This expression is a cross between ‘concurrence’ and ‘iterator’.

  pdef = Ruote.process_definition :name => 'test' do
    concurrent_iterator :on_val => 'alice, bob, charly', :to_var => 'v' do
      participant '${v:v}'
    end
  end

will be equivalent to

  pdef = Ruote.process_definition :name => 'test' do
    concurrence do
      participant 'alice'
      participant 'bob'
      participant 'charly'
    end
  end

The ‘on’ and the ‘to’ attributes follow exactly the ones for the iterator expression.

When there is no ‘to’, the current iterated value is placed in the variable named ‘i’.

The variable named ‘ii’ contains the current iterated index (an int bigger or egal to 0).

‘concurrent_iterator’ does not understand commands like rewind/break/jump/… like ‘iterator’ does, since it fires all its branches when applied.

:times and :branches

Similarly to the iterator expression, the :times or the :branches attribute may be used in stead of the ‘on’ attribute.

  pdef = Ruote.process_definition :name => 'test' do
    concurrent_iterator :times => 3 do
      participant 'user${v:i}'
    end
  end

is equivalent to

  pdef = Ruote.process_definition :name => 'test' do
    concurrence do
      participant 'user0'
      participant 'user1'
      participant 'user2'
    end
  end

options

the concurrent_iterator accepts the same options for merging as its bigger brother, the concurrence expression.

:count, :merge (override, mix, isolate), remaining (cancel, forget) and :over.

add branches

The ‘add_branches’/’add_branch’ expression can be used to add branches to a concurrent-iterator while it is running.

  concurrent_iterator :on => 'a, b, c' do
    sequence do
      participant :ref => 'worker_${v:i}'
      add_branches 'd, e', :if => '${v:/not_sufficient}'
    end
  end

In this example, if the process level variable ‘not_sufficient’ is set to true, workers d and e will be added to the iterated elements.

Read more at the ‘add_branches’ expression description.