* Mark Ma <[EMAIL PROTECTED]> [2008-10-06 20:59:58 +0200]: > > can anyone tell me how before filter can call the private method audit > which from the parent class ? > because the bank controller has a private method called audit, this one > should not be inheritance by VaultController, so how the before_filter > use the private method audit ? > > if the child class can use the parent class private method . does it > break encapsulation ? does the private has any sense here .because you > can use it from ur child class , why just make it public ?
Ruby's private/public concept is different from those in other language like java. Make a method private means you can't invoke it unless the receiver is 'self'. So you can use parent's private methods in its children, but you can't use Foo's private methods in a class who is not child of Foo. Jan > > below is the example from rail api. > > > > Controller inheritance hierarchies share filters downwards, but > subclasses can also add or skip filters without affecting the > superclass. For example: > > class BankController < ActionController::Base > before_filter :audit > > private > def audit > # record the action and parameters in an audit log > end > end > > class VaultController < BankController > before_filter :verify_credentials > > private > def verify_credentials > # make sure the user is allowed into the vault > end > end > > Now any actions performed on the BankController will have the audit > method called before. On the VaultController, first the audit method is > called, then the verify_credentials method. If the audit method renders > or redirects, then verify_credentials and the intended action are never > called. > -- > Posted via http://www.ruby-forum.com/. > > --~--~---------~--~----~------------~-------~--~----~ > You received this message because you are subscribed to the Google Groups > "Ruby on Rails: Talk" group. > To post to this group, send email to rubyonrails-talk@googlegroups.com > To unsubscribe from this group, send email to [EMAIL PROTECTED] > For more options, visit this group at > http://groups.google.com/group/rubyonrails-talk?hl=en > -~----------~----~----~----~------~----~------~--~--- -- jan=callcc{|jan|jan};jan.call(jan)
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