Class: Mongoid::Association::Eager

Inherits:

Object

• Object
• Mongoid::Association::Eager

Defined in:

lib/mongoid/association/eager.rb

Overview

Base class for eager load preload functions.

Direct Known Subclasses

Referenced::BelongsTo::Eager, Referenced::HasAndBelongsToMany::Eager, Referenced::HasMany::Eager, Referenced::HasManyThrough::Eager, Referenced::HasOne::Eager, Referenced::HasOneThrough::Eager

Class Method Summary

• .run(associations, docs, use_lookup = false, pipeline = []) ⇒ Array

  Build a preloader for the given arguments and run it.

Instance Method Summary

• #initialize(associations, docs, use_lookup = false, pipeline = []) ⇒ Base constructor

  Instantiate the eager load class.

• #run ⇒ Array

  Run the preloader.

Constructor Details

#initialize(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.

# File 'lib/mongoid/association/eager.rb', line 30

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

Class Method Details

.run(associations, docs, use_lookup = false, pipeline = []) ⇒ Array

Build a preloader for the given arguments and run it.

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.

Returns:

• (Array) —

  The list of documents given.

# File 'lib/mongoid/association/eager.rb', line 12

def self.run(associations, docs, use_lookup = false, pipeline = [])
  new(associations, docs, use_lookup, pipeline).run
end

Instance Method Details

#run ⇒ Array

Run the preloader.

Examples:

Preload the associations into the documents.

loader.run

Returns:

• (Array) —

  The list of documents given.

# File 'lib/mongoid/association/eager.rb', line 44

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