Class: Ruleby::Core::TerminalNode

Inherits:
Node show all
Defined in:
lib/core/nodes.rb

Overview

This class represents the bottom node in the network. There is a one to one relation between TerminalNodes and Rules. A terminal node acts as a wrapper for a rule. The class is responsible for keeping a memory of the activations that have been generated by the network.

Instance Attribute Summary

Attributes inherited from Printable

#parent_nodes

Instance Method Summary collapse

Methods inherited from Node

#resolve

Methods inherited from Printable

#print

Constructor Details

#initialize(bucket, rule) ⇒ TerminalNode

Returns a new instance of TerminalNode.



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# File 'lib/core/nodes.rb', line 912

def initialize(bucket, rule)
  super(bucket)
  @rule = rule
  @activations = MultiHash.new  
end

Instance Method Details

#activations ⇒ Object

attr_reader:activations



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# File 'lib/core/nodes.rb', line 919

def activations
  @activations
end

#assert(context) ⇒ Object 



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# File 'lib/core/nodes.rb', line 923

def assert(context)
  match = context.match
  a = Activation.new(@rule.action, match, @bucket.counter)
  @activations.add match.fact_ids, a
end

#modify(context) ⇒ Object 



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# File 'lib/core/nodes.rb', line 929

def modify(context)
  found = false
  @activations.each do |id, v|
    if context.match.fact_ids.sort == id.sort
      v.modify(context.match)
      found = true
    end
  end
  if !found and context.match.is_match
    assert(context)
  end
end

#retract(fact) ⇒ Object 



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# File 'lib/core/nodes.rb', line 942

def retract(fact)
  @activations.remove fact.id
end

#retract_resolve(match) ⇒ Object 



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# File 'lib/core/nodes.rb', line 954

def retract_resolve(match)
  # in this method we retract an existing activation from memory if its 
  # match resolves with the match given.  It would probably be better to 
  # check if it resolves with a list of facts.  But the system is not set up
  # for that yet.
  @activations.delete_if do |activation|
    resolve(activation.match, match)
  end
end

#satisfied? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/core/nodes.rb', line 946

def satisfied?
  return !@activations.values.empty? 
end

#to_s ⇒ Object 



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# File 'lib/core/nodes.rb', line 950

def to_s
  return "TerminalNode:#{object_id} | #{@activations.values}"
end