Class: GirlFriday::Batch

Inherits:
Object
  • Object
show all
Defined in:
lib/girl_friday/batch.rb

Overview

Batch represents a set of operations which can be processed concurrently. Asking for the results of the batch acts as a barrier: the calling thread will block until all operations have completed. Results are guaranteed to be returned in the same order as the operations are given.

Internally a girl_friday queue is created which limits the number of concurrent operations based on the :size option.

TODO Errors are not handled well at all.

Instance Method Summary collapse

Constructor Details

#initialize(enumerable = nil, options = {}, &block) ⇒ Batch

Returns a new instance of Batch.



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# File 'lib/girl_friday/batch.rb', line 15

def initialize(enumerable=nil, options={}, &block)
  @queue = GirlFriday::Queue.new(:batch, options, &block)
  @complete = 0
  @size = 0
  @results = []
  if enumerable
    @size = enumerable.count
    @results = Array.new(@size)
  end
  @lock = Mutex.new
  @condition = ConditionVariable.new
  @frozen = false
  start(enumerable)
end

Instance Method Details

#push(msg) ⇒ Object Also known as: <<

Raises:

  • (ArgumentError) 


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# File 'lib/girl_friday/batch.rb', line 39

def push(msg)
  raise ArgumentError, "Batch is frozen, you cannot push more items into it" if @frozen
  @lock.synchronize do
    @results << nil
    @size += 1
    index = @results.size - 1
    @queue.push(msg) do |result|
      completion(result, index)
    end
  end
end

#results(timeout = nil) ⇒ Object 



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# File 'lib/girl_friday/batch.rb', line 30

def results(timeout=nil)
  @frozen = true
  @lock.synchronize do
    @condition.wait(@lock, timeout) if @complete != @size
    @queue.shutdown
    @results
  end
end