Class: XThread::RBSizedQueue

Inherits:
RBQueue
  • Object
show all
Defined in:
lib/xthread.rb

Overview

This class represents queues of specified size capacity. The push operation may be blocked if the capacity is full.

See Queue for an example of how a SizedQueue works.

Instance Method Summary collapse

Methods inherited from RBQueue

#clear, #empty?, #length

Constructor Details

#initialize(max) ⇒ RBSizedQueue

Creates a fixed-length queue with a maximum size of max.

Raises:

  • (ArgumentError) 


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# File 'lib/xthread.rb', line 158

def initialize(max)
  raise ArgumentError, "queue size must be positive" unless max > 0
  @max = max
  @cond_wait = ConditionVariable.new
  super()
end

Instance Method Details

#max ⇒ Object

Returns the maximum size of the queue.



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# File 'lib/xthread.rb', line 168

def max
  @max
end

#max=(max) ⇒ Object

Sets the maximum size of the queue.



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# File 'lib/xthread.rb', line 175

def max=(max)
  diff = nil
  @mutex.synchronize {
	if max <= @max
	  @max = max
	else
	  diff = max - @max
	  @max = max
	end
  }
  if diff
	diff.times do
	  @cond_wait.signal
	end
  end
  max
end

#pop(*args) ⇒ Object Also known as: shift, deq

Retrieves data from the queue and runs a waiting thread, if any.



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# File 'lib/xthread.rb', line 222

def pop(*args)
  retval = super
  @mutex.synchronize {
	if @que.length < @max
	  @cond_wait.signal
	end
  }
  retval
end

#push(obj) ⇒ Object Also known as: <<, enq

Pushes obj to the queue. If there is no space left in the queue, waits until space becomes available.



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# File 'lib/xthread.rb', line 197

def push(obj)
  @mutex.synchronize{
	while true
	  break if @que.length < @max
	  @cond_wait.wait(@mutex)
	end

	@que.push obj
	@cond.signal
  }
end