require 'active_record/associations/association_collection'
require 'active_record/associations/has_many_association'
require 'active_record/associations/has_and_belongs_to_many_association'
require 'active_record/deprecated_associations'
module ActiveRecord
module Associations # :nodoc:
def self.append_features(base)
super
base.extend(ClassMethods)
end
# Associations are a set of macro-like class methods for tying objects together through foreign keys. They express relationships like
# "Project has one Project Manager" or "Project belongs to a Portfolio". Each macro adds a number of methods to the class which are
# specialized according to the collection or association symbol and the options hash. It works much the same was as Ruby's own attr*
# methods. Example:
#
# class Project < ActiveRecord::Base
# belongs_to :portfolio
# has_one :project_manager
# has_many :milestones
# has_and_belongs_to_many :categories
# end
#
# The project class now has the following methods (and more) to ease the traversal and manipulation of its relationships:
# * <tt>Project#portfolio, Project#portfolio=(portfolio), Project#portfolio.nil?, Project#portfolio?(portfolio)</tt>
# * <tt>Project#project_manager, Project#project_manager=(project_manager), Project#project_manager.nil?,</tt>
# <tt>Project#project_manager?(project_manager), Project#build_project_manager, Project#create_project_manager</tt>
# * <tt>Project#milestones.empty?, Project#milestones.size, Project#milestones, Project#milestones<<(milestone),</tt>
# <tt>Project#milestones.delete(milestone), Project#milestones.find(milestone_id), Project#milestones.find_all(conditions),</tt>
# <tt>Project#milestones.build, Project#milestones.create</tt>
# * <tt>Project#categories.empty?, Project#categories.size, Project#categories, Project#categories<<(category1),</tt>
# <tt>Project#categories.delete(category1)</tt>
#
# == Example
#
# link:../examples/associations.png
#
# == Is it belongs_to or has_one?
#
# Both express a 1-1 relationship, the difference is mostly where to place the foreign key, which goes on the table for the class
# saying belongs_to. Example:
#
# class Post < ActiveRecord::Base
# has_one :author
# end
#
# class Author < ActiveRecord::Base
# belongs_to :post
# end
#
# The tables for these classes could look something like:
#
# CREATE TABLE posts (
# id int(11) NOT NULL auto_increment,
# title varchar default NULL,
# PRIMARY KEY (id)
# )
#
# CREATE TABLE authors (
# id int(11) NOT NULL auto_increment,
# post_id int(11) default NULL,
# name varchar default NULL,
# PRIMARY KEY (id)
# )
#
# == Caching
#
# All of the methods are built on a simple caching principle that will keep the result of the last query around unless specifically
# instructed not to. The cache is even shared across methods to make it even cheaper to use the macro-added methods without
# worrying too much about performance at the first go. Example:
#
# project.milestones # fetches milestones from the database
# project.milestones.size # uses the milestone cache
# project.milestones.empty? # uses the milestone cache
# project.milestones(true).size # fetches milestones from the database
# project.milestones # uses the milestone cache
#
# == Modules
#
# By default, associations will look for objects within the current module scope. Consider:
#
# module MyApplication
# module Business
# class Firm < ActiveRecord::Base
# has_many :clients
# end
#
# class Company < ActiveRecord::Base; end
# end
# end
#
# When Firm#clients is called, it'll in turn call <tt>MyApplication::Business::Company.find(firm.id)</tt>. If you want to associate
# with a class in another module scope this can be done by specifying the complete class name, such as:
#
# module MyApplication
# module Business
# class Firm < ActiveRecord::Base; end
# end
#
# module Billing
# class Account < ActiveRecord::Base
# belongs_to :firm, :class_name => "MyApplication::Business::Firm"
# end
# end
# end
#
# == Type safety with ActiveRecord::AssociationTypeMismatch
#
# If you attempt to assign an object to an association that doesn't match the inferred or specified <tt>:class_name</tt>, you'll
# get a ActiveRecord::AssociationTypeMismatch.
#
# == Options
#
# All of the association macros can be specialized through options which makes more complex cases than the simple and guessable ones
# possible.
module ClassMethods
# Adds the following methods for retrival and query of collections of associated objects.
# +collection+ is replaced with the symbol passed as the first argument, so
# <tt>has_many :clients</tt> would add among others <tt>has_clients?</tt>.
# * <tt>collection(force_reload = false)</tt> - returns an array of all the associated objects.
# An empty array is returned if none are found.
# * <tt>collection<<(object, ...)</tt> - adds one or more objects to the collection by setting their foreign keys to the collection's primary key.
