README.markdown

I want a connection pool for mysql objects that I would use with the mysql C adapter and mysqlplus. But I was also looking to make it as flexible as possible so that it can be a pool of object for more than just mysql connections. I'm looking for advice on how to implement that, I currently have 2 implementations above. I read the sequel connection_pool.rb file but I don't understand everything so stripping the Sequel part is kind of a problem for me. Do you guys have any advice/opinion on how I could achieve this?

pool1.rb

require 'time'
require 'thread'
require 'timeout'

class Stored
  def initialize
    @iid = object_id
    puts "#{@iid}: Created."
  end
  
  def use
    sleep(1)
    puts "#{@iid}: Used."
  end
end

class Pool
  def initialize(size, proc)
    @objects, @proc = [], proc
    @mutex = Mutex.new
    
    1.upto(size) do |i|
      @objects << proc.call
    end
  end
  
  def get
    o = nil
    
    until !o.nil?
      @mutex.synchronize {
        o = @objects.pop
      }
      sleep(0.1) if o.nil?
    end
    
    yield o
    
    @mutex.synchronize {
      @objects.push(o)
    }
    #TODO: Handle exceptions and create a new object if needed.
  end
end

pool = Pool.new(3, lambda{ Stored.new() } )

a = Time.now
threads = []
1.upto(10) do |j|
  threads << Thread.new do
    pool.get do |i|
      i.use
    end
  end
end
threads.each{|t| t.join }

puts (Time.now-a)

pool2.rb

require 'time'
require 'thread'
require 'timeout'

class Stored
  def initialize
    @iid = object_id
    puts "#{@iid}: Created."
  end
  
  def use
    sleep(1)
    puts "#{@iid}: Used."
  end
end

class Pool
  def initialize(max_size, proc)
    @max_size, @proc = max_size, proc
    @objects, @created = [], 0
    @mutex = Mutex.new
  end
  
  def get
    until o = acquire
      sleep 0.1
    end
    yield o
    release(o)
    #TODO: rescue exceptions and re-create an object if needed.
  end
  
  private
  # Tries to get an object of the @objects array or create one.
  def acquire
    o = nil
    @mutex.synchronize do
      o = @objects.pop
      if o.nil? and @created < @max_size
        @objects << @proc.call
        @created += 1
      end
    end
    o
  end
  
  def release(o)
    @mutex.synchronize{ @objects.push(o) }
  end
end

pool = Pool.new(3, lambda{ Stored.new() } )

a = Time.new
threads = []
1.upto(10) do |j|
  threads << Thread.new do
    pool.get do |i|
      i.use
    end
  end
end
threads.each{|t| t.join }

puts (Time.now-a)