From: Abhijit Sarkar <lists@...>
Date: 2013-02-14T12:50:48+09:00
Subject: Ruby Multithreaded producer-consumer problem

Hi,
I started on Ruby less than a week ago but have already come to
appreciate the power of the language. I am trying my hands on a classic
producer-consumer problem, implemented as an Orange tree (c.f.
http://pine.fm/LearnToProgram/?Chapter=09). The Orange tree grows each
year until it dies and produces a random number of Oranges each year
(Producer). Oranges can be picked as long there are any on the tree
(Consumer).

I've got two problems here:

1) The attached code gives me the following exception:
/Users/Abhijit/Workspace/eclipse/ruby/learn_to_program/orange_tree.rb:84:
warning: instance variable @orange_tree not initialized
/Users/Abhijit/Workspace/eclipse/ruby/learn_to_program/orange_tree.rb:84:in
`<class:Worker>': undefined method `age' for nil:NilClass
(NoMethodError)
  from
/Users/Abhijit/Workspace/eclipse/ruby/learn_to_program/orange_tree.rb:45:in
`<main>'

2) I am not sure that the multithreading part is correctly coded.

Any help is very much appreciated. I've got myself a couple of books,
including "Programming Ruby" and "The Ruby Programming Language" but
none of them contain a true "producer-consumer problem".

Attachments:
http://www.ruby-forum.com/attachment/8127/orange_tree.rb


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