# * <tt>collection.delete(object, ...)</tt> - removes one or more objects from the collection by setting their foreign keys to NULL. This does not destroy the objects.
# * <tt>collection.clear</tt> - removes every object from the collection. This does not destroy the objects.
# * <tt>collection.empty?</tt> - returns true if there are no associated objects.
# * <tt>collection.size</tt> - returns the number of associated objects.
# * <tt>collection.find(id)</tt> - finds an associated object responding to the +id+ and that
# meets the condition that it has to be associated with this object.
# * <tt>collection.find_all(conditions = nil, orderings = nil, limit = nil, joins = nil)</tt> - finds all associated objects responding
# criterias mentioned (like in the standard find_all) and that meets the condition that it has to be associated with this object.
# * <tt>collection.build(attributes = {})</tt> - returns a new object of the collection type that has been instantiated
# with +attributes+ and linked to this object through a foreign key but has not yet been saved.
# * <tt>collection.create(attributes = {})</tt> - returns a new object of the collection type that has been instantiated
# with +attributes+ and linked to this object through a foreign key and that has already been saved (if it passed the validation).
#
# Example: A Firm class declares <tt>has_many :clients</tt>, which will add:
# * <tt>Firm#clients</tt> (similar to <tt>Clients.find_all "firm_id = #{id}"</tt>)
# * <tt>Firm#clients<<</tt>
# * <tt>Firm#clients.delete</tt>
# * <tt>Firm#clients.clear</tt>
# * <tt>Firm#clients.empty?</tt> (similar to <tt>firm.clients.size == 0</tt>)
# * <tt>Firm#clients.size</tt> (similar to <tt>Client.count "firm_id = #{id}"</tt>)
# * <tt>Firm#clients.find</tt> (similar to <tt>Client.find_on_conditions(id, "firm_id = #{id}")</tt>)
# * <tt>Firm#clients.find_all</tt> (similar to <tt>Client.find_all "firm_id = #{id}"</tt>)
# * <tt>Firm#clients.build</tt> (similar to <tt>Client.new("firm_id" => id)</tt>)
# * <tt>Firm#clients.create</tt> (similar to <tt>c = Client.new("client_id" => id); c.save; c</tt>)
# The declaration can also include an options hash to specialize the behavior of the association.
#
# Options are:
# * <tt>:class_name</tt> - specify the class name of the association. Use it only if that name can't be infered
# from the association name. So <tt>has_many :products</tt> will by default be linked to the +Product+ class, but
# if the real class name is +SpecialProduct+, you'll have to specify it with this option.
# * <tt>:conditions</tt> - specify the conditions that the associated objects must meet in order to be included as a "WHERE"
# sql fragment, such as "price > 5 AND name LIKE 'B%'".
# * <tt>:order</tt> - specify the order in which the associated objects are returned as a "ORDER BY" sql fragment,
# such as "last_name, first_name DESC"
# * <tt>:foreign_key</tt> - specify the foreign key used for the association. By default this is guessed to be the name
# of this class in lower-case and "_id" suffixed. So a +Person+ class that makes a has_many association will use "person_id"
# as the default foreign_key.
# * <tt>:dependent</tt> - if set to true all the associated object are destroyed alongside this object.
# May not be set if :exclusively_dependent is also set.
# * <tt>:exclusively_dependent</tt> - if set to true all the associated object are deleted in one SQL statement without having their
# before_destroy callback run. This should only be used on associations that depend solely on this class and don't need to do any
