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

Inherits:
Object
  • Object
show all
Defined in:
activerecord/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 'activerecord/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

#klassObject (readonly)

Returns the value of attribute klass


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

def klass
  @klass
end

#modelObject (readonly)

Returns the value of attribute model


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

def model
  @model
end

#ownersObject (readonly)

Returns the value of attribute owners


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

def owners
  @owners
end

#preload_scopeObject (readonly)

Returns the value of attribute preload_scope


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

def preload_scope
  @preload_scope
end

#reflectionObject (readonly)

Returns the value of attribute reflection


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

def reflection
  @reflection
end

Instance Method Details

#association_keyObject

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


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

def association_key
  table[association_key_name]
end

#association_key_nameObject

The name of the key on the associated records

Raises:

  • (NotImplementedError)

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

def association_key_name
  raise NotImplementedError
end

#optionsObject


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

def options
  reflection.options
end

#owner_key_nameObject

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

Raises:

  • (NotImplementedError)

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

def owner_key_name
  raise NotImplementedError
end

#owners_by_keyObject

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 'activerecord/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

#preloadObject

Raises:

  • (NotImplementedError)

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

def preload
  raise NotImplementedError
end

#records_for(ids) ⇒ Object


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

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

#runObject


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

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

#scopeObject


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

def scope
  @scope ||= build_scope
end

#tableObject


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

def table
  klass.arel_table
end