Class: Class

Inherits:
Object
  • Object
show all
Defined in:
lib/nucleus/core/common/thread_config_accessor.rb

Overview

Redefines the Class and provides the thread_lib_accessor.

If invoked with a variable name, the class and its instances can be used as a key-value config for that variable name. E.g.:

class ThreadedConfig
  thread_config_accessor :some_setting, :default => 5
end

class TestThreadedConfig < Test::Unit::TestCase
  def test_that_the_accessors_work!
    # create instance
    config = ThreadedConfig.new
    # assign value to the class
    ThreadedConfig.setting_a = 1

    # value is equal for both, class and instance
    assert_equal 1, ThreadedConfig.setting_a
    assert_equal 1, config.setting_a

    # create new Thread, which should NOT have the values assigned
    Thread.new {
      config.setting_a = 2
      assert_equal 2, ThreadedConfig.setting_a
      assert_equal 2, config.setting_a
    }.join

    # create new Thread and assert the default value was assigned
    Thread.new { assert_equal 5, ThreadedConfig.setting_a }.join

    assert_equal 1, ThreadedConfig.setting_a
  end
end

By coderrr (Steve), see coderrr.wordpress.com/2008/04/10/lets-stop-polluting-the-threadcurrent-hash/

Instance Method Summary collapse

Instance Method Details

#thread_config_accessor(name, options = {}) ⇒ Object

Binds accessors to the class and its instances and allows to use them as thread-bound config



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# File 'lib/nucleus/core/common/thread_config_accessor.rb', line 38

def thread_config_accessor(name, options = {})
  mod = Module.new
  mod.module_eval do
    class_variable_set :"@@#{name}", Hash.new { |h, k| h[k] = options[:default] }
  end

  # use finalizer to prevent memory leaks and clean-up when threads die
  mod.module_eval %{
    FINALIZER = lambda {|id| @@#{name}.delete id }

    def #{name}
      @@#{name}[Thread.current.object_id]
    end

    def #{name}=(val)
      ObjectSpace.define_finalizer Thread.current, FINALIZER  unless @@#{name}.has_key? Thread.current.object_id
      @@#{name}[Thread.current.object_id] = val
    end
  }

  class_eval do
    include mod
    extend mod
  end
end

#thread_config_accessor_readonly(name, options = {}) ⇒ Object

Binds accessors to the class and its instances and allows to use them as (read-only) thread-bound config



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# File 'lib/nucleus/core/common/thread_config_accessor.rb', line 65

def thread_config_accessor_readonly(name, options = {})
  mod = Module.new
  mod.module_eval do
    class_variable_set :"@@#{name}", Hash.new { |h, k| h[k] = options[:default] }
  end

  # use finalizer to prevent memory leaks and clean-up when threads die
  mod.module_eval %{(
    FINALIZER = lambda {|id| @@#{name}.delete id }

    def #{name}
      @@#{name}[Thread.current.object_id]
    end
  )}

  class_eval do
    include mod
    extend mod
  end
end