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
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>>>>
>>>>
>>>> --
>>>> >>>>>>>>>> Read the docs: http://akka.io/docs/
>>>> >>>>>>>>>> Check the FAQ: http://akka.io/faq/
>>>> >>>>>>>>>> Search the archives: https://groups.google.com/
>>>> group/akka-user
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>>>>
>>>>
>>>>
>>>> *Dr. Roland Kuhn*
>>>> *Akka Tech Lead*
>>>> Typesafe <http://typesafe.com/> – Reactive apps on the JVM.
>>>> twitter: @rolandkuhn
>>>> <http://twitter.com/#!/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
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>>>>
>>>>
>>>> --
>>>> >>>>>>>>>> Read the docs: http://akka.io/docs/
>>>> >>>>>>>>>> Check the FAQ: http://akka.io/faq/
>>>> >>>>>>>>>> Search the archives: https://groups.google.com/
>>>> group/akka-user
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>>>
>>>
>>>
>>> --
>>> Cheers,
>>> √
>>>
>>> * Viktor Klang*
>>> *Director of Engineering*
>>> Typesafe <http://www.typesafe.com/>
>>>
>>> Twitter: @viktorklang
>>>
>>> --
>>> >>>>>>>>>> Read the docs: http://akka.io/docs/
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>>> --
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>>
>>
>>
>> --
>> Cheers,
>> √
>>
>> * Viktor Klang*
>> *Director of Engineering*
>> Typesafe <http://www.typesafe.com/>
>>
>> Twitter: @viktorklang
>>
>> --
>> >>>>>>>>>> Read the docs: http://akka.io/docs/
>> >>>>>>>>>> Check the FAQ: http://akka.io/faq/
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>>
>> --
> >>>>>>>>>> Read the docs: http://akka.io/docs/
> >>>>>>>>>> Check the FAQ: http://akka.io/faq/
> >>>>>>>>>> Search the archives: https://groups.google.com/group/akka-user
> ---
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--
Patrik Nordwall
Typesafe <http://typesafe.com/> - 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
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