Class: ActiveRecord::Associations::Preloader::Association

Inherits:
Object
  • Object
show all
Defined in:
lib/active_record/associations/preloader/association.rb

Overview

:nodoc:

Direct Known Subclasses

CollectionAssociation, SingularAssociation

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(klass, owners, reflection, preload_scope) ⇒ Association

Returns a new instance of Association.



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# File 'lib/active_record/associations/preloader/association.rb', line 7

def initialize(klass, owners, reflection, preload_scope)
  @klass         = klass
  @owners        = owners
  @reflection    = reflection
  @preload_scope = preload_scope
  @model         = owners.first && owners.first.class
  @scope         = nil
  @owners_by_key = nil
end

Instance Attribute Details

#klass ⇒ Object (readonly)

Returns the value of attribute klass.



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# File 'lib/active_record/associations/preloader/association.rb', line 5

def klass
  @klass
end

#model ⇒ Object (readonly)

Returns the value of attribute model.



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# File 'lib/active_record/associations/preloader/association.rb', line 5

def model
  @model
end

#owners ⇒ Object (readonly)

Returns the value of attribute owners.



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# File 'lib/active_record/associations/preloader/association.rb', line 5

def owners
  @owners
end

#preload_scope ⇒ Object (readonly)

Returns the value of attribute preload_scope.



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# File 'lib/active_record/associations/preloader/association.rb', line 5

def preload_scope
  @preload_scope
end

#reflection ⇒ Object (readonly)

Returns the value of attribute reflection.



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# File 'lib/active_record/associations/preloader/association.rb', line 5

def reflection
  @reflection
end

Instance Method Details

#association_key ⇒ Object

This is overridden by HABTM as the condition should be on the foreign_key column in the join table



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# File 'lib/active_record/associations/preloader/association.rb', line 46

def association_key
  table[association_key_name]
end

#association_key_name ⇒ Object

The name of the key on the associated records

Raises:

  • (NotImplementedError) 


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# File 'lib/active_record/associations/preloader/association.rb', line 40

def association_key_name
  raise NotImplementedError
end

#options ⇒ Object 



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# File 'lib/active_record/associations/preloader/association.rb', line 64

def options
  reflection.options
end

#owner_key_name ⇒ Object

The name of the key on the model which declares the association

Raises:

  • (NotImplementedError) 


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# File 'lib/active_record/associations/preloader/association.rb', line 51

def owner_key_name
  raise NotImplementedError
end

#owners_by_key ⇒ Object

We’re converting to a string here because postgres will return the aliased association key in a habtm as a string (for whatever reason)



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# File 'lib/active_record/associations/preloader/association.rb', line 57

def owners_by_key
  @owners_by_key ||= owners.group_by do |owner|
    key = owner[owner_key_name]
    key && key.to_s
  end
end

#preload ⇒ Object

Raises:

  • (NotImplementedError) 


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# File 'lib/active_record/associations/preloader/association.rb', line 23

def preload
  raise NotImplementedError
end

#records_for(ids) ⇒ Object 



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# File 'lib/active_record/associations/preloader/association.rb', line 31

def records_for(ids)
  scope.where(association_key.in(ids))
end

#run ⇒ Object 



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# File 'lib/active_record/associations/preloader/association.rb', line 17

def run
  unless owners.first.association(reflection.name).loaded?
    preload
  end
end

#scope ⇒ Object 



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# File 'lib/active_record/associations/preloader/association.rb', line 27

def scope
  @scope ||= build_scope
end

#table ⇒ Object 



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# File 'lib/active_record/associations/preloader/association.rb', line 35

def table
  klass.arel_table
end