If you need the results from the substreams you’ll have to merge them back into the mainstream and aggregate them there:
transactions.groupBy(100, ...).fold(...).mergeSubstreams.grouped(100).to(Sink.head) Regards, Roland > 26 apr 2016 kl. 17:36 skrev debasish <ghosh.debas...@gmail.com>: > > Viktor - > > Here's the same stuff that works for akka-streams version > akka-stream-experimental 1.0 RC4. .. > https://gist.github.com/debasishg/4d596c1f26d4759ed65e281bb2e6fd2c .. > > The upgrade that I am having trouble with is defining netTxn (pls see the > gist). The groupBy works like a charm in the older version. But in the newer > version it returns a Subflow and I was stumped how to get hold of each of the > substreams and fold them using a Monoid on a fold sink. Konrad's solution was > to use the to method of subflow. But somehow it's not giving the desired > result .. help ? > > Thanks. > > > On Tuesday, April 26, 2016 at 8:46:11 PM UTC+5:30, √ wrote: > What are you expecting to be returned? > > -- > Cheers, > √ > > On Apr 26, 2016 3:49 PM, "Debasish Ghosh" <ghosh.d...@gmail.com > <javascript:>> wrote: > Thanks Konrad for the pointer .. when I run the graph I get a NotUsed .. > That's not hwat I get with the earlier implementation. Please have a look at > the gist .. > https://gist.github.com/debasishg/a42e867bb2bc8ad18243597178bbce93 > <https://gist.github.com/debasishg/a42e867bb2bc8ad18243597178bbce93> .. what > am I doing wrong. > > Thanks. > > On Tue, Apr 26, 2016 at 6:22 PM, Konrad Malawski <konrad....@typesafe.com > <javascript:>> wrote: > (I did a quick mock Transaction type, your Monoid should work fine there ofc). > > -- Konrad > > On Sunday, 24 April 2016 21:42:43 UTC+2, debasish wrote: > Hi - > > I am trying to migrate some akka-streams code from an earlier version > (akka-stream-experimental 1.0.RC4) .. please have a look at the following .. > > /** > * Create multiple streams out of a single stream. The stream "transactions" > is being > * demultiplexed into many streams split by account number. Each of the > sub-streams are > * then materialized to the fold sink "txnSink", which folds each of the > transaction > * substreams to compute the net value of the transaction for that account > */ > val netTxn: Source[RunnableGraph[Future[Transaction]], Unit] = > transactions.map(validate).groupBy(_.accountNo).map { case (a, s) => > s.toMat(txnSink)(Keep.right) } > > I am trying to create substreams based on a field accountNo within a > Transaction. Then I pass each substream to toMat with a Sink which is a fold > Sink defined as below .. > > /** > * Would like to fold transactions through monoid append > */ > val txnSink: Sink[Transaction, Future[Transaction]] = > Sink.fold[Transaction, Transaction](TransactionMonoid.zero)(_ |+| _) > > The idea is to apply a monoid over each substream and do some netting on > transactions belonging to the same accountNo. > > How can I migrate this to 2.4.4 ? Now groupBy returns a Subflow and I am not > sure how to apply each of the substreams to the materializer. One option that > works will be to create a Map[String, Transaction] upfront and then directly > apply the monoid to the Map in the main stream and not create any substream. > But I would like to have the substreams fro some other purpose as well. > > Any help will be appreciated .. > > Regards. > - Debasish > > > > > > -- > >>>>>>>>>> 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/YhJfghLqnhw/unsubscribe > <https://groups.google.com/d/topic/akka-user/YhJfghLqnhw/unsubscribe>. > To unsubscribe from this group and all its topics, send an email to > akka-user+...@googlegroups.com <javascript:>. > To post to this group, send email to akka...@googlegroups.com <javascript:>. > Visit this group at https://groups.google.com/group/akka-user > <https://groups.google.com/group/akka-user>. > For more options, visit https://groups.google.com/d/optout > <https://groups.google.com/d/optout>. > > > > -- > Debasish Ghosh > http://manning.com/ghosh2 <http://manning.com/ghosh2> > http://manning.com/ghosh <http://manning.com/ghosh> > > Twttr: @debasishg > Blog: http://debasishg.blogspot.com <http://debasishg.blogspot.com/> > Code: http://github.com/debasishg <http://github.com/debasishg> > > -- > >>>>>>>>>> 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 the Google Groups > "Akka User List" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to akka-user+...@googlegroups.com <javascript:>. > To post to this group, send email to akka...@googlegroups.com <javascript:>. > Visit this group at https://groups.google.com/group/akka-user > <https://groups.google.com/group/akka-user>. > For more options, visit https://groups.google.com/d/optout > <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 the Google Groups > "Akka User List" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to akka-user+unsubscr...@googlegroups.com > <mailto:akka-user+unsubscr...@googlegroups.com>. > To post to this group, send email to akka-user@googlegroups.com > <mailto:akka-user@googlegroups.com>. > Visit this group at https://groups.google.com/group/akka-user > <https://groups.google.com/group/akka-user>. > For more options, visit https://groups.google.com/d/optout > <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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