# clean-up in before_destroy. The upside is that it's much faster, especially if there's a counter_cache involved.
# May not be set if :dependent is also set.
# * <tt>:finder_sql</tt> - specify a complete SQL statement to fetch the association. This is a good way to go for complex
# associations that depends on multiple tables. Note: When this option is used, +find_in_collection+ is _not_ added.
# * <tt>:counter_sql</tt> - specify a complete SQL statement to fetch the size of the association. If +:finder_sql+ is
# specified but +:counter_sql+, +:counter_sql+ will be generated by replacing SELECT ... FROM with SELECT COUNT(*) FROM.
#
# Option examples:
# has_many :comments, :order => "posted_on"
# has_many :people, :class_name => "Person", :conditions => "deleted = 0", :order => "name"
# has_many :tracks, :order => "position", :dependent => true
# has_many :subscribers, :class_name => "Person", :finder_sql =>
# 'SELECT DISTINCT people.* ' +
# 'FROM people p, post_subscriptions ps ' +
# 'WHERE ps.post_id = #{id} AND ps.person_id = p.id ' +
# 'ORDER BY p.first_name'
def has_many(association_id, options = {})
validate_options([ :foreign_key, :class_name, :exclusively_dependent, :dependent, :conditions, :order, :finder_sql, :counter_sql ], options.keys)
association_name, association_class_name, association_class_primary_key_name =
associate_identification(association_id, options[:class_name], options[:foreign_key])
require_association_class(association_class_name)
if options[:dependent] and options[:exclusively_dependent]
raise ArgumentError, ':dependent and :exclusively_dependent are mutually exclusive options. You may specify one or the other.' # ' ruby-mode
elsif options[:dependent]
module_eval "before_destroy '#{association_name}.each { |o| o.destroy }'"
elsif options[:exclusively_dependent]
module_eval "before_destroy { |record| #{association_class_name}.delete_all(%(#{association_class_primary_key_name} = \#{record.quoted_id})) }"
end
define_method(association_name) do |*params|
force_reload = params.first unless params.empty?
association = instance_variable_get("@#{association_name}")
if association.nil?
association = HasManyAssociation.new(self,
association_name, association_class_name,
association_class_primary_key_name, options)
instance_variable_set("@#{association_name}", association)
end
association.reload if force_reload
association
end
# deprecated api
deprecated_collection_count_method(association_name)
deprecated_add_association_relation(association_name)
deprecated_remove_association_relation(association_name)
deprecated_has_collection_method(association_name)
deprecated_find_in_collection_method(association_name)
deprecated_find_all_in_collection_method(association_name)
deprecated_create_method(association_name)
deprecated_build_method(association_name)
end
# Adds the following methods for retrival and query of a single associated object.
# +association+ is replaced with the symbol passed as the first argument, so
# <tt>has_one :manager</tt> would add among others <tt>has_manager?</tt>.
# * <tt>association(force_reload = false)</tt> - returns the associated object. Nil is returned if none is found.
# * <tt>association=(associate)</tt> - assigns the associate object, extracts the primary key, sets it as the foreign key,
# and saves the associate object.
# * <tt>association?(object, force_reload = false)</tt> - returns true if the +object+ is of the same type and has the
# same id as the associated object.
# * <tt>association.nil?</tt> - returns true if there is no associated object.
# * <tt>build_association(attributes = {})</tt> - returns a new object of the associated type that has been instantiated
# with +attributes+ and linked to this object through a foreign key but has not yet been saved.
# * <tt>create_association(attributes = {})</tt> - returns a new object of the associated type that has been instantiated
# with +attributes+ and linked to this object through a foreign key and that has already been saved (if it passed the validation).
