Think about what you are asking with when(_). Even if it did work it would
simply make all other when(..) irrelevant in the context of state
transitions within such FSM actor.
Now to some of your other points.
> ManagerFSM to create the child as long as the actor is preStarted
So, why not just override the preStart() method of an actor who is going to
be responsible for a child?
var childActor
override def preStart() {
childActor = context.actorOf(...)
}
or simply create a childActor during the construction of the parent actor
thus avoiding vars.
Having said that. . .
What is the purpose of the ManagerFSM and why do you believe it has to
manage someone else's children? IMHO its counterintuitive - children should
be managed by their parents otherwise they are not children. . . just
regular Actors;). (goes along with what Roland stated earlier)
Perhaps you could actually try to explain what exactly you are trying to
accomplish as a business use case since it seems like you may be making
things (architecture and design) more complex then they have to be.
Cheers
Oleg
On Wed, Feb 12, 2014 at 6:39 AM, Nader Aeinehchi <[email protected]>wrote:
> Hi Roland
>
> "sounds fishy, because actors do not expose methods, they only communicate
> via message passing"
> Agree. That is why I brought up this question.
>
> Let me try with an example:
>
> trait WorkerFSM[S, D] extends FSM[S, D]
> case class MyType // which can have subclasses to define different types
>
>
> trait ManagerFSM[S, D] extends FSM[S, D] {
>
> // here, "_" implies any state as long the actor is started and not stopped
> when(_){
> case(Event(MyType, _)){
> val myactor = context.actorOf[WorkerFSM[S,D]]("some name")
> sender ! myactor
> }}}
>
> The code above does not compile as I wrote in GMAIL.
>
> My problem is how to define "_" state as a wild card for all the states in
> the state machine.
>
> Thanks
> Nader
>
>
> On Wednesday, February 12, 2014 10:48:33 AM UTC+1, rkuhn wrote:
>
>> Hi Nader,
>>
>> I think it would be best if you demonstrated your problem with code; the
>> pseudo-code in the first email did not help me in this regard it seems.
>>
>> Just one thing: <<The manager class (ManagerFSM) exposes a method>> sounds
>> fishy, because actors do not expose methods, they only communicate via
>> message passing. The only thing you will see from the outside is the
>> ActorRef, which supports nothing besides the `tell` operation (which `ask`
>> is a variant of).
>>
>> Regards,
>>
>> Roland
>>
>> 12 feb 2014 kl. 09:08 skrev Nader Aeinehchi <[email protected]>:
>>
>> Hi again
>>
>> Let me explain it better. There are two options:
>>
>> 1. The manager class (ManagerFSM) exposes a method. Within the method,
>> we call context.actorOf(....). But such method is part of the actor and
>> NOT ActorRef. I do not know how to access such method from a client code.
>> Perhaps, I misunderstand something here?
>> 2. The second alternative is based on passing a Message to ManagerFSM.
>> Here, I struggle with FSM state handling mechanism. I cannot see an option
>> that sound "when(_){context.actorOf{...}".
>>
>> Perhaps, I misunderstand something here?
>>
>> In advance thank you very much.
>>
>> Best regards
>> Nader
>>
>>
>> On Tuesday, February 11, 2014 1:07:27 PM UTC+1, Akka Team wrote:
>>
>>> Hi Nader,
>>>
>>> it is not completely clear to me what you mean, especially by the "Does
>>> not work" comment. Within an FSM you can create child actors just like in
>>> any other actor, using "context.actorOf(...<props>..., name)". Child actors
>>> enjoy the same kind of encapsulation from all others--including from their
>>> parent--so you will need to send messages to communicate with them.
>>>
>>> Regards,
>>>
>>> Roland
>>>
>>>
>>>
>>> On Mon, Feb 10, 2014 at 10:24 PM, Nader Aeinehchi
>>> <[email protected]>wrote:
>>>
>>>> Hi
>>>>
>>>> How can a child actor (which itself implements FSM) be created and
>>>> added as a child to the context of a FSM actor?
>>>>
>>>> Suppose the following pseudocode:
>>>>
>>>> trait WorkerFSM[S, D] extends FSM[S, D]
>>>>
>>>> trait ManagerFSM[S, D] extends FSM[S, D] {
>>>>
>>>> // Does not work
>>>> // Create some WorkerFSM actor and add it to the children of this
>>>> ManagerFSM
>>>> def actorOf[w <: WorkerFSM[S, D]](name: String): FSM[S, D]
>>>> }
>>>>
>>>> The above does not work as only the reference to ActorRed is available
>>>> to the client code. In other words, the client code cannot access the
>>>> method "actorOf".
>>>>
>>>> One other alternative is to send messages to ManagerFSM. The problem
>>>> is that FSM is coupled to the given state using the construct
>>>> when(someState). But here, we would like ManagerFSM to create the child as
>>>> long as the actor is preStarted and not stopped (as dictated by Actor's
>>>> state diagram and not the fine-grained FSM state diagram).
>>>>
>>>> Any ideas?
>>>>
>>>> In advance, thank you very much.
>>>>
>>>> Nader
>>>>
>>>> --
>>>> >>>>>>>>>> Read the docs: http://akka.io/docs/
>>>> >>>>>>>>>> Check the FAQ: http://akka.io/faq/
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>>>
>>>
>>>
>>> --
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>>>
>>
>> --
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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/
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