Module: Shanty::Mixins::ActsAsLinkGraphNode

Included in:
Project
Defined in:
lib/shanty/mixins/acts_as_link_graph_node.rb

Overview

A mixin module enabling classes to have parents and children. It provides convenience methods for determining dependencies, depdenants, and a distance from the root node. Note that in contrast to a tree, this link graph module allows multiple parents.

Defined Under Namespace

Modules: ClassMethods

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.included(cls) ⇒ Object

The self.included idiom. This is described in great detail in a fantastic blog post here:

www.railstips.org/blog/archives/2009/05/15/include-vs-extend-in-ruby/

Basically, this idiom allows us to add both instance and class methods to the class that is mixing this module into itself without forcing them to call extend and include for this mixin. You’ll see this idiom everywhere in the Ruby/Rails world, so we use it too.



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# File 'lib/shanty/mixins/acts_as_link_graph_node.rb', line 17

def self.included(cls)
  cls.extend(ClassMethods)
end

Instance Method Details

#add_child(node) ⇒ Object

Public: Add a node to the children linked to this instance.

node - The Object to add.



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# File 'lib/shanty/mixins/acts_as_link_graph_node.rb', line 50

def add_child(node)
  children << node
end

#add_parent(node) ⇒ Object

Public: Add a node to the parents linked to this instance.

node - The Object to add.



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# File 'lib/shanty/mixins/acts_as_link_graph_node.rb', line 43

def add_parent(node)
  parents << node
end

#all_children ⇒ Object

Public: Convenience method to return all of the children from this node in the tree downwards to the leaves of the tree.

Returns an Array of child Objects.



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# File 'lib/shanty/mixins/acts_as_link_graph_node.rb', line 58

def all_children
  children + children.map(&:all_children).flatten
end

#all_parents ⇒ Object

Public: Convenience method to return all of the parents from this node in the tree upwards to the root of the tree.

Returns an Array of parent Objects.



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# File 'lib/shanty/mixins/acts_as_link_graph_node.rb', line 66

def all_parents
  parents + parents.map(&:all_parents).flatten
end

#children ⇒ Object

Public: The children linked to this instance.

Returns an Array of Objects.



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# File 'lib/shanty/mixins/acts_as_link_graph_node.rb', line 36

def children
  @children ||= []
end

#parents ⇒ Object

Public: The parents linked to this instance.

Returns an Array of Objects.



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# File 'lib/shanty/mixins/acts_as_link_graph_node.rb', line 29

def parents
  @parents ||= []
end