#
# Example: An Account class declares <tt>has_one :beneficiary</tt>, which will add:
# * <tt>Account#beneficiary</tt> (similar to <tt>Beneficiary.find_first "account_id = #{id}"</tt>)
# * <tt>Account#beneficiary=(beneficiary)</tt> (similar to <tt>beneficiary.account_id = account.id; beneficiary.save</tt>)
# * <tt>Account#beneficiary?</tt> (similar to <tt>account.beneficiary == some_beneficiary</tt>)
# * <tt>Account#beneficiary.nil?</tt>
# * <tt>Account#build_beneficiary</tt> (similar to <tt>Beneficiary.new("account_id" => id)</tt>)
# * <tt>Account#create_beneficiary</tt> (similar to <tt>b = Beneficiary.new("account_id" => id); b.save; b</tt>)
# The declaration can also include an options hash to specialize the behavior of the association.
#
# Options are:
# * <tt>:class_name</tt> - specify the class name of the association. Use it only if that name can't be infered
# from the association name. So <tt>has_one :manager</tt> will by default be linked to the +Manager+ class, but
# if the real class name is +Person+, you'll have to specify it with this option.
# * <tt>:conditions</tt> - specify the conditions that the associated object must meet in order to be included as a "WHERE"
# sql fragment, such as "rank = 5".
# * <tt>:order</tt> - specify the order from which the associated object will be picked at the top. Specified as
# an "ORDER BY" sql fragment, such as "last_name, first_name DESC"
# * <tt>:dependent</tt> - if set to true the associated object is destroyed alongside this object
# * <tt>:foreign_key</tt> - specify the foreign key used for the association. By default this is guessed to be the name
# of this class in lower-case and "_id" suffixed. So a +Person+ class that makes a has_one association will use "person_id"
# as the default foreign_key.
#
# Option examples:
# has_one :credit_card, :dependent => true
# has_one :last_comment, :class_name => "Comment", :order => "posted_on"
# has_one :project_manager, :class_name => "Person", :conditions => "role = 'project_manager'"
def has_one(association_id, options = {})
options.merge!({ :remote => true })
belongs_to(association_id, options)
association_name, association_class_name, class_primary_key_name =
associate_identification(association_id, options[:class_name], options[:foreign_key], false)
require_association_class(association_class_name)
has_one_writer_method(association_name, association_class_name, class_primary_key_name)
build_method("build_", association_name, association_class_name, class_primary_key_name)
create_method("create_", association_name, association_class_name, class_primary_key_name)
module_eval "before_destroy '#{association_name}.destroy if has_#{association_name}?'" if options[:dependent]
end
# Adds the following methods for retrival and query for a single associated object that this object holds an id to.
# +association+ is replaced with the symbol passed as the first argument, so
# <tt>belongs_to :author</tt> would add among others <tt>has_author?</tt>.
# * <tt>association(force_reload = false)</tt> - returns the associated object. Nil is returned if none is found.
# * <tt>association=(associate)</tt> - assigns the associate object, extracts the primary key, and sets it as the foreign key.
# * <tt>association?(object, force_reload = false)</tt> - returns true if the +object+ is of the same type and has the
# same id as the associated object.
# * <tt>association.nil?</tt> - returns true if there is no associated object.
#
# Example: An Post class declares <tt>has_one :author</tt>, which will add:
# * <tt>Post#author</tt> (similar to <tt>Author.find(author_id)</tt>)
# * <tt>Post#author=(author)</tt> (similar to <tt>post.author_id = author.id</tt>)
# * <tt>Post#author?</tt> (similar to <tt>post.author == some_author</tt>)
# * <tt>Post#author.nil?</tt>
# The declaration can also include an options hash to specialize the behavior of the association.
#
# Options are:
# * <tt>:class_name</tt> - specify the class name of the association. Use it only if that name can't be infered
# from the association name. So <tt>has_one :author</tt> will by default be linked to the +Author+ class, but
# if the real class name is +Person+, you'll have to specify it with this option.
# * <tt>:conditions</tt> - specify the conditions that the associated object must meet in order to be included as a "WHERE"
