Class: Eurydice::ConcurrentColumnEnumerator

Inherits:
ColumnEnumeratorBase show all
Defined in:
lib/eurydice/column_enumerator.rb

Instance Method Summary collapse

Methods inherited from ColumnEnumeratorBase

#each

Constructor Details

#initialize(*args) ⇒ ConcurrentColumnEnumerator

Returns a new instance of ConcurrentColumnEnumerator.



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# File 'lib/eurydice/column_enumerator.rb', line 67

def initialize(*args)
  super
  @standard_enumerator = ColumnEnumerator.new(*args)
  @queue = ArrayBlockingQueue.new(@options[:max_column_count] * 2)
  @fetch_pool = Executors.new_single_thread_executor(DaemonThreadFactory.new(self.class.name))
  @exhausted = true
  rewind
end

Instance Method Details

#next ⇒ Object

Raises:

  • (StopIteration) 


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# File 'lib/eurydice/column_enumerator.rb', line 76

def next
  unless @running.get_and_set(true)
    @fetch_pool.execute do
      begin
        while @running.get
          pair = @standard_enumerator.next
          @queue.put(pair)
        end
      rescue StopIteration
      end
      @queue.put(:stop_iteration)
    end
  end
  
  raise StopIteration if @exhausted
    
  value = @queue.take
  if value == :stop_iteration
    @exhausted = true
    raise StopIteration
  end

  value
end

#rewind ⇒ Object 



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# File 'lib/eurydice/column_enumerator.rb', line 101

def rewind
  @running = AtomicBoolean.new(false)
  unless @exhausted
    until @queue.take == :stop_iteration; end
  end
  @standard_enumerator.rewind
  @exhausted = false
end