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Class: Mongoid::Association::Eager

Relationships & Source Files
Extension / Inclusion / Inheritance Descendants
Subclasses:
Mongoid::Association::Embedded::Eager, Referenced::BelongsTo::Eager, Referenced::HasAndBelongsToMany::Eager, Referenced::HasMany::Eager, Referenced::HasOne::Eager
Inherits: Object
Defined in: lib/mongoid/association/eager.rb

Overview

Base class for eager load preload functions.

Class Method Summary

Instance Method Summary

Constructor Details

.new(associations, docs, use_lookup = false, pipeline = []) ⇒ Base

Instantiate the eager load class.

Examples:

Create the new belongs to eager load preloader.

BelongsTo.new(association, parent_docs)

Parameters:

  • associations (Array<Mongoid::Association::Relatable>) —

    Associations to eager load

  • docs (Array<Document>) —

    Documents to preload the associations

  • use_lookup (Boolean) (defaults to: false) —

    Whether to use $lookup aggregation for eager loading. This is used in Criteria#eager_load.

  • pipeline (Array<Hash>) (defaults to: []) —

    The aggregation pipeline to use when using $lookup for eager loading.

[ GitHub ] 

  


# File 'lib/mongoid/association/eager.rb', line 23



def initialize(associations, docs, use_lookup = false, pipeline = [])
  @associations = associations
  @docs = docs
  @grouped_docs = {}
  @use_lookup = use_lookup
  @pipeline = pipeline
end


  







Instance Method Details



  

    #each_loaded_document_of_class(cls, keys)   (private)
  



  

    

Retrieves the documents of the specified class, that have the foreign key included in the specified list of keys.



When the documents are retrieved, the set of inclusions applied is the set of inclusions applied to the host document minus the association that is being eagerly loaded.


  



  [ GitHub ]


  

  


# File 'lib/mongoid/association/eager.rb', line 95



private def each_loaded_document_of_class(cls, keys)
  # Note: keys should not include nil elements.
  # Upstream code is responsible for eliminating nils from keys.
  return cls.none if keys.empty?

  criteria = prepare_criteria_for_loaded_documents(cls, keys)
  criteria.each do |doc|
    yield doc
  end
end


  








  

    #prepare_criteria_for_loaded_documents(cls, keys)   (private)
  



  

    

Prepares the criteria to retrieve the documents of the specified class, that have the foreign key included in the specified list of keys. When the documents are retrieved, the set of inclusions applied is the set of inclusions applied to the host document minus the association that is being eagerly loaded.


  



  [ GitHub ]


  

  


# File 'lib/mongoid/association/eager.rb', line 189



def prepare_criteria_for_loaded_documents(cls, keys)
  criteria = cls.criteria
  criteria = criteria.apply_scope(@association.scope)
  criteria = criteria.any_in(key => keys)
  criteria.inclusions = criteria.inclusions - [@association]
  criteria
end


  








  

    #run  ⇒ Array 
  



  

    

Run the preloader.


  





    

    
Examples:

        


Preload the associations into the documents.



      
loader.run

  


Returns:


    
  
  • 
    (Array)
—    
    

    The list of documents given.
    

    
  
    • 





  [ GitHub ]


  

  


# File 'lib/mongoid/association/eager.rb', line 37



def run
  @loaded = []

  if @use_lookup
    preload_with_lookup
    @loaded = @docs
    return @loaded.flatten
  end

  while shift_association
    preload
    @loaded << @docs.collect { |d| d.send(@association.name) if d.respond_to?(@association.name) }
  end
  @loaded.flatten
end


  








  

    #shift_association  ⇒ Mongoid::Association::Relatable  (private)
  



  

    

Shift the current association metadata


  





    

    
Examples:

        


Shift the current association.



      
loader.shift_association

  


Returns:





  [ GitHub ]


  

  


# File 'lib/mongoid/association/eager.rb', line 180



def shift_association
  @association = @associations.shift
end