Class: Agent::Selector

Inherits:
Object
  • Object
show all
Defined in:
lib/agent/selector.rb

Defined Under Namespace

Classes: Case

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Selector

Returns a new instance of Selector.



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# File 'lib/agent/selector.rb', line 21

def initialize
  @ordered_cases = []
  @cases         = {}
  @operations    = {}
  @blocking_once = BlockingOnce.new
  @notifier      = Notifier.new
  @default_case  = nil
  @selected      = false
end

Instance Attribute Details

#cases ⇒ Object (readonly)

Returns the value of attribute cases.



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# File 'lib/agent/selector.rb', line 17

def cases
  @cases
end

Instance Method Details

#case(chan, direction, value = nil, &blk) ⇒ Object

Raises:



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# File 'lib/agent/selector.rb', line 45

def case(chan, direction, value=nil, &blk)
  raise "invalid case, must be a channel" unless chan.is_a?(Channel)
  raise Errors::InvalidDirection if direction != :send && direction != :receive
  add_case(chan, direction, value, &blk)
end

#default(&blk) ⇒ Object 



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# File 'lib/agent/selector.rb', line 31

def default(&blk)
  if @default_case
    raise Errors::DefaultCaseAlreadyDefinedError
  else
    @default_case = self.case(channel!(TrueClass, 1), :receive, &blk)
  end
end

#select ⇒ Object 



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# File 'lib/agent/selector.rb', line 51

def select
  raise Errors::AlreadySelectedError if @selected

  if !@ordered_cases.empty?
    @ordered_cases.each do |cse|
      if cse.direction == :send
        @operations[cse.channel] << cse.channel.send(cse.value, :uuid => cse.uuid,
                                                                :blocking_once => @blocking_once,
                                                                :notifier => @notifier,
                                                                :deferred => true)
      else # :receive || :timeout
        @operations[cse.channel] << cse.channel.receive(:uuid => cse.uuid,
                                                        :blocking_once => @blocking_once,
                                                        :notifier => @notifier,
                                                        :deferred => true)
      end
    end

    if @default_case
      @default_case.channel.send(true, :uuid => @default_case.uuid, :blocking_once => @blocking_once, :notifier => @notifier, :deferred => true)
    end

    @notifier.wait

    execute_case(@notifier.payload)
  end
ensure
  @selected = true
  close_default_channel
  dequeue_operations
end

#timeout(t, &blk) ⇒ Object 



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# File 'lib/agent/selector.rb', line 39

def timeout(t, &blk)
  s = channel!(TrueClass, 1)
  go!{ sleep t; s.send(true); s.close }
  add_case(s, :timeout, &blk)
end