Self and Protected Methods question/confusion

Hi,

I’m still trying to learn the in’s and out’s of Ruby and Rails. I’ve
been testing my code a million different ways and have read a number of
books and web sites, but something is still not clicking for me. I want
to be able to call the protected methods and I have read both David
Black’s and Prag Programmers books about how self can be tricky. But I
still don’t know how to make it work. I want to call method_a and have
it then process both protected methods.

Is it possible to call my method_a directly (as shown in my script code)
without having to do this:

k = Klass.new
k.method_a


I’ve got this right now.

This is called from a script.
k = Klass.method_a(:variable = v)

My model:
class Klass

def self.method_a(params = {})
a = Model.find(:first, :conditions => [“variable = ?”, variable])
a.do_something
a.do_more
return a
end

protected

def do_something
puts “inside do_something”
end

def do_more
puts “inside do_more”
end

end

Thanks for helping a Ruby N…

Greg D. wrote:

Here’s an example:

#!/usr/bin/env ruby

class Foo
private
def hidden
puts “I am hidden”
end
end

f = Foo.new

begin
f.hidden
rescue
puts “Can’t run hidden: #{ $! }”
end

f.send( :hidden )

./private.rb

Can’t run hidden: private method `hidden’ called for #Foo:0xb7c2f92c
I am hidden

Thank you for your example. I was able to test my code and call my
methods using object.send (:method)

My follow-up question to this is now, is this the best way to handle the
protected methods using the code sample that I have above? Or do I have
a design flaw in the code? Should I explicitly create and call
object.New and the method instead of creating the object like I am
doing?

Thanks for your help.

On Mon, Oct 26, 2009 at 5:26 PM, Cs Webgrl
[email protected] wrote:

I’m still trying to learn the in’s and out’s of Ruby and Rails. I’ve
been testing my code a million different ways and have read a number of
books and web sites, but something is still not clicking for me. I want
to be able to call the protected methods

Ruby’s object system is a message passing system. If you have an
object foo, and you do:

foo.some_method

foo doesn’t perform a method call on itself. foo just looks for
somewhere to send the “some_method” message, somewhere that returns
true for respond_to?

foo.respond_to?(:some_message)

In knowing how this works, you can send the message yourself, ignoring
the private or protected nature of the receiver along the way.

Here’s an example:

#!/usr/bin/env ruby

class Foo
private
def hidden
puts “I am hidden”
end
end

f = Foo.new

begin
f.hidden
rescue
puts “Can’t run hidden: #{ $! }”
end

f.send( :hidden )

./private.rb

Can’t run hidden: private method `hidden’ called for #Foo:0xb7c2f92c
I am hidden


Greg D.
http://destiney.com/

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