Class: MiniGauge::Graph

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

Overview

From Railroad, an object to hold our nodes and edges, also to export them on demand

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(opts = {}) ⇒ Graph 



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# File 'lib/mini_gauge.rb', line 90

def initialize(opts = {})
  @graph_type = opts[:graph_type] || 'Model'
  @show_label = opts[:show_label] || true
  @title = opts[:title] || "#{@graph_type} diagram"
  @description = opts[:description] || ''
  @nodes = []
  @edges = []
  
  # Designed to work with the other class and instance methods on AR objects
  # to make adding nodes and edges easier.  Allows you to do something like
  # @graph.nodes << Invoice.first
  @nodes.instance_eval(%Q(
    def <<(item)
      if item.respond_to?(:dot_node_definition)
        super(item.dot_node_definition)
      else
        super(item)
      end
    end
  ))
  
  # Makes building graphs easier, allows you to do something like
  # @graph.edges << {:source => Person.first, :destination => Person.first.organization}
  @edges.instance_eval(%Q(
    def <<(item)
      if item.is_a? Hash
        if item[:source] && item[:source].respond_to?(:dot_node_name)
          item[:source] = item[:source].dot_node_name
        end
        
        if item[:destination] && item[:destination].respond_to?(:dot_node_name)
          item[:destination] = item[:destination].dot_node_name
        end
      end
      super(item)
    end
  ))
  
end

Instance Attribute Details

#description ⇒ Object

Returns the value of attribute description.



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# File 'lib/mini_gauge.rb', line 88

def description
  @description
end

#edges ⇒ Object

Returns the value of attribute edges.



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# File 'lib/mini_gauge.rb', line 88

def edges
  @edges
end

#graph_type ⇒ Object

Returns the value of attribute graph_type.



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# File 'lib/mini_gauge.rb', line 88

def graph_type
  @graph_type
end

#nodes ⇒ Object

Returns the value of attribute nodes.



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# File 'lib/mini_gauge.rb', line 88

def nodes
  @nodes
end

#show_label ⇒ Object

Returns the value of attribute show_label.



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# File 'lib/mini_gauge.rb', line 88

def show_label
  @show_label
end

#title ⇒ Object

Returns the value of attribute title.



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# File 'lib/mini_gauge.rb', line 88

def title
  @title
end

Instance Method Details

#add(opts) ⇒ Object

Add an item to the graph, expects a source node and destination node or a label if there is no destination

Raises:

  • (ArgumentError) 


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# File 'lib/mini_gauge.rb', line 131

def add(opts)
  raise ArgumentError.new("Must supply :source and :destination") unless opts.is_a?(Hash) && opts.keys.include?(:source) && opts.keys.include?(:destination)
  raise ArgumentError.new("Cannot supply a nil :destination without a label") if opts[:destination].nil? && opts[:label].nil?
  
  if opts[:destination].nil?
    node_name = "#{opts[:label].underscore}_#{opts.object_id}"
    @nodes << self.nil_node_definition(:label => opts[:label], :name => node_name)
    @edges << {:destination => node_name, :source => opts[:source], :empty_rec => true}
  else
    @nodes<<opts[:source] unless @nodes.any?{|x| opts[:source].dot_node_name == x[:name] }
    @nodes<<opts[:destination] unless @nodes.any?{|x| opts[:destination].dot_node_name == x[:name] }
    @edges<<opts
  end
end

#dot_label ⇒ Object

Build diagram label



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# File 'lib/mini_gauge.rb', line 170

def dot_label
  return "\t_diagram_info [shape=\"plaintext\", " +
         "label=\"#{@title} \\l" +
         "Date: #{Time.now.strftime "%b %d %Y - %H:%M"}\\l" + 
         "Migration version: " +
         "#{ActiveRecord::Migrator.current_version}\\l" +
         "Description: #{@description}\\l" + 
         "\\l\", fontsize=14]\n"
end

#format_edge(edge) ⇒ Object

Take an edge (hash) and format it into dot notation



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# File 'lib/mini_gauge.rb', line 190

def format_edge(edge)
  edge[:options] ||= {}
  edge[:options][:label] = edge[:label] unless edge[:label].blank?
  edge[:options].merge!({:style => "dotted", :color => "gray61"}) if edge[:empty_rec]
  case edge[:type]
    when 'one-one'
         edge[:options].merge!({:arrowtail => "odot", :arrowhead => "dot", :dir => "both"})
    when 'one-many'
         edge[:options].merge!({:arrowtail => "crow", :arrowhead => "dot", :dir => "both"})
    when 'many-many'
         edge[:options].merge!({:arrowtail => "crow", :arrowhead => "crow", :dir => "both"})
    when 'is-a'
         edge[:options].merge!({:arrowtail => "onormal", :arrowhead => "none"})
  end
  opts = edge[:options].collect{|k,v| %Q(#{k}="#{v}") }.join(", ")
  return %Q( "#{edge[:source]}" -> "#{edge[:destination]}" [#{opts}]\n )
end

#format_node(node) ⇒ Object

Take a node (hash) and format it into dot notation



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# File 'lib/mini_gauge.rb', line 181

def format_node(node)
  node[:options] ||= {}
  node[:options][:shape] = "Mrecord"
  node[:options][:label] = %Q({#{(node[:label] || node[:name])} | #{node[:attributes].join('\l')} \\l} )
  opts = node[:options].collect{|k,v| %Q(#{k}="#{v}") }.join(", ")
  return %Q(\t"#{node[:name]}" [#{opts}]\n)
end

#nil_node_definition(opts) ⇒ Object

Returns a node definition for an empty node

Raises:

  • (ArgumentError) 


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# File 'lib/mini_gauge.rb', line 147

def nil_node_definition(opts)
  raise ArgumentError.new("Must supply at least :name or :label") unless opts.is_a?(Hash) && (opts.keys.include?(:name) || opts.keys.include?(:label))
  
  {:name => (opts[:name] || opts[:label].underscore), :label => (opts[:label] || opts[:name].humanize.titleize), :attributes => ["none"], :options => {:color => "gray61"}}
end

#to_dot_notation ⇒ Object

Returns a string representing the DOT graph



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# File 'lib/mini_gauge.rb', line 154

def to_dot_notation
  header = "digraph #{@graph_type.downcase}_diagram {\n" +
           "\tgraph[overlap=false, splines=true]\n"
  header += dot_label if @show_label
  
  uniq_nodes = @nodes.inject([]) { |result,h| result << h unless result.include?(h); result }
  uniq_edges = @edges.inject([]) { |result,h| result << h unless result.include?(h); result }
  
  return header +
         uniq_nodes.map{|node| format_node(node)}.to_s + "\n" + 
         uniq_edges.map{|edge| format_edge(edge)}.to_s +
         "}\n"
end