Michael Malone
4/3/2009 2:17:00 AM
denize.paul@gmail.com wrote:
> My intent is to create a class that has access to call a method in an
> instantiation of another class
>
Here be dragons. Have you considered the inheritance idea? If a class
*needs* access to another class's private variables, then the
functionality either belongs in the same class or a child class. Whilst
this is technically legal, it really doesn't bode well. If you
absolutely need Class A to have exactly one instantiation of Class B you
might want to consider the Singleton design pattern for class B. Which
in ruby is _really_ difficult to implement...
include singleton #(or something along those lines) :)
and for B to be a class variable of A (@@b = B.new) which, if they act
like Java statics (and I think they do) the class variable has one
instantiation able to be accessed from any object of the class.
e.g
class B
def initialize()
end
def to_s
"This is class #{class}"
end
end
class A
@@b = B.new()
def intitialize()
puts @@b
end
end
But in truth, you will have to be a little less generic to get a better
answer. If you can give more details of what you're trying to achieve,
then please do, and I'll try and give better help.
Michael
> However my knowledge of Ruby classes (Ok classes in general) is
> somewhat lacking
>
> The example below is a LOT simplified But I need class B to call a
> method within an instantiation of class A's.
>
> one alternative is to seperate the classes and then just do "b=B.new
> (a)" but I think that looks really messy and
> - I have then to check a bunch of stuff about the parameter a
> - I would have a world of more hurt trying to ensure that only one B
> instantiation pointed to each a
>
> Can anyone help? Or tell me that I am doing this all wrong.
>
>
> Paul
>
> -----
>
> class A
> class B
> def initialize()
> puts "b init"
> print_stuff()
> end
> end
>
> def B
> return B
> end
>
> def print_stuff()
> puts "here"
> end
> end
>
> a = A.new()
> b = a.B.new()
>
>
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