Class: Async::Barrier

Inherits:

Object

• Object
• Async::Barrier

Defined in:

lib/async/barrier.rb

Overview

A general purpose synchronisation primitive, which allows one task to wait for a number of other tasks to complete. It can be used in conjunction with Semaphore.

Instance Attribute Summary

• #tasks ⇒ Object readonly

  All tasks which have been invoked into the barrier.

Instance Method Summary

• #async(*arguments, parent: (@parent or Task.current), **options, &block) ⇒ Object

  Execute a child task and add it to the barrier.

• #empty? ⇒ Boolean

  Whether there are any tasks being held by the barrier.

• #initialize(parent: nil) ⇒ Barrier constructor

  Initialize the barrier.

• #size ⇒ Object

  Number of tasks being held by the barrier.

• #stop ⇒ Object

  Stop all tasks held by the barrier.

• #wait ⇒ Object

  Wait for all tasks to complete by invoking Task#wait on each waiting task, which may raise an error.

Constructor Details

#initialize(parent: nil) ⇒ Barrier

Initialize the barrier.

# File 'lib/async/barrier.rb', line 17

def initialize(parent: nil)
	@tasks = List.new
	
	@parent = parent
end

Instance Attribute Details

#tasks ⇒ Object (readonly)

All tasks which have been invoked into the barrier.

# File 'lib/async/barrier.rb', line 39

def tasks
  @tasks
end

Instance Method Details

#async(*arguments, parent: (@parent or Task.current), **options, &block) ⇒ Object

Execute a child task and add it to the barrier.

# File 'lib/async/barrier.rb', line 43

def async(*arguments, parent: (@parent or Task.current), **options, &block)
	task = parent.async(*arguments, **options, &block)
	
	@tasks.append(TaskNode.new(task))
	
	return task
end

#empty? ⇒ Boolean

Whether there are any tasks being held by the barrier.

Returns:

• (Boolean)

# File 'lib/async/barrier.rb', line 53

def empty?
	@tasks.empty?
end

#size ⇒ Object

Number of tasks being held by the barrier.

# File 'lib/async/barrier.rb', line 34

def size
	@tasks.size
end

#stop ⇒ Object

Stop all tasks held by the barrier.

# File 'lib/async/barrier.rb', line 72

def stop
	@tasks.each do |waiting|
		waiting.task.stop
	end
end

#wait ⇒ Object

Wait for all tasks to complete by invoking Task#wait on each waiting task, which may raise an error. As long as the task has completed, it will be removed from the barrier.

# File 'lib/async/barrier.rb', line 59

def wait
	@tasks.each do |waiting|
		task = waiting.task
		begin
			task.wait
		ensure
			@tasks.remove?(waiting) unless task.alive?
		end
	end
end