Class: Tap::App::Queue

Inherits:
Monitor
  • Object
show all
Defined in:
lib/tap/app/queue.rb

Overview

Queue allows thread-safe enqueing and dequeing of tasks and inputs for execution.

API

The following methods are required in alternative implementations of an applicaton queue, where a job is a [task, input] array:

enq(task, input)      # pushes the job onto the queue
unshift(task, input)  # unshifts the job onto the queue
deq                   # shifts a job off the queue
size                  # returns the number of jobs in the queue
clear                 # clears the queue, returns current jobs
synchronize           # yields to the block
to_a                  # returns the queue as an array

Note that synchronize must be implemented even if it does nothing but yield to the block.

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Queue

Creates a new Queue



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# File 'lib/tap/app/queue.rb', line 27

def initialize
  super
  @queue = []
end

Instance Method Details

#clear ⇒ Object

Clears self and returns an array of the currently enqueued jobs.



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# File 'lib/tap/app/queue.rb', line 59

def clear
  synchronize do
    current = @queue
    @queue = []
    current
  end
end

#deq ⇒ Object

Dequeues the next job. Returns nil if the queue is empty.



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# File 'lib/tap/app/queue.rb', line 47

def deq
  synchronize { @queue.shift }
end

#enq(task, input) ⇒ Object

Enqueues the task and input.



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# File 'lib/tap/app/queue.rb', line 33

def enq(task, input)
  synchronize do
    @queue.push [task, input]
  end
end

#size ⇒ Object

Returns the number of enqueued jobs.



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# File 'lib/tap/app/queue.rb', line 52

def size
  synchronize do
    @queue.size
  end
end

#to_a ⇒ Object

Returns the enqueued jobs as an array.



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# File 'lib/tap/app/queue.rb', line 68

def to_a
  synchronize do
    @queue.dup
  end
end

#unshift(task, input) ⇒ Object

Enqueues the task and input, but to the top of the queue.



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# File 'lib/tap/app/queue.rb', line 40

def unshift(task, input)
  synchronize do
    @queue.unshift [task, input]
  end
end