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Stored size: 1.99 KB
Contents
module ActiveFedora
module RdfList
attr_reader :graph, :subject
def initialize(graph, subject)
@graph = graph
@subject = subject
first = graph.query([subject, RDF.first, nil]).first
graph.insert([subject, RDF.first, RDF.nil]) unless first
graph.insert([subject, RDF.rest, RDF.nil])
end
def first
self[0]
end
def [](idx)
idx == 0 ? head.value : tail[idx-1]
end
def []=(idx, value)
idx == 0 ? head.value=value : tail_or_create(idx-1).value=value
end
def size
if tail
tail.size + 1
elsif graph.query([subject, RDF.first, RDF.nil]).first
0
else
1
end
end
def inspect
"[ #{value ? value.inspect : 'nil'}, #{tail.inspect}]"
end
def value
v = graph.query([subject, RDF.first, nil]).first
return v.object if v.object.uri?
if v.object.resource?
type = graph.query([v.object, RDF.type, nil]).first
return ActiveFedora::RdfNode.rdf_registry[type.object].new(graph, v.object)
end
v
end
def value=(obj)
graph.delete([subject, RDF.first, RDF.nil])
if obj.respond_to? :rdf_subject
graph.insert([subject, RDF.first, obj.rdf_subject]) # an ActiveFedora::RdfObject
else
graph.insert([subject, RDF.first, obj])
end
end
def head
@head ||= self.class.new(graph, subject)
end
def tail
rest = graph.query([subject, RDF.rest, nil]).first
return if rest.object == RDF.nil
self.class.new(graph, rest.object)
end
def tail_or_create(idx)
rest = graph.query([subject, RDF.rest, nil]).first
obj = if rest.object != RDF.nil
self.class.new(graph, rest.object)
else
#add a tail
graph.delete([subject, RDF.rest, RDF.nil])
tail = RDF::Node.new
graph.insert([subject, RDF.rest, tail])
self.class.new(graph, tail)
end
idx == 0 ? obj : obj.tail_or_create(idx-1)
end
end
end
Version data entries
18 entries across 18 versions & 1 rubygems