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Class: Mongo::Collection::View::Builder::MapReduce

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Class Chain:
self, Forwardable
Inherits: Object
Defined in: lib/mongo/collection/view/builder/map_reduce.rb

Overview

Builds a map/reduce specification from the view and options.

Since:

  • 2.2.0

Constant Summary

  • MAPPINGS =

    The mappings from ruby options to the map/reduce options.

    Since:

    • 2.2.0

    # File 'lib/mongo/collection/view/builder/map_reduce.rb', line 32 
    BSON::Document.new(
  finalize: 'finalize',
  js_mode: 'jsMode',
  out: 'out',
  scope: 'scope',
  verbose: 'verbose',
  bypass_document_validation: 'bypassDocumentValidation',
  collation: 'collation',
).freeze

Class Method Summary

Instance Attribute Summary

Instance Method Summary

Constructor Details

.new(map, reduce, view, options) ⇒ MapReduce

Initialize the builder.

Examples:

Initialize the builder.

MapReduce.new(map, reduce, view, options)

Parameters:

  • map (String) —

    The map function.

  • reduce (String) —

    The reduce function.

  • view (Collection::View) —

    The collection view.

  • options (Hash) —

    The map/reduce options.

Since:

  • 2.2.0

[ GitHub ] 

  


# File 'lib/mongo/collection/view/builder/map_reduce.rb', line 67



def initialize(map, reduce, view, options)
  @map = map
  @reduce = reduce
  @view = view
  @options = options
end


  







Instance Attribute Details



  

    #map  ⇒ String  (readonly)
  



  

    
  





  
Returns:


    
  
  • 
    (String)
—    
    

    map The map function.
    

    
  
    • 



Since:


    
  
  • 
    
    

    2.2.0
    

    
  
    • 





  [ GitHub ]


  

  


# File 'lib/mongo/collection/view/builder/map_reduce.rb', line 45



attr_reader :map


  








  

    #options  ⇒ Hash  (readonly)
  



  

    
  





  
Returns:


    
  
  • 
    (Hash)
—    
    

    options The map/reduce specific options.
    

    
  
    • 



Since:


    
  
  • 
    
    

    2.2.0
    

    
  
    • 





  [ GitHub ]


  

  


# File 'lib/mongo/collection/view/builder/map_reduce.rb', line 54



attr_reader :options


  








  

    #reduce  ⇒ String  (readonly)
  



  

    
  





  
Returns:


    
  
  • 
    (String)
—    
    

    reduce The reduce function.
    

    
  
    • 



Since:


    
  
  • 
    
    

    2.2.0
    

    
  
    • 





  [ GitHub ]


  

  


# File 'lib/mongo/collection/view/builder/map_reduce.rb', line 48



attr_reader :reduce


  








  

    #view  ⇒ Collection::View  (readonly)
  



  

    
  





  
Returns:



Since:


    
  
  • 
    
    

    2.2.0
    

    
  
    • 





  [ GitHub ]


  

  


# File 'lib/mongo/collection/view/builder/map_reduce.rb', line 51



attr_reader :view


  







Instance Method Details



  

    #map_reduce_command   (private)
  



  

    
  





  
Since:


    
  
  • 
    
    

    2.2.0
    

    
  
    • 





  [ GitHub ]


  

  


# File 'lib/mongo/collection/view/builder/map_reduce.rb', line 103



def map_reduce_command
  command = BSON::Document.new(
    :mapReduce => collection.name,
    :map => map,
    :reduce => reduce,
    :query => filter,
    :out => { inline: 1 },
  )
  # Shouldn't this use self.read ?
  if collection.read_concern
    command[:readConcern] = Options::Mapper.transform_values_to_strings(
      collection.read_concern)
  end
  command.update(view_options)
  command.update(options.slice(:collation))

  # Read preference isn't simply passed in the command payload
  # (it may need to be converted to wire protocol flags).
  # Ideally it should be removed here, however due to Mongoid 7
  # using this method and requiring :read to be returned from it,
  # we cannot do this just yet - see RUBY-2932.
  #command.delete(:read)

  command.merge!(Options::Mapper.transform_documents(options, MAPPINGS))
  command
end


  








  

    #specification  ⇒ Hash 
  



  

    

Get the specification to pass to the map/reduce operation.


  





    

    
Examples:

        


Get the specification.



      
builder.specification

  


Returns:


    
  
  • 
    (Hash)
—    
    

    The specification.
    

    
  
    • 



Since:


    
  
  • 
    
    

    2.2.0
    

    
  
    • 





  [ GitHub ]


  

  


# File 'lib/mongo/collection/view/builder/map_reduce.rb', line 82



def specification
  spec = {
    selector: map_reduce_command,
    db_name: database.name,
    # Note that selector just above may also have a read preference
    # specified, per the #map_reduce_command method below.
    read: read,
    session: options[:session]
  }
  write?(spec) ? spec.merge!(write_concern: write_concern) : spec
end


  








  

    #view_options   (private)
  



  

    
  





  
Since:


    
  
  • 
    
    

    2.2.0
    

    
  
    • 





  [ GitHub ]


  

  


# File 'lib/mongo/collection/view/builder/map_reduce.rb', line 130



def view_options
  @view_options ||= (opts = view.options.dup
                     opts.delete(:session)
                     opts)
end


  








  

    #write?(spec)  ⇒ Boolean  (private)
  



  

    
  





  
Since:


    
  
  • 
    
    

    2.2.0
    

    
  
    • 





  [ GitHub ]


  

  


# File 'lib/mongo/collection/view/builder/map_reduce.rb', line 96



def write?(spec)
  if out = spec[:selector][:out]
    out.is_a?(String) ||
      (out.respond_to?(:keys) && out.keys.first.to_s.downcase != View::MapReduce::INLINE)
  end
end