Class: ActiveEntity::Associations::Embeds::CollectionAssociation

Inherits:
Association
  • Object
show all
Defined in:
lib/active_entity/associations/embeds/collection_association.rb

Overview

Active Entity Association Collection

CollectionAssociation is an abstract class that provides common stuff to ease the implementation of association proxies that represent collections. See the class hierarchy in Association.

CollectionAssociation:
  HasManyAssociation => has_many
    HasManyThroughAssociation + ThroughAssociation => has_many :through

The CollectionAssociation class provides common methods to the collections defined by has_and_belongs_to_many, has_many or has_many with the :through association option.

You need to be careful with assumptions regarding the target: The proxy does not fetch records from the database until it needs them, but new ones created with build are added to the target. So, the target may be non-empty and still lack children waiting to be read from the database. If you look directly to the database you cannot assume that’s the entire collection because new records may have been added to the target, etc.

If you need to work on all current children, new and existing records, load_target and the loaded flag are your friends.

Direct Known Subclasses

EmbedsManyAssociation

Instance Attribute Summary

Attributes inherited from Association

#owner, #reflection, #target

Instance Method Summary collapse

Methods inherited from Association

#extensions, #initialize_attributes, #inversed_from, #klass, #loaded?, #marshal_dump, #marshal_load, #remove_inverse_instance, #set_inverse_instance

Constructor Details

#initialize(owner, reflection) ⇒ CollectionAssociation

:nodoc:



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# File 'lib/active_entity/associations/embeds/collection_association.rb', line 30

def initialize(owner, reflection)
  super

  @target = []
end

Instance Method Details

#add_to_target(record, skip_callbacks = false, &block) ⇒ Object 



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# File 'lib/active_entity/associations/embeds/collection_association.rb', line 151

def add_to_target(record, skip_callbacks = false, &block)
  # index = @target.index(record)
  # replace_on_target(record, index, skip_callbacks, &block)
  replace_on_target(record, nil, skip_callbacks, &block)
end

#build(attributes = {}, &block) ⇒ Object 



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# File 'lib/active_entity/associations/embeds/collection_association.rb', line 50

def build(attributes = {}, &block)
  if attributes.is_a?(Array)
    attributes.collect { |attr| build(attr, &block) }
  else
    add_to_target(build_record(attributes, &block))
  end
end

#concat(*records) ⇒ Object

Add records to this association. Returns self so method calls may be chained. Since << flattens its argument list and inserts each record, push and concat behave identically.



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# File 'lib/active_entity/associations/embeds/collection_association.rb', line 61

def concat(*records)
  records = records.flatten
  concat_records(records)
end

#delete(*records) ⇒ Object Also known as: destroy

Removes records from this association calling before_remove and after_remove callbacks.

This method is abstract in the sense that delete_records has to be provided by descendants. Note this method does not imply the records are actually removed from the database, that depends precisely on delete_records. They are in any case removed from the collection.



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# File 'lib/active_entity/associations/embeds/collection_association.rb', line 91

def delete(*records)
  records.each do |record|
    target.delete(record)
  end
end

#delete_all ⇒ Object Also known as: destroy_all

Removes all records from the association without calling callbacks on the associated records. It honors the :dependent option. However if the :dependent value is :destroy then in that case the :delete_all deletion strategy for the association is applied.

You can force a particular deletion strategy by passing a parameter.

Example:

@author.books.delete_all(:nullify) @author.books.delete_all(:delete_all)

See delete for more info.



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# File 'lib/active_entity/associations/embeds/collection_association.rb', line 79

def delete_all
  target.clear
end

#empty? ⇒ Boolean

Returns true if the collection is empty.

If the collection has been loaded it is equivalent to collection.size.zero?. If the collection has not been loaded, it is equivalent to collection.exists?. If the collection has not already been loaded and you are going to fetch the records anyway it is better to check collection.length.zero?.

Returns:

  • (Boolean) 


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# File 'lib/active_entity/associations/embeds/collection_association.rb', line 120

def empty?
  size.zero?
end

#find(&block) ⇒ Object 



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# File 'lib/active_entity/associations/embeds/collection_association.rb', line 46

def find(&block)
  target.find(&block)
end

#include?(record) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_entity/associations/embeds/collection_association.rb', line 143

def include?(record)
  if record.is_a?(reflection.klass)
    target.include?(record)
  else
    false
  end
end

#reader ⇒ Object

Implements the reader method, e.g. foo.items for Foo.has_many :items



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# File 'lib/active_entity/associations/embeds/collection_association.rb', line 37

def reader
  @proxy ||= CollectionProxy.new(klass, self)
end

#replace(other_array) ⇒ Object

Replace this collection with other_array. This will perform a diff and delete/add only records that have changed.



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# File 'lib/active_entity/associations/embeds/collection_association.rb', line 126

def replace(other_array)
  records = other_array.map do |val|
    if val.is_a? reflection.klass
      val
    elsif val.nil?
      next
    elsif val.respond_to?(:to_h)
      build_record(val.to_h)
    end
  rescue => ex
    raise_on_type_mismatch!(val)
    raise ex
  end

  target.replace records
end

#size ⇒ Object

Returns the size of the collection by executing a SELECT COUNT(*) query if the collection hasn’t been loaded, and calling collection.size if it has.

If the collection has been already loaded size and length are equivalent. If not and you are going to need the records anyway length will take one less query. Otherwise size is more efficient.

This method is abstract in the sense that it relies on count_records, which is a method descendants have to provide.



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# File 'lib/active_entity/associations/embeds/collection_association.rb', line 108

def size
  target.size
end

#writer(records) ⇒ Object

Implements the writer method, e.g. foo.items= for Foo.has_many :items



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# File 'lib/active_entity/associations/embeds/collection_association.rb', line 42

def writer(records)
  replace(records)
end