Class: Agama::Traverser

Inherits:
Object
  • Object
show all
Defined in:
lib/agama/traverser.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(db, graph) ⇒ Traverser

Returns a new instance of Traverser.



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# File 'lib/agama/traverser.rb', line 6

def initialize(db, graph)
  @cursor = db.e_cursor
  @search_key = ""
  @unset = true
  @graph = graph
  @from = nil
  @params = {}
end

Instance Attribute Details

#params ⇒ Object

Returns the value of attribute params.



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# File 'lib/agama/traverser.rb', line 4

def params
  @params
end

Instance Method Details

#along(edge_type) ⇒ Object 



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# File 'lib/agama/traverser.rb', line 20

def along(edge_type)
  self.set(:edge_type => edge_type)
end

#each ⇒ Object 



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# File 'lib/agama/traverser.rb', line 45

def each
  search_key = ""
  from = nil
  if @unset
    search_key = Keyify.range(@params)
    from = @graph.get_node(@params[:from])

    @cursor.jump(search_key)
    @unset = false
  end

  while @cursor.key and Keyify.subkey?(search_key, @cursor.key)
    to, type, direction, directed = Keyify.parse(@cursor.key)

    if @cursor.value
      new_edge = Marshal.load(@cursor.value)
      new_edge[:type] = type
      new_edge[:directed] = directed
      if direction == "I"
        new_edge[:to] = from
        new_edge[:from] = @graph.get_node(to)
      else
        new_edge[:from] = from
        new_edge[:to] = @graph.get_node(to)
      end
      yield new_edge
    end

    @cursor.next
  end
end

#incoming ⇒ Object 



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# File 'lib/agama/traverser.rb', line 29

def incoming
  self.set(:edge_type => Config::DEFAULT_TYPE) unless @params[:edge_type]
  self.set(:direction => "I")
end

#of_type(node_type) ⇒ Object 



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# File 'lib/agama/traverser.rb', line 39

def of_type(node_type)
  self.set(:edge_type => Config::DEFAULT_TYPE) unless @params[:edge_type]
  self.set(:direction => "N") unless @params[:direction]
  self.set(:to_type => node_type)
end

#outgoing ⇒ Object 



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# File 'lib/agama/traverser.rb', line 24

def outgoing
  self.set(:edge_type => Config::DEFAULT_TYPE) unless @params[:edge_type]
  self.set(:direction => "O")
end

#set(params) ⇒ Object 



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# File 'lib/agama/traverser.rb', line 15

def set(params)
  @params.merge!(params)
  self
end

#undirected ⇒ Object 



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# File 'lib/agama/traverser.rb', line 34

def undirected
  self.set(:edge_type => Config::DEFAULT_TYPE) unless @params[:edge_type]
  self.set(:direction => "N")
end