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+doc add more docs on CoupledTerminationFlow

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Konrad `ktoso` Malawski 2017-02-13 14:21:45 +01:00
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akka-docs/rst/scala/stream/stages-overview.rst
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@ -859,6 +859,47 @@ number of times. Each time a failure is fed into the partial function and a new
**completes** when upstream completes or upstream failed with exception provided partial function can handle
Flow stages composed of Sinks and Sources
-----------------------------------------
Flow.fromSinkAndSource
^^^^^^^^^^^^^^^^^^^^^^
Creates a ``Flow`` from a ``Sink`` and a ``Source`` where the Flow's input will be sent to the ``Sink``
and the ``Flow`` 's output will come from the Source.
Note that termination events, like completion and cancelation is not automatically propagated through to the "other-side"
of the such-composed Flow. Use ``CoupledTerminationFlow`` if you want to couple termination of both of the ends,
for example most useful in handling websocket connections.
CoupledTerminationFlow.fromSinkAndSource
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Allows coupling termination (cancellation, completion, erroring) of Sinks and Sources while creating a Flow them them.
Similar to ``Flow.fromSinkAndSource`` however that API does not connect the completion signals of the wrapped stages.
Similar to ``Flow.fromSinkAndSource`` however couples the termination of these two stages.
E.g. if the emitted ``Flow`` gets a cancellation, the ``Source`` of course is cancelled,
however the Sink will also be completed. The table below illustrates the effects in detail:
+-------------------------------------------------+-----------------------------+---------------------------------+
| Returned Flow | Sink (in) | Source (out) |
+=================================================+=============================+=================================+
| cause: upstream (sink-side) receives completion | effect: receives completion | effect: receives cancel |
+-------------------------------------------------+-----------------------------+---------------------------------+
| cause: upstream (sink-side) receives error | effect: receives error | effect: receives cancel |
+-------------------------------------------------+-----------------------------+---------------------------------+
| cause: downstream (source-side) receives cancel | effect: completes | effect: receives cancel |
+-------------------------------------------------+-----------------------------+---------------------------------+
| effect: cancels upstream, completes downstream | effect: completes | cause: signals complete |
+-------------------------------------------------+-----------------------------+---------------------------------+
| effect: cancels upstream, errors downstream | effect: receives error | cause: signals error or throws |
+-------------------------------------------------+-----------------------------+---------------------------------+
| effect: cancels upstream, completes downstream | cause: cancels | effect: receives cancel |
+=================================================+=============================+=================================+
The order in which the `in` and `out` sides receive their respective completion signals is not defined, do not rely on its ordering.
Asynchronous processing stages
------------------------------