concurrent_iterator
This expression is a cross between ‘concurrence’ and ‘iterator’.
Please look at the documentation of ‘iterator’ to learn more about the
common options between ‘iterator’ and ‘concurrent-iterator’.
pdef = Ruote.process_definition :name => 'test' do concurrent_iterator :on_val => 'alice, bob, charly', :to_var => 'v' do participant '${v:v}' end end
will be equivalent to
pdef = Ruote.process_definition :name => 'test' do concurrence do participant 'alice' participant 'bob' participant 'charly' end end
The ‘on’ and the ‘to’ attributes follow exactly the ones for the iterator
expression.
When there is no ‘to’, the current iterated value is placed in the variable
named ‘i’.
The variable named ‘ii’ contains the current iterated index (an int bigger
or egal to 0).
‘concurrent_iterator’ does not understand commands like
rewind/break/jump/… like ‘iterator’ does, since it fires all its
branches when applied.
:on and arrays
Given a workitem field named ‘x’ containing the array value
[ ‘a’, ‘b’, ‘c’ ] and a workitem field ‘y’ containing the string ‘a, b, c’,
this:
concurrent_iterator :on_field => 'x', :to_f => 'xx' do # ... end
is equivalent to
concurrent_iterator :on => '$f:x', :to_f => 'xx' do # ... end
is equivalent to
concurrent_iterator :on => '${f:y}', :to_f => 'xx' do # ... end
:to_field and :to_f, :to_var and :to_v, :to
Those 4 lines are equivalent:
concurrent_iterator :on => [ 'ceo', 'cto' ], :to_field => 'a' do ... concurrent_iterator :on => [ 'ceo', 'cto' ], :to_f => 'a' do ... concurrent_iterator :on => [ 'ceo', 'cto' ], :to => 'f:a' do ... concurrent_iterator :on => [ 'ceo', 'cto' ], :to => 'a' do ...
Those 3 lines are equivalent:
concurrent_iterator :on => [ 'ceo', 'cto' ], :to_var => 'a' do ... concurrent_iterator :on => [ 'ceo', 'cto' ], :to_v => 'a' do ... concurrent_iterator :on => [ 'ceo', 'cto' ], :to => 'v:a' do ...
:times and :branches
Similarly to the iterator expression, the :times or the :branches attribute
may be used in stead of the ‘on’ attribute.
pdef = Ruote.process_definition :name => 'test' do concurrent_iterator :times => 3 do participant 'user${v:i}' end end
is equivalent to
pdef = Ruote.process_definition :name => 'test' do concurrence do participant 'user0' participant 'user1' participant 'user2' end end
ruote 2.3.0 and the citerator children
Prior to ruote 2.3.0, the concurrent-iterator only considered one child
expression:
concurrent_iterator :times => 3 do participant 'al' participant 'bob' # 'bob' would never be reached end
So one had to write:
concurrent_iterator :times => 3 do sequence do participant 'al' participant 'bob' # 'bob' would never be reached end end
Ruote 2.3.0 lifts that restriction.
options
the concurrent_iterator accepts the same options for merging as its bigger
brother, the concurrence expression.
:count, :merge (override, mix, isolate, stack, union, concat, deep, ignore),
: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.
‘citerator’
‘citerator’ is an alias for ‘concurrent_iterator’.
pdef = Ruote.process_definition :name => 'test' do citerator :on_val => 'alice, bob, charly', :to_var => 'v' do participant '${v:v}' end end