Class: ActiveFedora::Associations::Association

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

Overview

This is the root class of all associations:

Association
  BelongsToAssociation
  AssociationCollection
    HasManyAssociation

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(owner, reflection) ⇒ Association

Returns a new instance of Association



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# File 'lib/active_fedora/associations/association.rb', line 16

def initialize(owner, reflection)
  reflection.check_validity!
  @owner, @reflection = owner, reflection
  reset
  # construct_scope
end

Instance Attribute Details

#inversedObject

Returns the value of attribute inversed



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# File 'lib/active_fedora/associations/association.rb', line 13

def inversed
  @inversed
end

#ownerObject (readonly)

Returns the value of attribute owner



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# File 'lib/active_fedora/associations/association.rb', line 12

def owner
  @owner
end

#reflectionObject (readonly)

Returns the value of attribute reflection



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# File 'lib/active_fedora/associations/association.rb', line 12

def reflection
  @reflection
end

#targetObject

Returns the value of attribute target



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# File 'lib/active_fedora/associations/association.rb', line 12

def target
  @target
end

Instance Method Details

#association_scopeObject

The scope for this association.

Note that the association_scope is merged into the target_scope only when the scope method is called. This is because at that point the call may be surrounded by scope.scoping { … } or with_scope { … } etc, which affects the scope which actually gets built.



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# File 'lib/active_fedora/associations/association.rb', line 76

def association_scope
  if klass
    @association_scope ||= AssociationScope.new(self).scope
  end
end

#initialize_attributes(record) ⇒ Object

:nodoc:



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# File 'lib/active_fedora/associations/association.rb', line 118

def initialize_attributes(record) #:nodoc:
  skip_assign = [reflection.foreign_key].compact
  attributes = create_scope.except(*(record.changed - skip_assign))
  record.attributes = attributes
  set_inverse_instance(record)
end

#load_targetObject

Loads the target if needed and returns it.

This method is abstract in the sense that it relies on find_target, which is expected to be provided by descendants.

If the target is already loaded it is just returned. Thus, you can call load_target unconditionally to get the target.

ActiveFedora::ObjectNotFoundError is rescued within the method, and it is not reraised. The proxy is reset and nil is the return value.



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# File 'lib/active_fedora/associations/association.rb', line 112

def load_target
  @target = find_target if (@stale_state && stale_target?) || find_target?
  loaded! unless loaded?
  target
end

#loaded!Object

Asserts the target has been loaded setting the loaded flag to true.



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# File 'lib/active_fedora/associations/association.rb', line 44

def loaded!
  @loaded = true
  @stale_state = stale_state
  @inversed = false
end

#loaded?Boolean

Has the target been already loaded?

Returns:

  • (Boolean)


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# File 'lib/active_fedora/associations/association.rb', line 39

def loaded?
  @loaded
end

#reloadObject

Reloads the target and returns self on success.



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

def reload
  reset
  # construct_scope
  load_target
  self unless @target.nil?
end

#resetObject

Resets the loaded flag to false and sets the target to nil.



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# File 'lib/active_fedora/associations/association.rb', line 24

def reset
  @loaded = false
  @target = nil
  @inversed = false
end

#scopeObject



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# File 'lib/active_fedora/associations/association.rb', line 66

def scope
  target_scope.merge(association_scope)
end

#set_inverse_instance(record) ⇒ Object

Set the inverse association, if possible



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# File 'lib/active_fedora/associations/association.rb', line 83

def set_inverse_instance(record)
  if record && invertible_for?(record)
    inverse = record.association(inverse_reflection_for(record).name.to_sym)
    if inverse.is_a? ActiveFedora::Associations::HasAndBelongsToManyAssociation
      inverse.target << owner
    else
      inverse.target = owner
    end
    inverse.inversed = true
  end
end

#stale_target?Boolean

The target is stale if the target no longer points to the record(s) that the relevant foreign_key(s) refers to. If stale, the association accessor method on the owner will reload the target. It's up to subclasses to implement the state_state method if relevant.

Note that if the target has not been loaded, it is not considered stale.

Returns:

  • (Boolean)


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# File 'lib/active_fedora/associations/association.rb', line 56

def stale_target?
  !inversed && loaded? && @stale_state != stale_state
end

#target_scopeObject

Can be overridden (i.e. in ThroughAssociation) to merge in other scopes (i.e. the through association's scope)



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# File 'lib/active_fedora/associations/association.rb', line 98

def target_scope
  klass.all
end