# Copyright: Copyright (c) 2004  Nicolas Despres. All rights reserved.
# Author: Nicolas Despres  <polrop@lrde.epita.fr>.
# License: Gnu General Public License.

# $LastChangedBy: ertai $
# $Id: spring_set.rb 186 2005-04-03 00:07:45Z ertai $


require 'spring'


class SpringSet

  def initialize(*springs)
    @springs = {}
    springs.flatten.each do |s|
      @springs[s.object_id] = {
        :spring => s,
        :num_collecter => s.num_collecter,
        :size => s.size
      }
      s.add_observer(self)
    end
  end

  def update(spring_id, msg, collecter_id)
    case msg
    when Spring::SIGN_UP
      @springs[spring_id][:num_collecter] += 1
    when Spring::GET
      @springs[spring_id][:size] -= 1 if @springs[spring_id][:size] > 0
    end
  end

  def get_most_free
    calc_stat(:num_collecter) { |a, b| a < b }
  end

  def get_most_busy
    calc_stat(:num_collecter) { |a, b| a > b }
  end

  def get_most_full
    calc_stat(:size) { |a, b| a > b }
  end

  def get_most_empty
    calc_stat(:size) { |a, b| a < b }
  end

  def size
    @springs.size
  end

  alias length size

  def num_collecter(spring_id)
    @springs[spring_id][:num_collecter]
  end

  def spring_size(spring_id)
    @springs[spring_id][:size]
  end

  alias spring_length spring_size

  def each
    @springs.values.each { |v| yield(v[:spring]) }
  end

  protected
  def calc_stat(field, &cmp)
    spring = nil
    @springs.values.each do |s|
      if spring.nil? or cmp[s[field], spring[field]]
        spring = s
      end
    end
    return spring[:spring]
  end

end # class SpringSet


#
# Unit test suite
#
if defined? TEST_MODE or $0 == __FILE__


require 'test/unit/ui/yaml/testrunner'


class SpringSetTest < Test::Unit::TestCase

  #
  # tests
  #
  def test_simple
    s1 = Spring.new('hello', 'world')
    s2 = Spring.new('bonjour', 'tout', 'monde')
    s = SpringSet.new(s1, s2)
    assert_equal(s1.num_collecter, s.num_collecter(s1.object_id))
    assert_equal(s2.num_collecter, s.num_collecter(s2.object_id))
    assert_equal(s1.size, s.spring_size(s1.object_id))
    assert_equal(s2.length, s.spring_length(s2.object_id))
    thread = Thread.new do
      sleep(0.0001)
      assert_equal(2, s.size)
      assert_equal(2, s.length)
      assert_equal(s2, s.get_most_full)
      assert_equal(s1, s.get_most_empty)
      s1.sign_up(thread.object_id)
      assert_equal(s1.num_collecter, s.num_collecter(s1.object_id))
      assert_equal(s1, s.get_most_busy)
      assert_equal(s2, s.get_most_free)
      s2.sign_up(thread.object_id)
      assert_equal(s2.num_collecter, s.num_collecter(s2.object_id), 'bad num collecter')
      assert_equal('bonjour', s2.get(thread.object_id))
      assert_equal(s2.size, s.spring_size(s2.object_id), 'bad size')
      assert_equal('tout', s2.get(thread.object_id))
      assert_equal(s2.size, s.spring_size(s2.object_id))
      assert_equal('monde', s2.get(thread.object_id))
      assert_equal(s2.size, s.spring_size(s2.object_id))
      assert_equal(nil, s2.get(thread.object_id))
      assert_equal(s2.size, s.spring_size(s2.object_id))
      assert_equal(0, s.spring_size(s2.object_id))
      assert_equal(s1, s.get_most_full)
      assert_equal(s2, s.get_most_empty)
    end
    thread.join
  end

end # class SpringSetTest


end