# sql fragment, such as "authorized = 1".
# * <tt>:order</tt> - specify the order from which the associated object will be picked at the top. Specified as
# an "ORDER BY" sql fragment, such as "last_name, first_name DESC"
# * <tt>:foreign_key</tt> - specify the foreign key used for the association. By default this is guessed to be the name
# of the associated class in lower-case and "_id" suffixed. So a +Person+ class that makes a belongs_to association to a
# +Boss+ class will use "boss_id" as the default foreign_key.
# * <tt>:counter_cache</tt> - caches the number of belonging objects on the associate class through use of increment_counter
# and decrement_counter. The counter cache is incremented when an object of this class is created and decremented when it's
# destroyed. This requires that a column named "#{table_name}_count" (such as comments_count for a belonging Comment class)
# is used on the associate class (such as a Post class).
#
# Option examples:
# belongs_to :firm, :foreign_key => "client_of"
# belongs_to :author, :class_name => "Person", :foreign_key => "author_id"
# belongs_to :valid_coupon, :class_name => "Coupon", :foreign_key => "coupon_id",
# :conditions => 'discounts > #{payments_count}'
def belongs_to(association_id, options = {})
validate_options([ :class_name, :foreign_key, :remote, :conditions, :order, :dependent, :counter_cache ], options.keys)
association_name, association_class_name, class_primary_key_name =
associate_identification(association_id, options[:class_name], options[:foreign_key], false)
require_association_class(association_class_name)
association_class_primary_key_name = options[:foreign_key] || Inflector.underscore(Inflector.demodulize(association_class_name)) + "_id"
if options[:remote]
association_finder = <<-"end_eval"
#{association_class_name}.find_first(
"#{class_primary_key_name} = \#{quoted_id}#{options[:conditions] ? " AND " + options[:conditions] : ""}",
#{options[:order] ? "\"" + options[:order] + "\"" : "nil" }
)
end_eval
else
association_finder = options[:conditions] ?
"#{association_class_name}.find_on_conditions(#{association_class_primary_key_name}, \"#{options[:conditions]}\")" :
"#{association_class_name}.find(#{association_class_primary_key_name})"
end
has_association_method(association_name)
association_reader_method(association_name, association_finder)
belongs_to_writer_method(association_name, association_class_name, association_class_primary_key_name)
association_comparison_method(association_name, association_class_name)
if options[:counter_cache]
module_eval(
"after_create '#{association_class_name}.increment_counter(\"#{Inflector.pluralize(self.to_s.downcase). + "_count"}\", #{association_class_primary_key_name})" +
" if has_#{association_name}?'"
)
module_eval(
"before_destroy '#{association_class_name}.decrement_counter(\"#{Inflector.pluralize(self.to_s.downcase) + "_count"}\", #{association_class_primary_key_name})" +
" if has_#{association_name}?'"
)
end
end
# Associates two classes via an intermediate join table. Unless the join table is explicitly specified as
# an option, it is guessed using the lexical order of the class names. So a join between Developer and Project
# will give the default join table name of "developers_projects" because "D" outranks "P".
#
# Any additional fields added to the join table will be placed as attributes when pulling records out through
# has_and_belongs_to_many associations. This is helpful when have information about the association itself
# that you want available on retrival.
#
# Adds the following methods for retrival and query.
# +collection+ is replaced with the symbol passed as the first argument, so
# <tt>has_and_belongs_to_many :categories</tt> would add among others +add_categories+.
# * <tt>collection(force_reload = false)</tt> - returns an array of all the associated objects.
# An empty array is returned if none is found.
# * <tt>collection<<(object, ...)</tt> - adds one or more objects to the collection by creating associations in the join table
# (collection.push and collection.concat are aliases to this method).
# * <tt>collection.push_with_attributes(object, join_attributes)</tt> - adds one to the collection by creating an association in the join table that
# also holds the attributes from <tt>join_attributes</tt> (should be a hash with the column names as keys). This can be used to have additional
# attributes on the join, which will be injected into the associated objects when they are retrieved through the collection.
# (collection.concat_with_attributes is an alias to this method).
# * <tt>collection.delete(object, ...)</tt> - removes one or more objects from the collection by removing their associations from the join table.
