Class: Motel::Runner

Inherits:
Object
  • Object
show all
Includes:
Singleton
Defined in:
lib/motel/runner.rb

Overview

Motel::Runner is a singleton class/object which acts as the primary mechanism to run locations in the system. It contains a thread pool which contains a specified number of threads which to move the managed locations in accordance to their location strategies.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(args = {}) ⇒ Runner

Returns a new instance of Runner.



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# File 'lib/motel/runner.rb', line 22

def initialize(args = {})
  # is set to true upon runner termination
  @terminate = false

  # TODO use ruby tree to store locations w/ heirarchy
  # management queues, locations to be scheduled and locations to be run
  @schedule_queue = []
  @run_queue = []


  # locks protecting queues from concurrent access and conditions indicating queues have items
  @schedule_lock  = Mutex.new
  @run_lock       = Mutex.new
  @schedule_cv    = ConditionVariable.new
  @run_cv         = ConditionVariable.new

  @run_thread = nil
end

Instance Attribute Details

#run_thread ⇒ Object (readonly)

For testing purposes



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# File 'lib/motel/runner.rb', line 20

def run_thread
  @run_thread
end

#terminate ⇒ Object (readonly)

For testing purposes



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# File 'lib/motel/runner.rb', line 20

def terminate
  @terminate
end

Instance Method Details

#<<(location) ⇒ Object

Wrapper around run, except return ‘self’ when done



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# File 'lib/motel/runner.rb', line 81

def <<(location)
  run(location)
  return self
end

#clear ⇒ Object

Empty the list of locations being managed/tracked



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# File 'lib/motel/runner.rb', line 49

def clear
  @schedule_lock.synchronize {
    @run_lock.synchronize {
      @schedule_queue.clear
      @run_queue.clear
  }}
end

#join ⇒ Object

Block until runner is shutdown before returning



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# File 'lib/motel/runner.rb', line 118

def join
  @run_thread.join unless @run_thread.nil?
  @run_thread = nil
end

#locations ⇒ Object

Return complete list of locations being managed/tracked



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# File 'lib/motel/runner.rb', line 42

def locations
  # need conccurrent protection here, or copy the elements into another array and return that?
  @schedule_queue + @run_queue
end

#run(location) ⇒ Object

Add location to runner to be managed, after this is called, the location’s movement strategy’s move method will be invoked periodically



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# File 'lib/motel/runner.rb', line 59

def run(location)
  @schedule_lock.synchronize {
    # autogenerate location.id if nil
    if location.id.nil?
      @run_lock.synchronize {
        i = 1
        until false
          break if @schedule_queue.find { |l| l.id == i }.nil? && @run_queue.find { |l| l.id == i }.nil?
          i += 1
        end
        location.id = i
      }
    end

    Logger.debug "adding location #{location.id} to runner queue"
    @schedule_queue.push location
    @schedule_cv.signal
  }
  return location
end

#start(args = {}) ⇒ Object

Start moving the locations. If :async => true is passed in, this will immediately return, else this will block until stop is called.



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# File 'lib/motel/runner.rb', line 88

def start(args = {})
  @num_threads = 5
  @num_threads = args[:num_threads] if args.has_key? :num_threads
  @terminate = false

  if args.has_key?(:async) && args[:async]
    Logger.debug "starting async motel runner"
    @run_thread = Thread.new { run_cycle }
  else
    Logger.debug "starting motel runner"
    run_cycle
  end

end

#stop ⇒ Object

Stop locations movement



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# File 'lib/motel/runner.rb', line 104

def stop
  Logger.debug "stopping motel runner"
  @terminate = true
  @schedule_lock.synchronize {
    @schedule_cv.signal
  }
  @run_lock.synchronize {
    @run_cv.signal
  }
  join
  Logger.debug "motel runner stopped"
end