Class

The Queue class implements multi-producer, multi-consumer queues. It is especially useful in threaded programming when information must be exchanged safely between multiple threads. The Queue class implements all the required locking semantics.

The class implements FIFO type of queue. In a FIFO queue, the first tasks added are the first retrieved.

Example:

queue = Queue.new

producer = Thread.new do
  5.times do |i|
     sleep rand(i) # simulate expense
     queue << i
     puts "#{i} produced"
  end
end

consumer = Thread.new do
  5.times do |i|
     value = queue.pop
     sleep rand(i/2) # simulate expense
     puts "consumed #{value}"
  end
end

consumer.join

<<

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No documentation available

clear

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Removes all objects from the queue.

Closes the queue. A closed queue cannot be re-opened.

After the call to close completes, the following are true:

  • closed? will return true

  • close will be ignored.

  • calling enq/push/<< will raise a ClosedQueueError.

  • when empty? is false, calling deq/pop/shift will return an object from the queue as usual.

  • when empty? is true, deq(false) will not suspend the thread and will return nil. deq(true) will raise a ThreadError.

ClosedQueueError is inherited from StopIteration, so that you can break loop block.

Example:

    q = Queue.new
    Thread.new{
      while e = q.deq # wait for nil to break loop
        # ...
      end
    }
    q.close

Returns true if the queue is closed.

deq

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No documentation available

Returns true if the queue is empty.

enq

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No documentation available

Returns the length of the queue.

new

::

Creates a new queue instance.

num_waiting

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Returns the number of threads waiting on the queue.

Retrieves data from the queue.

If the queue is empty, the calling thread is suspended until data is pushed onto the queue. If non_block is true, the thread isn't suspended, and ThreadError is raised.

Pushes the given object to the queue.

shift

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No documentation available

size

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No documentation available