# This does not destroy the objects.
# * <tt>collection.clear</tt> - removes every object from the collection. This does not destroy the objects.
# * <tt>collection.empty?</tt> - returns true if there are no associated objects.
# * <tt>collection.size</tt> - returns the number of associated objects.
#
# Example: An Developer class declares <tt>has_and_belongs_to_many :projects</tt>, which will add:
# * <tt>Developer#projects</tt>
# * <tt>Developer#projects<<</tt>
# * <tt>Developer#projects.delete</tt>
# * <tt>Developer#projects.clear</tt>
# * <tt>Developer#projects.empty?</tt>
# * <tt>Developer#projects.size</tt>
# * <tt>Developer#projects.find(id)</tt>
# The declaration may include an options hash to specialize the behavior of the association.
#
# Options are:
# * <tt>:class_name</tt> - specify the class name of the association. Use it only if that name can't be infered
# from the association name. So <tt>has_and_belongs_to_many :projects</tt> will by default be linked to the
# +Project+ class, but if the real class name is +SuperProject+, you'll have to specify it with this option.
# * <tt>:join_table</tt> - specify the name of the join table if the default based on lexical order isn't what you want.
# WARNING: If you're overwriting the table name of either class, the table_name method MUST be declared underneath any
# has_and_belongs_to_many declaration in order to work.
# * <tt>:foreign_key</tt> - specify the foreign key used for the association. By default this is guessed to be the name
# of this class in lower-case and "_id" suffixed. So a +Person+ class that makes a has_and_belongs_to_many association
# will use "person_id" as the default foreign_key.
# * <tt>:association_foreign_key</tt> - specify the association foreign key used for the association. By default this is
# guessed to be the name of the associated class in lower-case and "_id" suffixed. So the associated class is +Project+
# that makes a has_and_belongs_to_many association will use "project_id" as the default association foreign_key.
# * <tt>:conditions</tt> - specify the conditions that the associated object must meet in order to be included as a "WHERE"
# sql fragment, such as "authorized = 1".
# * <tt>:order</tt> - specify the order in which the associated objects are returned as a "ORDER BY" sql fragment, such as "last_name, first_name DESC"
# * <tt>:uniq</tt> - if set to true, duplicate associated objects will be ignored by accessors and query methods
# * <tt>:finder_sql</tt> - overwrite the default generated SQL used to fetch the association with a manual one
# * <tt>:delete_sql</tt> - overwrite the default generated SQL used to remove links between the associated
# classes with a manual one
# * <tt>:insert_sql</tt> - overwrite the default generated SQL used to add links between the associated classes
# with a manual one
#
# Option examples:
# has_and_belongs_to_many :projects
# has_and_belongs_to_many :nations, :class_name => "Country"
# has_and_belongs_to_many :categories, :join_table => "prods_cats"
def has_and_belongs_to_many(association_id, options = {})
validate_options([ :class_name, :table_name, :foreign_key, :association_foreign_key, :conditions,
:join_table, :finder_sql, :delete_sql, :insert_sql, :order, :uniq ], options.keys)
association_name, association_class_name, association_class_primary_key_name =
associate_identification(association_id, options[:class_name], options[:foreign_key])
require_association_class(association_class_name)
join_table = options[:join_table] ||
join_table_name(undecorated_table_name(self.to_s), undecorated_table_name(association_class_name))
define_method(association_name) do |*params|
force_reload = params.first unless params.empty?
association = instance_variable_get("@#{association_name}")
if association.nil?
association = HasAndBelongsToManyAssociation.new(self,
association_name, association_class_name,
association_class_primary_key_name, join_table, options)
instance_variable_set("@#{association_name}", association)
end
association.reload if force_reload
association
end
before_destroy_sql = "DELETE FROM #{join_table} WHERE #{association_class_primary_key_name} = \\\#{self.quoted_id}"
module_eval(%{before_destroy "self.connection.delete(%{#{before_destroy_sql}})"}) # "
# deprecated api
deprecated_collection_count_method(association_name)
deprecated_add_association_relation(association_name)
deprecated_remove_association_relation(association_name)
deprecated_has_collection_method(association_name)
end
private
# Raises an exception if an invalid option has been specified to prevent misspellings from slipping through
def validate_options(valid_option_keys, supplied_option_keys)
unknown_option_keys = supplied_option_keys - valid_option_keys
raise(ActiveRecord::ActiveRecordError, "Unknown options: #{unknown_option_keys}") unless unknown_option_keys.empty?
