Module: Ritsu::Utility::InstanceDependencies::ClassMethods

Defined in:
lib/ritsu/utility/instance_dependencies.rb

Instance Method Summary collapse

Instance Method Details

#dependencies_between(name) ⇒ Object



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# File 'lib/ritsu/utility/instance_dependencies.rb', line 14

def dependencies_between(name)
  name = name.to_s.singularize
  dependency_set_name = "dependency_#{name.pluralize}"
  
  module_eval "    attr_reader :\#{dependency_set_name}\n    attr_accessor :topological_order\n    \n    def \#{dependency_set_name}\n      @\#{dependency_set_name} ||= Ritsu::Utility::CheckUponAddSet.new do |s,dependency|\n        validate_dependency_\#{name}(dependency)\n        self.class.invalidate_topological_orders\n      end\n    end\n    \n    def depends_directly_on_\#{name}?(instance)\n      \#{dependency_set_name}.include?(instance)\n    end\n    \n    def depends_on_\#{name}?(instance)\n      visited = Set.new [self]\n      queue = [self]\n\n      # Perform a breadth first search\n      while !visited.include?(instance) && !queue.empty?\n        u = queue.shift\n        u.\#{dependency_set_name}.each do |v|\n          if !visited.include?(v)\n            queue << v\n            visited << v\n          end\n        end\n      end\n\n      visited.delete(self)\n      visited.include?(instance)\n    end\n    \n    def validate_dependency_\#{name}(instance)\n      instance_name = instance.name\n      if instance == self\n        raise ArgumentError.new(\"'\\\#{instance.name}' is the same as the dependent \#{name}\")\n      end\n      if instance.depends_on_\#{name}?(self)\n        raise ArgumentError.new(\"including '\\\#{instance.name}' will create a circular dependency\")\n      end\n      if !instance.can_be_depended_on?\n        raise ArgumentError.new(\"'\\\#{instance.name}' cannot be dependend on\")\n      end\n    end\n    \n    def self.recompute_topological_orders\n      indegrees = {}\n      instances.each { |instance| indegrees[instance] = 0 }\n      instances.each do |instance|\n        instance.\#{dependency_set_name}.each do |dependency|\n          indegrees[dependency] += 1\n        end\n      end\n\n      last_order = instances.length-1\n      indegree_zero = instances.select { |instance| indegrees[instance] == 0 }\n      while !indegree_zero.empty?\n        u = indegree_zero.shift\n        u.topological_order = last_order\n        last_order -= 1\n        u.\#{dependency_set_name}.each do |v|\n          indegrees[v] -= 1\n          if indegrees[v] == 0\n            indegree_zero << v\n          end\n        end\n      end\n      \n      @topological_orders_computed = true\n    end\n    \n    def self.topological_orders_computed?\n      @topological_order_computed ||= false\n    end\n\n    def self.compute_topological_orders\n      if !topological_orders_computed?\n        recompute_topological_orders\n      end\n    end\n\n    def self.invalidate_topological_orders\n      @topological_order_computed = false\n    end\n    \n    def can_be_depended_on?\n      raise NotImplementedError.new\n    end\n  RUBY\nend\n"