This was the subject of the original link I sent. I actually wanted to have a lot more than just a message ID - workId, senderId, recipientId, etc... - and I didn't want to burden my "business logic" actors with having to worry about it.
The solution was, as Patrik has suggested, to use use an envelope. I just spiced it up with a bunch of implicits and such to make the pain of using the envelope go away. I'll plug it again, because I really think it might help solve your problem: http://blog.primal.com/using-scala-implicits-to-implement-a-messaging-protocol/ On Dec 18, 2013, at 2:37 AM, Patrik Nordwall <[email protected]> wrote: > > On Tue, Dec 17, 2013 at 9:39 PM, Shawn <[email protected]> wrote: > Gosh, I must have done a poor job making my point! My question is probably > more about Scala but since I'm looking for ideas on modeling related data > (messages) specifically for Akka, I posted here. > > So, my original issue is really asking how to define common data between > messages. My first reply to this thread was a naive (scala newbie) attempt at > that. > > Ideally I'd like to say something like > > case class MyMessage(foo:String) extends MessageWithId > > ... and have it act as if MyMessage was a case class defined with an id > property and preferably some implementation (implementation important, but > not for this discussion) to generate the id. So my question is about whether > we can define messages in something akin to an OO inheritance hierarchy. > > To include id in the automatic case class equals/hashCode/toString/copy the > id must be part of the first parameter list. You can sometimes benefit from > having a `trait MessageWithId { def id: ID }`, but that is for being able to > operate on id-carrying messages without having to know all message types. > > I often find it more flexible to use an envelope: > case class Envelope(id: ID, message: Any) > > Cheers, > Patrik > > > Alternately, perhaps someone can enlighten me as to why I should always > prefer to define this id property (repeatedly) on each case class message? > > e.g. MyMessage(id:something, foo:String), MyOtherMsg(id:something, > bar:String), ... > > > > I do. > > It's quite possible that this thread has gone awry :) I believe that the > original issue was probably meaning to say something like, "Are you sure that > using nanoseconds as unique identifiers isn't a terrible idea?". Of course, > to this I would certainly say "yes". And if that was what the original > question was, I probably tore this thread way off course :) > >> >> Cheers, >> √ >> >> >>> >>> Cheers, >>> √ >>> >>> >>> def genId(implicit uniqueifier: Long) = s"${uniqueifier}-${System.nanoTime}" >>> >>> Now, give each Actor an implicit uniqueifier, and then put in a guarantee >>> that no single Actor will call this more than once per nano second. e.g. >>> create enough Actors to do the work, loop until the new Id isn't the same >>> as the last one, etc... >>> >>> Or, give a each Actor a uniqueifier, and let it use a monotonically >>> increasing postfix identifier. e.g. gen the uniqueifier as a UUID and then >>> let them increment a Long until it gets exhausted, then pick another UUID, >>> or crash the Actor, or... >>> >>> Vary these themes as you see fit. "Solved" here means that I'm not being >>> all that inventive; for non-generalized situations, the above should work >>> perfectly fine. >>> >>>> >>>> Regards, >>>> >>>> Roland >>>> >>>>> >>>>>> >>>>>> -- >>>>>> >>>>>>>>>> Read the docs: http://akka.io/docs/ >>>>>> >>>>>>>>>> Check the FAQ: http://akka.io/faq/ >>>>>> >>>>>>>>>> Search the archives: 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/84Mb4pEp4wQ/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/groups/opt_out. >>>>> >>>>> >>>>> -- >>>>> >>>>>>>>>> Read the docs: http://akka.io/docs/ >>>>> >>>>>>>>>> Check the FAQ: http://akka.io/faq/ >>>>> >>>>>>>>>> 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/groups/opt_out. >>>> >>>> >>>> >>>> >>>> Dr. Roland Kuhn >>>> Akka Tech Lead >>>> Typesafe – Reactive apps on the JVM. >>>> twitter: @rolandkuhn >>>> >>>> >>>> >>>> -- >>>> >>>>>>>>>> Read the docs: http://akka.io/docs/ >>>> >>>>>>>>>> Check the FAQ: http://akka.io/faq/ >>>> >>>>>>>>>> Search the archives: 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/84Mb4pEp4wQ/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/groups/opt_out. >>> >>> >>> -- >>> >>>>>>>>>> Read the docs: http://akka.io/docs/ >>> >>>>>>>>>> Check the FAQ: http://akka.io/faq/ >>> >>>>>>>>>> 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/groups/opt_out. >>> >>> >>> >>> -- >>> Cheers, >>> √ >>> >>> Viktor Klang >>> Director of Engineering >>> Typesafe >>> >>> Twitter: @viktorklang >>> >>> -- >>> >>>>>>>>>> Read the docs: http://akka.io/docs/ >>> >>>>>>>>>> Check the FAQ: http://akka.io/faq/ >>> >>>>>>>>>> Search the archives: 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/84Mb4pEp4wQ/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/groups/opt_out. >> >> >> -- >> >>>>>>>>>> Read the docs: http://akka.io/docs/ >> >>>>>>>>>> Check the FAQ: http://akka.io/faq/ >> >>>>>>>>>> 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/groups/opt_out. >> >> >> >> -- >> Cheers, >> √ >> >> Viktor Klang >> Director of Engineering >> Typesafe >> >> Twitter: @viktorklang >> >> -- >> >>>>>>>>>> Read the docs: http://akka.io/docs/ >> >>>>>>>>>> Check the FAQ: http://akka.io/faq/ >> >>>>>>>>>> Search the archives: 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/84Mb4pEp4wQ/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/groups/opt_out. > > > -- > >>>>>>>>>> Read the docs: http://akka.io/docs/ > >>>>>>>>>> Check the FAQ: http://akka.io/faq/ > >>>>>>>>>> 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/groups/opt_out. > > > > -- > > Patrik Nordwall > Typesafe - Reactive apps on the JVM > Twitter: @patriknw > > > > -- > >>>>>>>>>> Read the docs: http://akka.io/docs/ > >>>>>>>>>> Check the FAQ: http://akka.io/faq/ > >>>>>>>>>> Search the archives: 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/84Mb4pEp4wQ/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/groups/opt_out. -- >>>>>>>>>> Read the docs: http://akka.io/docs/ >>>>>>>>>> Check the FAQ: http://akka.io/faq/ >>>>>>>>>> Search the archives: https://groups.google.com/group/akka-user --- You received this message because you are subscribed to 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