Class: GRel::QL::QueryContext

Inherits:
Object
  • Object
show all
Defined in:
lib/grel/ql.rb

Overview

end of to_triples

Constant Summary collapse

TUPLE = 
"TUPLE"
NODE = 
"NODE"

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(graph = nil) ⇒ QueryContext

Returns a new instance of QueryContext.



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# File 'lib/grel/ql.rb', line 286

def initialize(graph=nil)
  @id_counter = -1
  @filters_counter = -1
  @triples = []
  @optional_triples = []
  @optional_bgps = []
  @projection = {}
  @nodes = {}
  @graph = graph
  @optional = false
  @last_registered_subject = []
  @unions = []
  @limit = nil
  @offset = nil
  @orig_query = nil
  @query_keys = []
  @top_level = true
end

Instance Attribute Details

#last_registered_subject ⇒ Object (readonly)

Returns the value of attribute last_registered_subject.



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# File 'lib/grel/ql.rb', line 283

def last_registered_subject
  @last_registered_subject
end

#limit ⇒ Object

Returns the value of attribute limit.



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# File 'lib/grel/ql.rb', line 283

def limit
  @limit
end

#nodes ⇒ Object (readonly)

Returns the value of attribute nodes.



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# File 'lib/grel/ql.rb', line 283

def nodes
  @nodes
end

#offset ⇒ Object

Returns the value of attribute offset.



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# File 'lib/grel/ql.rb', line 283

def offset
  @offset
end

#optional ⇒ Object

Returns the value of attribute optional.



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# File 'lib/grel/ql.rb', line 284

def optional
  @optional
end

#optional_triples ⇒ Object

Returns the value of attribute optional_triples.



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# File 'lib/grel/ql.rb', line 284

def optional_triples
  @optional_triples
end

#order ⇒ Object (readonly)

Returns the value of attribute order.



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# File 'lib/grel/ql.rb', line 283

def order
  @order
end

#orig_query ⇒ Object (readonly)

Returns the value of attribute orig_query.



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# File 'lib/grel/ql.rb', line 283

def orig_query
  @orig_query
end

#projection ⇒ Object (readonly)

Returns the value of attribute projection.



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# File 'lib/grel/ql.rb', line 283

def projection
  @projection
end

#top_level ⇒ Object

Returns the value of attribute top_level.



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# File 'lib/grel/ql.rb', line 284

def top_level
  @top_level
end

#triples ⇒ Object

Returns the value of attribute triples.



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# File 'lib/grel/ql.rb', line 284

def triples
  @triples
end

#unions ⇒ Object

Returns the value of attribute unions.



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# File 'lib/grel/ql.rb', line 284

def unions
  @unions
end

Instance Method Details

#append(triples) ⇒ Object 



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# File 'lib/grel/ql.rb', line 331

def append(triples)
  if(@optional)
    @optional_triples += triples
  else
    @triples += triples
  end
end

#fresh_filter_predicate ⇒ Object 



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# File 'lib/grel/ql.rb', line 374

def fresh_filter_predicate
  @filters_counter+=1
  "?P_#{@id_counter}_#{@filters_counter}"
end

#next_node_id ⇒ Object 



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# File 'lib/grel/ql.rb', line 339

def next_node_id
  @id_counter += 1
  @id_counter
end

#node_to_optional(node_id) ⇒ Object

, last_registered_subject)



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# File 'lib/grel/ql.rb', line 368

def node_to_optional(node_id) #, last_registered_subject)
  @projection.delete(node_id)
  @nodes.delete(node_id)
  # @last_registered_subject << last_registered_subject
end

#query_keys ⇒ Object 



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# File 'lib/grel/ql.rb', line 313

def query_keys
  sets = [[@query_keys,@orig_query]]
  unions.each do |c|
    sets += c.query_keys
  end
  sets
end

#register_node(id, node_id, inverse = false) ⇒ Object 



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# File 'lib/grel/ql.rb', line 344

def register_node(id,node_id,inverse=false)
  @filters_counter = -1
  subject = id
  predicate = "?P_mg_#{node_id}"
  object = "?O_mg_#{node_id}" 
  if(id.nil?)
    subject = "?S_mg_#{node_id}"
    @projection[subject] = true if(!inverse)
  else
    @projection[id] = true if(!inverse)
  end

  @last_registered_subject << subject
  # @projection[predicate] = true
  # @projection[object] = true
  @nodes[node_id] = subject

  [subject, predicate, object]
end

#register_query(query) ⇒ Object 



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# File 'lib/grel/ql.rb', line 305

def register_query(query)
  @orig_query = query
  query.each_pair do |k,v|
    @query_keys << k if(k != :@id && k.to_s.index("$inv_").nil?)
  end
  self
end

