diff options
Diffstat (limited to 'activerecord/lib/active_record/callbacks.rb')
| -rwxr-xr-x | activerecord/lib/active_record/callbacks.rb | 100 |
1 files changed, 50 insertions, 50 deletions
diff --git a/activerecord/lib/active_record/callbacks.rb b/activerecord/lib/active_record/callbacks.rb index 7a19dcb746..83c54680b5 100755 --- a/activerecord/lib/active_record/callbacks.rb +++ b/activerecord/lib/active_record/callbacks.rb @@ -1,25 +1,25 @@ require 'observer' module ActiveRecord - # Callbacks are hooks into the lifecycle of an Active Record object that allows you to trigger logic + # Callbacks are hooks into the lifecycle of an Active Record object that allow you to trigger logic # before or after an alteration of the object state. This can be used to make sure that associated and - # dependent objects are deleted when destroy is called (by overwriting before_destroy) or to massage attributes - # before they're validated (by overwriting before_validation). As an example of the callbacks initiated, consider - # the Base#save call: - # - # * (-) save - # * (-) valid? - # * (1) before_validation - # * (2) before_validation_on_create - # * (-) validate - # * (-) validate_on_create - # * (3) after_validation - # * (4) after_validation_on_create - # * (5) before_save - # * (6) before_create - # * (-) create - # * (7) after_create - # * (8) after_save + # dependent objects are deleted when destroy is called (by overwriting +before_destroy+) or to massage attributes + # before they're validated (by overwriting +before_validation+). As an example of the callbacks initiated, consider + # the <tt>Base#save</tt> call: + # + # * (-) <tt>save</tt> + # * (-) <tt>valid</tt> + # * (1) <tt>before_validation</tt> + # * (2) <tt>before_validation_on_create</tt> + # * (-) <tt>validate</tt> + # * (-) <tt>validate_on_create</tt> + # * (3) <tt>after_validation</tt> + # * (4) <tt>after_validation_on_create</tt> + # * (5) <tt>before_save</tt> + # * (6) <tt>before_create</tt> + # * (-) <tt>create</tt> + # * (7) <tt>after_create</tt> + # * (8) <tt>after_save</tt> # # That's a total of eight callbacks, which gives you immense power to react and prepare for each state in the # Active Record lifecycle. @@ -62,8 +62,8 @@ module ActiveRecord # before_destroy :destroy_readers # end # - # Now, when Topic#destroy is run only +destroy_author+ is called. When Reply#destroy is run both +destroy_author+ and - # +destroy_readers+ is called. Contrast this to the situation where we've implemented the save behavior through overwriteable + # Now, when <tt>Topic#destroy</tt> is run only +destroy_author+ is called. When <tt>Reply#destroy</tt> is run, both +destroy_author+ and + # +destroy_readers+ are called. Contrast this to the situation where we've implemented the save behavior through overwriteable # methods: # # class Topic < ActiveRecord::Base @@ -74,9 +74,9 @@ module ActiveRecord # def before_destroy() destroy_readers end # end # - # In that case, Reply#destroy would only run +destroy_readers+ and _not_ +destroy_author+. So use the callback macros when - # you want to ensure that a certain callback is called for the entire hierarchy and the regular overwriteable methods when you - # want to leave it up to each descendent to decide whether they want to call +super+ and trigger the inherited callbacks. + # In that case, <tt>Reply#destroy</tt> would only run +destroy_readers+ and _not_ +destroy_author+. So, use the callback macros when + # you want to ensure that a certain callback is called for the entire hierarchy, and use the regular overwriteable methods + # when you want to leave it up to each descendent to decide whether they want to call +super+ and trigger the inherited callbacks. # # *IMPORTANT:* In order for inheritance to work for the callback queues, you must specify the callbacks before specifying the # associations. Otherwise, you might trigger the loading of a child before the parent has registered the callbacks and they won't @@ -143,7 +143,7 @@ module ActiveRecord # before_destroy 'self.class.delete_all "parent_id = #{id}"' # end # - # Notice that single plings (') are used so the #{id} part isn't evaluated until the callback is triggered. Also note that these + # Notice that single plings (') are used so the <tt>#{id}</tt> part isn't evaluated until the callback is triggered. Also note that these # inline callbacks can be stacked just like the regular ones: # # class Topic < ActiveRecord::Base @@ -151,23 +151,23 @@ module ActiveRecord # 'puts "Evaluated after parents are destroyed"' # end # - # == The after_find and after_initialize exceptions + # == The +after_find+ and +after_initialize+ exceptions # - # Because after_find and after_initialize are called for each object found and instantiated by a finder, such as Base.find(:all), we've had - # to implement a simple performance constraint (50% more speed on a simple test case). Unlike all the other callbacks, after_find and - # after_initialize will only be run if an explicit implementation is defined (<tt>def after_find</tt>). In that case, all of the + # Because +after_find+ and +after_initialize+ are called for each object found and instantiated by a finder, such as <tt>Base.find(:all)</tt>, we've had + # to implement a simple performance constraint (50% more speed on a simple test case). Unlike all the other callbacks, +after_find+ and + # +after_initialize+ will only be run if an explicit implementation is defined (<tt>def after_find</tt>). In that case, all of the # callback types will be called. # - # == before_validation* returning statements + # == <tt>before_validation*</tt> returning statements # - # If the returning value of a before_validation callback can be evaluated to false, the process will be aborted and Base#save will return false. - # If Base#save! is called it will raise a RecordNotSave error. + # If the returning value of a +before_validation+ callback can be evaluated to +false+, the process will be aborted and <tt>Base#save</tt> will return +false+. + # If <tt>Base#save!