On Wed, Oct 7, 2015 at 4:26 PM, Robert Wilton <[email protected]> wrote:
> Hi Endre, > > Thanks for the explanation. > > I was struggling to see why it was necessary for the flow to effectively > generate an object as a side-effect of the materialization. > > I guess that this is a corollary of choosing a design where the elements > of the flow are created indirectly (and hence you don't have direct access > to the underlying objects that have been created). > Yes, basically everything in Akka Streams is a "FactoryBuilder" since the DSLs build not the running thing but a factory for the running thing ;) This implies certain API design choices. -Endre > > Thanks again, > Rob > > > > On 06/10/2015 14:40, Endre Varga wrote: > > Hi Robert, > > > > On Tue, Oct 6, 2015 at 3:29 PM, Robert Wilton <[email protected]> wrote: > >> Hi, >> >> I've been keeping an eye on the development of akka streams, and I was >> just taking a second look at it now. >> >> There is one thing that I can't seem to get my head around, which is the >> explicit types associated with materialization. >> >> Compared to the earlier beta versions, it feels to me that the adding >> explicit materialization types seems to have added quite a lot of >> complexity in the APIs for building and using flows and I can't see where >> they are particularly beneficial in the general case. >> > > They also removed quite a bit of complexity though: > > - more complex modules that needed to expose a materialized value needed > to also expose the internal Sources/Sinks to the outside world, since those > were keys to the MaterializedMap. Removal of this problem alone simplified > the TCP interfaces greatly. > - Only Sinks and Sources could have a materialized value before. This is > no longer the case, and this is used already. > - due to the MaterializedMap actually being, well, a Map, you cannot > reuse the same Source/Sink twice in the same graph otherwise one would > overwrite the others value in a non-deterministic (hash code dependent) > manner > - due to atomic (non-composite) Sink/Source being the keys to that map, > it was not possible to use a transformed version of them and still access > the value. > > The added type-safety is just a nice bonus on top of these. > > >> >> Presumably there was a compelling argument for adding them - I just can't >> figure out what it is! ;-) >> > > If I need to summarize the above, incomplete list, then the short answer > is: composability. The previous map-based model breaked down for anything > non-trivial, while the current one, complex or not, actually works ;) > > -Endre > > >> >> Thanks, >> Rob >> >> >> >> >> >> >> >> -- >> >>>>>>>>>> Read the docs: http://akka.io/docs/ >> >>>>>>>>>> Check the FAQ: >> http://doc.akka.io/docs/akka/current/additional/faq.html >> >>>>>>>>>> Search the archives: https://groups.google.com/group/akka-user >> --- >> You received this message because you are subscribed to the Google Groups >> "Akka User List" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to <[email protected]> >> [email protected]. >> To post to this group, send email to <[email protected]> >> [email protected]. >> Visit this group at http://groups.google.com/group/akka-user. >> For more options, visit https://groups.google.com/d/optout. >> > > -- > >>>>>>>>>> Read the docs: <http://akka.io/docs/>http://akka.io/docs/ > >>>>>>>>>> Check the FAQ: > <http://doc.akka.io/docs/akka/current/additional/faq.html> > http://doc.akka.io/docs/akka/current/additional/faq.html > >>>>>>>>>> Search the archives: > <https://groups.google.com/group/akka-user> > https://groups.google.com/group/akka-user > --- > You received this message because you are subscribed to a topic in the > Google Groups "Akka User List" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/akka-user/jtIq7GSEIaE/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/akka-user. > For more options, visit https://groups.google.com/d/optout. > > > -- > >>>>>>>>>> Read the docs: http://akka.io/docs/ > >>>>>>>>>> Check the FAQ: > http://doc.akka.io/docs/akka/current/additional/faq.html > >>>>>>>>>> Search the archives: https://groups.google.com/group/akka-user > --- > You received this message because you are subscribed to the Google Groups > "Akka User List" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/akka-user. > For more options, visit https://groups.google.com/d/optout. > -- >>>>>>>>>> Read the docs: http://akka.io/docs/ >>>>>>>>>> Check the FAQ: >>>>>>>>>> http://doc.akka.io/docs/akka/current/additional/faq.html >>>>>>>>>> Search the archives: https://groups.google.com/group/akka-user --- You received this message because you are subscribed to the Google Groups "Akka User List" group. 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