#required_properties ⇒ Object 



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# File 'lib/grel/ql.rb', line 500

def required_properties
  props = []
  
end

#run ⇒ Object 



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# File 'lib/grel/ql.rb', line 496

def run
  @graph.query(to_sparql_describe)
end

#to_sparql_describe(preamble = true) ⇒ Object 



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# File 'lib/grel/ql.rb', line 379

def to_sparql_describe(preamble=true)
  bgps = @triples.map{|t| 
    if(t.is_a?(Filter))
      t.acum
    else
      t.join(' ') 
    end
  }.join(" . ")

  optional_bgps = @optional_bgps.map{|optional_triples| 
    "OPTIONAL { "+ optional_triples.map { |t|
      if(t.is_a?(Filter))
        t.acum
      else
        t.join(' ') 
      end
    }.join(" . ") + " }"
  }.join(" ")

  main_bgp = "#{bgps}"
  unless(@optional_bgps.empty?)
    main_bgp += " #{optional_bgps}"
  end

  query = if(preamble)
    query = "PREFIX : <http://grel.org/vocabulary#> PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> PREFIX rdfs: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>"
    query = query + " PREFIX xsd: <http://www.w3.org/2001/XMLSchema#> PREFIX fn: <http://www.w3.org/2005/xpath-functions#> " 

    if(@unions.length>0)
      union_bgps = @unions.map{|u| u.to_sparql_describe(false) }.join(" UNION ")
      union_projections = @unions.map{|u| u.projection.keys }.flatten.uniq
      all_subjects = (@projection.keys + union_projections).uniq
      query += "DESCRIBE #{all_subjects.join(' ')} WHERE { { #{main_bgp} } UNION #{union_bgps} }"            
    else
      query += "DESCRIBE #{@projection.keys.join(' ')} WHERE { #{main_bgp} }"
    end
  else
    "{ #{main_bgp} }"
  end
end

#to_sparql_select(preamble = true) ⇒ Object 



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# File 'lib/grel/ql.rb', line 420

def to_sparql_select(preamble=true)

  projection = {}

  bgps = @triples.map{ |t| 
    s,p,o = t
    if(s.to_s.index("?X_") == 0 && p.to_s.index("?X_") == 0 && o.to_s.index("?X_") == 0)
    elsif(s.to_s.index("?S_mg") == 0 && p.to_s.index("?P_mg") == 0 && o.to_s.index("?O_mg") == 0)
      nil
    else
      projection[s] = true if((s.to_s.index("?") == 0) && s.to_s.index("?X_").nil? && s.index("_mg_").nil?)  
      projection[p] = true if((p.to_s.index("?") == 0) && p.to_s.index("?X_").nil? && p.index("_mg_").nil?) 
      projection[o] = true if((o.to_s.index("?") == 0) && o.to_s.index("?X_").nil? && o.index("_mg_").nil?) 
      if(t.is_a?(Filter))
        t.acum
      else
        t.join(' ') 
      end
    end
  }.compact.join(" . ")

  optional_bgps = @optional_bgps.map{|optional_triples| 
    "OPTIONAL { "+ optional_triples.map { |t|
      s,p,o = t
      if(s.to_s.index("?") == 0 && p.to_s.index("?") == 0 && o.to_s.index("?") == 0)
        nil
      else
        projection[s] = true if((s.to_s.index("?") == 0) && s.to_s.index("?X_").nil?)  
        projection[p] = true if((p.to_s.index("?") == 0) && p.to_s.index("?X_").nil?) 
        projection[o] = true if((o.to_s.index("?") == 0) && o.to_s.index("?X_").nil?) 
        if(t.is_a?(Filter))
          t.acum
        else
          t.join(' ') 
        end
      end
    }.compact.join(" . ") + " }"
  }.join(" ")

  main_bgp = "#{bgps}"
  unless(@optional_bgps.empty?)
    main_bgp += " #{optional_bgps}"
  end

  query = if(preamble)
    query = "PREFIX : <http://grel.org/vocabulary#> PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> PREFIX rdfs: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>"
    query = query + " PREFIX xsd: <http://www.w3.org/2001/XMLSchema#> PREFIX fn: <http://www.w3.org/2005/xpath-functions#> " 

    if(@unions.length>0)
      union_bgps = @unions.map{|u| u.to_sparql_describe(false) }.join(" UNION ")
      all_subjects = projection.keys
      query += "SELECT DISTINCT #{all_subjects.join(' ')} WHERE { { #{main_bgp} } UNION #{union_bgps} }"            
    else
      all_subjects = projection.keys
      query += "SELECT DISTINCT #{all_subjects.join(' ')} WHERE { #{main_bgp} }"
    end
  else
    "{ #{main_bgp} }"
  end
end

#union(other_context) ⇒ Object 



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# File 'lib/grel/ql.rb', line 491

def union(other_context)
  @unions << other_context
  self
end