</tt> is called it will raise a +RecordNotSave+ exception. # Nothing will be appended to the errors object. # # == Cancelling callbacks # - # If a before_* callback returns false, all the later callbacks and the associated action are cancelled. If an after_* callback returns - # false, all the later callbacks are cancelled. Callbacks are generally run in the order they are defined, with the exception of callbacks + # If a <tt>before_*</tt> callback returns +false+, all the later callbacks and the associated action are cancelled. If an <tt>after_*</tt> callback returns + # +false+, all the later callbacks are cancelled. Callbacks are generally run in the order they are defined, with the exception of callbacks # defined as methods on the model, which are called last. module Callbacks CALLBACKS = %w( @@ -215,10 +215,10 @@ module ActiveRecord end end - # Is called when the object was instantiated by one of the finders, like Base.find. + # Is called when the object was instantiated by one of the finders, like <tt>Base.find</tt>. #def after_find() end - # Is called after the object has been instantiated by a call to Base.new. + # Is called after the object has been instantiated by a call to <tt>Base.new</tt>. #def after_initialize() end def initialize_with_callbacks(attributes = nil) #:nodoc: @@ -229,10 +229,10 @@ module ActiveRecord end private :initialize_with_callbacks - # Is called _before_ Base.save (regardless of whether it's a create or update save). + # Is called _before_ <tt>Base.save</tt> (regardless of whether it's a +create+ or +update+ save). def before_save() end - # Is called _after_ Base.save (regardless of whether it's a create or update save). + # Is called _after_ <tt>Base.save</tt> (regardless of whether it's a +create+ or +update+ save). # # class Contact < ActiveRecord::Base # after_save { logger.info( 'New contact saved!' ) } @@ -246,10 +246,10 @@ module ActiveRecord end private :create_or_update_with_callbacks - # Is called _before_ Base.save on new objects that haven't been saved yet (no record exists). + # Is called _before_ <tt>Base.save</tt> on new objects that haven't been saved yet (no record exists). def before_create() end - # Is called _after_ Base.save on new objects that haven't been saved yet (no record exists). + # Is called _after_ <tt>Base.save</tt> on new objects that haven't been saved yet (no record exists). def after_create() end def create_with_callbacks #:nodoc: return false if callback(:before_create) == false @@ -259,10 +259,10 @@ module ActiveRecord end private :create_with_callbacks - # Is called _before_ Base.save on existing objects that have a record. + # Is called _before_ <tt>Base.save</tt> on existing objects that have a record. def before_update() end - # Is called _after_ Base.save on existing objects that have a record. + # Is called _after_ <tt>Base.save</tt> on existing objects that have a record. def after_update() end def update_with_callbacks #:nodoc: @@ -273,25 +273,25 @@ module ActiveRecord end private :update_with_callbacks - # Is called _before_ Validations.validate (which is part of the Base.save call). + # Is called _before_ <tt>Validations.validate</tt> (which is part of the <tt>Base.save</tt> call). def before_validation() end - # Is called _after_ Validations.validate (which is part of the Base.save call). + # Is called _after_ <tt>Validations.validate</tt> (which is part of the <tt>Base.save</tt> call). def after_validation() end - # Is called _before_ Validations.validate (which is part of the Base.save call) on new objects + # Is called _before_ <tt>Validations.validate</tt> (which is part of the <tt>Base.save</tt> call) on new objects # that haven't been saved yet (no record exists). def before_validation_on_create() end - # Is called _after_ Validations.validate (which is part of the Base.save call) on new objects + # Is called _after_ <tt>Validations.validate</tt> (which is part of the <tt>Base.save</tt> call) on new objects # that haven't been saved yet (no record exists). def after_validation_on_create() end - # Is called _before_ Validations.validate (which is part of the Base.save call) on + # Is called _before_ <tt>Validations.validate</tt> (which is part of the <tt>Base.save</tt> call) on # existing objects that have a record. def before_validation_on_update() end - # Is called _after_ Validations.validate (which is part of the Base.save call) on + # Is called _after_ <tt>Validations.validate</tt> (which is part of the <tt>Base.save</tt> call) on # existing objects that have a record. def after_validation_on_update() end @@ -308,13 +308,13 @@ module ActiveRecord return result end - # Is called _before_ Base.destroy. + # Is called _before_ <tt>Base.destroy</tt>. # # Note: If you need to _destroy_ or _nullify_ associated records first, - # use the _:dependent_ option on your associations. + # use the <tt>:dependent</tt> option on your associations. def before_destroy() end - # Is called _after_ Base.destroy (and all the attributes have been frozen). + # Is called _after_ <tt>Base.destroy</tt> (and all the attributes have been frozen). # # class Contact < ActiveRecord::Base # after_destroy { |record| logger.info( "Contact #{record.id} was destroyed." ) } |