From: 7stud -- <bbxx789_05ss@...>
Date: 2009-02-17T23:14:51+09:00
Subject: Re: Ruby Threading question Creating 4 threads

Robert Klemme wrote:
> On 17.02.2009 04:38, Julian Leviston wrote:
>> Put a while around the pop and block of code to run.
> 
> Also class Queue has thread safety built in already.
> 
> Kind regards
> 
>   robert

...an example of using a Queue:

require 'thread'

arr = %w[a b c d e f g h i j]
num_threads = 4
q = Queue.new

workers = []

num_threads.times do |i|
  workers << Thread.new("worker#{i+1}") do |name|
    loop do
      data = q.pop    #pops data off bottom of q, blocks if no data
      puts "#{name} retrieved data: #{data}"
      break if data == "*END_OF_DATA_FLAG*"
    end
  end
end

arr.each {|item| q.push(item)}
num_threads.times do
  q.push("*END_OF_DATA_FLAG*")
end

workers.each {|thr| thr.join}
puts "Workers are all done working."


--output:--
worker1 retrieved data: a
worker2 retrieved data: b
worker3 retrieved data: c
worker4 retrieved data: d
worker1 retrieved data: e
worker2 retrieved data: f
worker3 retrieved data: g
worker4 retrieved data: h
worker1 retrieved data: i
worker2 retrieved data: j
worker3 retrieved data: *END_OF_DATA_FLAG*
worker4 retrieved data: *END_OF_DATA_FLAG*
worker1 retrieved data: *END_OF_DATA_FLAG*
worker2 retrieved data: *END_OF_DATA_FLAG*
Workers are all done working.

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