[LRUG] Looping through classes

[Srushti Ambekallu]

Also, keep in mind that ObjectSpace is disabled by default on JRuby for performance reasons and they don't recommend enabling it again (although it turns out it works on JRuby locally, so maybe something has changed).

http://ola-bini.blogspot.in/2007/07/objectspace-to-have-or-not-to-have.html
http://kenai.com/projects/jruby/pages/PerformanceTuning#Disabling_ObjectSpace

Thanks,
Srushti
http://c42.in

On 14-Mar-2013, at 11:15 AM, Srushti Ambekallu wrote:

> Collapsing that down you could do:
> 
> 	subclasses = ObjectSpace.each_object do |klass|
> 		if klass.is_a?(Class) && klass.ancestors.include?(Ohm::Model) && klass.instance_methods.include?(:created_at) && klass.instance_methods.include?(:updated_at)
> 			# do the conversion
> 		end
> 	end
> 
> Or you could put that into a method and parameterise "Ohm::Model" so that it can be reused for other classes too.
> 
> Thanks,
> Srushti
> http://c42.in
> 
> On 14-Mar-2013, at 8:10 AM, Ronny Ager-Wick wrote:
> 
>> Thanks, Jon,
>> this is practically what I asked for - a list of all of the objects I need, and a few more. For some reason I got an error on the last line. https://gist.github.com/JonRowe/5158141#comment-797997 Not to worry though, with all the information I got, I'm well on my way to a solution.
>> Ronny.
>> 
>> 
>> On 14/03/13 09:42, Jon Rowe wrote:
>>> You can get the constants of Object or some other top level object, map them into the actual constants (cause Ruby returns them as symbols),and then filter them…
>>> 
>>> Something along the lines of this… https://gist.github.com/JonRowe/5158141
>>> 
>>> Jon Rowe
>>> -----------------------------
>>> mail at jonrowe.co.uk
>>> jonrowe.co.uk
>>> 
>>> On Thursday, 14 March 2013 at 11:38, Ronny Ager-Wick wrote:
>>> 
>>>> I've been trying to find a way to do this, but I may be searching for the
>>>> wrong terms or something because I get nowhere, even with the help of my
>>>> friend Google.
>>>> I want to loop through the defined classes to see which ons of them responds
>>>> to certain methods.
>>>> The classes I'm trying to find are Ohm Models that have a certain attribute
>>>> defined.
>>>> If I had a collection of classes, I'd probably do something like this:
>>>> 
>>>> classes = #get list of all classes
>>>> classes.each { |c|
>>>> # assume it's an Ohm::Model if it responds to :first
>>>> # maybe there's a better way of filtering out only the Ohm models
>>>> if c.respond_to?(:first) && c.first.respond_to?(:updated_at)
>>>> # convert the timestamp of all records in this model.
>>>> end
>>>> end
>>>> 
>>>> The end objective is to convert the timestamp from the old way they used to
>>>> store it (Ohm-contrib 0.*) which looks like this "2011-02-25 21:54:06 UTC",
>>>> and the new way, which are UNIX timestamps.
>>>> I could always just make a list of the models manually and loop through them,
>>>> but I want to make a reusable script that others can benefit from as well.
>>>> Ronny.
>>>> _______________________________________________
>>>> Chat mailing list
>>>> Chat at lists.lrug.org
>>>> http://lists.lrug.org/listinfo.cgi/chat-lrug.org
>>> 
>> 
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