Class: EasySparql::Resource

Inherits:
Object
  • Object
show all
Defined in:
lib/easy_sparql/resource.rb

Constant Summary collapse

@@namespaces = 
{
  'ws' => 'http://wsarchive.prototype0.net/ontology/',
  'po' => 'http://purl.org/ontology/po/',
  'dc' => 'http://purl.org/dc/elements/1.1/',
  'rdf' => 'http://www.w3.org/1999/02/22-rdf-syntax-ns#',
  'rdfs' => 'http://www.w3.org/2000/01/rdf-schema#',
}
@@property_map = 
{}
@@cache = 
nil

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(uri = nil, bindings = []) ⇒ Resource

Returns a new instance of Resource.



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# File 'lib/easy_sparql/resource.rb', line 62

def initialize(uri = nil, bindings = [])
  @properties = []
  @method_bindings = {}
  @uri = uri
  bindings.each do |property, value|
    value = value.object if value.respond_to? :object
    namespaces_i = @@namespaces.invert
    namespaces_i.each do |base, short|
      if property.to_s.start_with?(base)
        method_name = property.to_s.sub(base, short + '_')
        # If we already have a binding for that method, this
        # method now outputs an array and we pluralise the method name
        # The singular method name gives the first element of the array
        if @method_bindings.has_key? method_name.pluralize.to_sym
            @method_bindings[method_name.pluralize.to_sym] << value
        elsif @method_bindings.has_key? method_name.to_sym
          old_value = @method_bindings[method_name.to_sym]
          @method_bindings[method_name.pluralize.to_sym] = [ old_value, value ]
        else
          @method_bindings[method_name.to_sym] = value
        end
        @properties << method_name.to_sym
      end
    end
  end
  @properties.uniq!
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(name, *args, &block) ⇒ Object (protected) 



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# File 'lib/easy_sparql/resource.rb', line 120

def method_missing(name, *args, &block)
  if args.empty? && @method_bindings.has_key?(name.to_sym)
    value = @method_bindings[name.to_sym]
    if value.class == RDF::URI
      # Following our nose and caching the result in the object
      if @@property_map.has_key? name.to_sym
        @method_bindings[name.to_sym] = @@property_map[name.to_sym].find_by_uri(value)
      else
        @method_bindings[name.to_sym] = Resource.find_by_uri(value)
      end
    else
      value
    end
  else
    nil
  end
end

Instance Attribute Details

#method_bindings ⇒ Object (readonly)

Returns the value of attribute method_bindings.



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# File 'lib/easy_sparql/resource.rb', line 34

def method_bindings
  @method_bindings
end

#namespaces ⇒ Object (readonly)

Returns the value of attribute namespaces.



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# File 'lib/easy_sparql/resource.rb', line 36

def namespaces
  @namespaces
end

#properties ⇒ Object (readonly)

Returns the value of attribute properties.



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# File 'lib/easy_sparql/resource.rb', line 35

def properties
  @properties
end

#uri ⇒ Object

Returns the value of attribute uri.



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# File 'lib/easy_sparql/resource.rb', line 33

def uri
  @uri
end

Class Method Details

.add_namespace(mappings) ⇒ Object 



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# File 'lib/easy_sparql/resource.rb', line 52

def self.add_namespace(mappings)
  mappings.each do |k, v|
    @@namespaces[k] = v
  end
end

.cache ⇒ Object 



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# File 'lib/easy_sparql/resource.rb', line 44

def self.cache
  @@cache
end

.cache=(cache) ⇒ Object 



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# File 'lib/easy_sparql/resource.rb', line 40

def self.cache=(cache)
  @@cache = cache
end

.find_by_uri(uri) ⇒ Object 



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# File 'lib/easy_sparql/resource.rb', line 90

def self.find_by_uri(uri)
  cached_resource = @@cache.get(uri) if @@cache
  return cached_resource if cached_resource
  resource = find_by_uri_from_sparql(uri)
  @@cache.set(uri, resource) if @@cache
  resource
end

.find_by_uri_from_sparql(uri) ⇒ Object 



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# File 'lib/easy_sparql/resource.rb', line 98

def self.find_by_uri_from_sparql(uri)
  uri = RDF::URI.new(uri) if uri.class == String
  results = sparql.select.where([uri, :p, :o]).execute
  bindings = []
  results.each do |result|
    bindings << [ result.p, result.o ]
  end
  resource = new(uri, bindings)
end

.find_type(uri) ⇒ Object 



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# File 'lib/easy_sparql/resource.rb', line 108

def self.find_type(uri)
  uri = RDF::URI.new(uri) if uri.class == String
  results = sparql.select.where([uri, RDF.type, :type]).execute
  results[0][:type] unless results.empty?
end

.map(mapping) ⇒ Object 



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# File 'lib/easy_sparql/resource.rb', line 48

def self.map(mapping)
  @@property_map.merge! mapping
end

.namespaces ⇒ Object 



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# File 'lib/easy_sparql/resource.rb', line 58

def self.namespaces
  @@namespaces
end

.sparql ⇒ Object 



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# File 'lib/easy_sparql/resource.rb', line 114

def self.sparql
  EasySparql.store.sparql_client
end