end
def join_table_name(first_table_name, second_table_name)
if first_table_name < second_table_name
join_table = "#{first_table_name}_#{second_table_name}"
else
join_table = "#{second_table_name}_#{first_table_name}"
end
table_name_prefix + join_table + table_name_suffix
end
def associate_identification(association_id, association_class_name, foreign_key, plural = true)
if association_class_name !~ /::/
association_class_name = type_name_with_module(
association_class_name ||
Inflector.camelize(plural ? Inflector.singularize(association_id.id2name) : association_id.id2name)
)
end
primary_key_name = foreign_key || Inflector.underscore(Inflector.demodulize(name)) + "_id"
return association_id.id2name, association_class_name, primary_key_name
end
def association_comparison_method(association_name, association_class_name)
module_eval <<-"end_eval", __FILE__, __LINE__
def #{association_name}?(comparison_object, force_reload = false)
if comparison_object.kind_of?(#{association_class_name})
#{association_name}(force_reload) == comparison_object
else
raise "Comparison object is a #{association_class_name}, should have been \#{comparison_object.class.name}"
end
end
end_eval
end
def association_reader_method(association_name, association_finder)
module_eval <<-"end_eval", __FILE__, __LINE__
def #{association_name}(force_reload = false)
if @#{association_name}.nil? || force_reload
begin
@#{association_name} = #{association_finder}
rescue ActiveRecord::StatementInvalid, ActiveRecord::RecordNotFound
nil
end
end
return @#{association_name}
end
end_eval
end
def has_one_writer_method(association_name, association_class_name, class_primary_key_name)
module_eval <<-"end_eval", __FILE__, __LINE__
def #{association_name}=(association)
if association.nil?
@#{association_name}.#{class_primary_key_name} = nil
@#{association_name}.save(false)
@#{association_name} = nil
else
raise ActiveRecord::AssociationTypeMismatch unless #{association_class_name} === association
association.#{class_primary_key_name} = id
association.save(false)
@#{association_name} = association
end
end
end_eval
end
def belongs_to_writer_method(association_name, association_class_name, association_class_primary_key_name)
module_eval <<-"end_eval", __FILE__, __LINE__
def #{association_name}=(association)
if association.nil?
@#{association_name} = self.#{association_class_primary_key_name} = nil
else
raise ActiveRecord::AssociationTypeMismatch unless #{association_class_name} === association
@#{association_name} = association
self.#{association_class_primary_key_name} = association.id
end
end
end_eval
end
def has_association_method(association_name)
module_eval <<-"end_eval", __FILE__, __LINE__
def has_#{association_name}?(force_reload = false)
!#{association_name}(force_reload).nil?
end
end_eval
end
def build_method(method_prefix, collection_name, collection_class_name, class_primary_key_name)
module_eval <<-"end_eval", __FILE__, __LINE__
def #{method_prefix + collection_name}(attributes = {})
association = #{collection_class_name}.new
association.attributes = attributes.merge({ "#{class_primary_key_name}" => id})
association
end
end_eval
end
def create_method(method_prefix, collection_name, collection_class_name, class_primary_key_name)
module_eval <<-"end_eval", __FILE__, __LINE__
def #{method_prefix + collection_name}(attributes = nil)
#{collection_class_name}.create((attributes || {}).merge({ "#{class_primary_key_name}" => id}))
end
end_eval
end
def require_association_class(class_name)
begin
require_association(Inflector.underscore(class_name))
rescue LoadError
# Failed to load the associated class -- let's hope the developer is doing the requiring himself.
end
end
end
end
end
