123456789_123456789_123456789_123456789_123456789_

Class: Queue

Relationships & Source Files
Inherits: Object
Defined in: thread_sync.c,
thread_sync.c

Overview

This class provides a way to synchronize communication between threads.

Example:

require 'thread'
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

Class Method Summary

  • .new constructor

    Creates a new queue instance.

Instance Attribute Summary

Instance Method Summary

Constructor Details

.new

Creates a new queue instance.

Instance Attribute Details

#closed? ⇒ Boolean (readonly)

Returns true if the queue is closed.

#empty? ⇒ Boolean (readonly)

Returns true if the queue is empty.

Instance Method Details

#push(object) #enq(object) #<<(object)
Also known as: #push, #enq

Pushes the given object to the queue.

#clear

Removes all objects from the queue.

#close

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 return nil.

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

::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

#pop(non_block = false) #deq(non_block = false) #shift(non_block = false)
Also known as: #pop, #shift

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 an exception is raised.

#push(object) #enq(object) #<<(object)

Alias for #<<.

#length #size
Also known as: #size

Returns the length of the queue.

#num_waiting

Returns the number of threads waiting on the queue.

#pop(non_block = false) #deq(non_block = false) #shift(non_block = false)

Alias for #deq.

#push(object) #enq(object) #<<(object)

Alias for #<<.

#pop(non_block = false) #deq(non_block = false) #shift(non_block = false)

Alias for #deq.

#length #size

Alias for #length.