vocab::SCHEMA.Text, RDF::Vocab::SCHEMA.Boolean, RDF::Vocab::SCHEMA.Date,
         RDF::Vocab::SCHEMA.DateTime, RDF::Vocab::SCHEMA.Time, RDF::Vocab::SCHEMA.URL,
         RDF::Vocab::SCHEMA.Number, RDF::Vocab::SCHEMA.Float, RDF::Vocab::SCHEMA.Integer
      true
    else
      # If this is an XSD range, look for appropriate literal
      range.start_with?(RDF::XSD.to_s)
    end
  end
end

#range_compatible_schema?(resource, queryable, options = {}) ⇒ Boolean

Schema.org requires that if the property has a range, and the resource has a type that some type matches some range. If the resource is a datatyped Literal, and the range includes a datatype, the resource must be consistent with that.

If ‘resource` is of type `schema:Role`, it is range acceptable if it has the same property with an acceptable value.

If ‘resource` is of type `rdf:List` (must be previously entailed), it is range acceptable if all members of the list are otherwise range acceptable on the same property.

Also, a plain literal (or schema:Text) is always compatible with an object range.

Parameters:

  • resource (RDF::Resource)
  • queryable (RDF::Queryable)
  • options (Hash{Symbol => Object}) (defaults to: {}) —

    ({})

Options Hash (options):

  • :types (Array<RDF::Vocabulary::Term>) —

    Fully entailed types of resource, if not provided, they are queried

Returns:

  • (Boolean)

Raises:



55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
 
# File 'lib/rdf/reasoner/schema.rb', line 55

def range_compatible_schema?(resource, queryable, options = {})
  raise RDF::Reasoner::Error, "#{self} can't get ranges" unless property?
  if !(ranges = Array(self.rangeIncludes) - [RDF::OWL.Thing]).empty?
    if resource.literal?
      ranges.any? do |range|
        case range
        when RDF::RDFS.Literal  then true
        when RDF::Vocab::SCHEMA.Text   then resource.plain? || resource.datatype == RDF::Vocab::SCHEMA.Text
        when RDF::Vocab::SCHEMA.Boolean
          [RDF::Vocab::SCHEMA.Boolean, RDF::XSD.boolean].include?(resource.datatype) ||
          resource.plain? && RDF::Literal::Boolean.new(resource.value).valid?
        when RDF::Vocab::SCHEMA.Date
          # Schema.org date based on ISO 8601, mapped to appropriate XSD types for validation
          case resource
          when RDF::Literal::Date, RDF::Literal::Time, RDF::Literal::DateTime, RDF::Literal::Duration
            resource.valid?
          else
            ISO_8601.match(resource.value)
          end
        when RDF::Vocab::SCHEMA.DateTime
          resource.datatype == RDF::Vocab::SCHEMA.DateTime ||
          resource.is_a?(RDF::Literal::DateTime) ||
          resource.plain? && RDF::Literal::DateTime.new(resource.value).valid?
        when RDF::Vocab::SCHEMA.Duration
          value = resource.value
          value = "P#{value}" unless value.start_with?("P")
          resource.datatype == RDF::Vocab::SCHEMA.Duration ||
          resource.is_a?(RDF::Literal::Duration) ||
          resource.plain? && RDF::Literal::Duration.new(value).valid?
        when RDF::Vocab::SCHEMA.Time
          resource.datatype == RDF::Vocab::SCHEMA.Time ||
          resource.is_a?(RDF::Literal::Time) ||
          resource.plain? && RDF::Literal::Time.new(resource.value).valid?
        when RDF::Vocab::SCHEMA.Number
          resource.is_a?(RDF::Literal::Numeric) ||
          [RDF::Vocab::SCHEMA.Number, RDF::Vocab::SCHEMA.Float, RDF::Vocab::SCHEMA.Integer].include?(resource.datatype) ||
          resource.plain? && RDF::Literal::Integer.new(resource.value).valid? ||
          resource.plain? && RDF::Literal::Double.new(resource.value).valid?
        when RDF::Vocab::SCHEMA.Float
          resource.is_a?(RDF::Literal::Double) ||
          [RDF::Vocab::SCHEMA.Number, RDF::Vocab::SCHEMA.Float].include?(resource.datatype) ||
          resource.plain? && RDF::Literal::Double.new(resource.value).valid?
        when RDF::Vocab::SCHEMA.Integer
          resource.is_a?(RDF::Literal::Integer) ||
          [RDF::Vocab::SCHEMA.Number, RDF::Vocab::SCHEMA.Integer].include?(resource.datatype) ||
          resource.plain? && RDF::Literal::Integer.new(resource.value).valid?
        when RDF::Vocab::SCHEMA.URL
          resource.datatype == RDF::Vocab::SCHEMA.URL ||
          resource.datatype == RDF::XSD.anyURI ||
          resource.plain? && RDF::Literal::AnyURI.new(resource.value).valid?
        else
          # If may be an XSD range, look for appropriate literal
          if range.start_with?(RDF::XSD.to_s)
            if resource.datatype == RDF::URI(range)
              true
            else
              # Valid if cast as datatype
              resource.plain? && RDF::Literal(resource.value, datatype: RDF::URI(range)).valid?
            end
          else
            # Otherwise, presume that the range refers to a typed resource. This is allowed if the value is a plain literal
            resource.plain?
          end
        end
      end
    elsif %w(True False).map {|v| RDF::Vocab::SCHEMA[v]}.include?(resource) && ranges.include?(RDF::Vocab::SCHEMA.Boolean)
      true # Special case for schema boolean resources
    elsif ranges.include?(RDF::Vocab::SCHEMA.URL) && resource.uri?
      true # schema:URL matches URI resources
    elsif ranges == [RDF::Vocab::SCHEMA.Text] && resource.uri?
      # Allowed if resource is untyped
      entailed_types(resource, queryable, options).empty?
    elsif literal_range?(ranges)
      false # If resource isn't literal, this is a range violation
    else
      # Fully entailed types of the resource
      types = entailed_types(resource, queryable, options)

      # Every range must match some entailed type
      resource_acceptable = Array(types).empty? || ranges.any? {|d| types.include?(d)}

      # Resource may still be acceptable if it has the same property with an acceptable value
      resource_acceptable ||

      # Resource also acceptable if it is a Role, and the Role object contains the same predicate having a compatible object
      types.include?(RDF::Vocab::SCHEMA.Role) &&
        queryable.query(subject: resource, predicate: self).any? do |stmt|
          acc = self.range_compatible_schema?(stmt.object, queryable)
          acc
        end ||
      # Resource also acceptable if it is a List, and every member of the list is range compatible with the predicate
      (list = RDF::List.new(subject: resource, graph: queryable)).valid? && list.all? do |member|
        self.range_compatible_schema?(member, queryable)
      end
    end
  else
    true
  end
end