Class: Async::LimitedQueue

Inherits:
Queue
  • Object
show all
Defined in:
lib/async/queue.rb

Overview

A queue which limits the number of items that can be enqueued.

Instance Attribute Summary collapse

Attributes inherited from Queue

#The items in the queue., #items

Instance Method Summary collapse

Methods inherited from Queue

#<<, #async, #each, #empty?, #pop, #signal, #size, #wait

Constructor Details

#initialize(limit = 1, full: Notification.new, **options) ⇒ LimitedQueue

Create a new limited queue.

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# File 'lib/async/queue.rb', line 112

def initialize(limit = 1, full: Notification.new, **options)
	super(**options)
	
	@limit = limit
	@full = full
end

Instance Attribute Details

#limit ⇒ Object (readonly)

Returns the value of attribute limit.


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# File 'lib/async/queue.rb', line 120

def limit
  @limit
end

#The maximum number of items that can be enqueued.(maximumnumberofitemsthatcanbeenqueued.) ⇒ Object (readonly) 


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# File 'lib/async/queue.rb', line 120

attr :limit

Instance Method Details

#dequeue ⇒ Object

Remove and return the next item from the queue.

If the queue is empty, this method will block until an item is available.

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# File 'lib/async/queue.rb', line 163

def dequeue
	item = super
	
	@full.signal
	
	return item
end

#enqueue(*items) ⇒ Object

Add multiple items to the queue.

If the queue is full, this method will block until there is space available.

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# File 'lib/async/queue.rb', line 145

def enqueue(*items)
	while !items.empty?
		while limited?
			@full.wait
		end
		
		available = @limit - @items.size
		@items.concat(items.shift(available))
		
		@available.signal unless self.empty?
	end
end

#limited? ⇒ Boolean

Returns:

  • (Boolean)
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# File 'lib/async/queue.rb', line 123

def limited?
	@items.size >= @limit
end

#push(item) ⇒ Object

Add an item to the queue.

If the queue is full, this method will block until there is space available.

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# File 'lib/async/queue.rb', line 132

def push(item)
	while limited?
		@full.wait
	end
	
	super
end