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Contents
module SPARQL; module Algebra
class Operator
##
# The SPARQL GraphPattern `union` operator.
#
# @example
# (prefix ((: <http://example/>))
# (union
# (bgp (triple ?s ?p ?o))
# (graph ?g
# (bgp (triple ?s ?p ?o)))))
#
# @see http://www.w3.org/TR/rdf-sparql-query/#sparqlAlgebra
class Union < Operator::Binary
include Query
NAME = [:union]
##
# Executes each operand with `queryable` and performs the `union` operation
# by creating a new solution set consiting of all solutions from both operands.
#
# @param [RDF::Queryable] queryable
# the graph or repository to query
# @param [Hash{Symbol => Object}] options
# any additional keyword options
# @return [RDF::Query::Solutions]
# the resulting solution sequence
# @see http://www.w3.org/TR/rdf-sparql-query/#sparqlAlgebra
def execute(queryable, options = {})
debug(options) {"Union"}
solutions1 = operand(0).execute(queryable, options.merge(:depth => options[:depth].to_i + 1))
debug(options) {"=>(left) #{solutions1.inspect}"}
solutions2 = operand(1).execute(queryable, options.merge(:depth => options[:depth].to_i + 1))
debug(options) {"=>(right) #{solutions2.inspect}"}
@solutions = RDF::Query::Solutions.new(solutions1 + solutions2)
debug(options) {"=> #{@solutions.inspect}"}
@solutions
end
##
# Returns an optimized version of this query.
#
# If optimize operands, and if the first two operands are both Queries, replace
# with the unique sum of the query elements
#
# @return [Union, RDF::Query] `self`
def optimize
ops = operands.map {|o| o.optimize }.select {|o| o.respond_to?(:empty?) && !o.empty?}
@operands = ops
self
end
end # Union
end # Operator
end; end # SPARQL::Algebra
Version data entries
9 entries across 9 versions & 1 rubygems