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Diffstat (limited to 'activerecord/lib/active_record/associations.rb')
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diff --git a/activerecord/lib/active_record/associations.rb b/activerecord/lib/active_record/associations.rb new file mode 100755 index 0000000000..6285a59882 --- /dev/null +++ b/activerecord/lib/active_record/associations.rb @@ -0,0 +1,576 @@ +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. + # + # 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 ], 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.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} = '\#{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.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(Inflector.underscore(class_name)) + rescue LoadError + if logger + logger.info "#{self.to_s} failed to require #{class_name}" + else + STDERR << "#{self.to_s} failed to require #{class_name}\n" + end + end + end + end + end +end |