EAI Patterns with Actor Model: Aggregator

The Recipient List example didn’t demonstrate how the PriceQuote replies are assimilated by the MountaineeringSuppliesOrderProcessor. To correlate PriceQuote replies to the original RequestForQuotation we need to use the unique rfqId that has been passed along with each message:

orderProcessor ! RequestForQuotation("123", ...)
...
recipient ! RequestPriceQuote(rfq.rfqId, ...)
...
sender ! PriceQuote(rpq.rfqId, ...)

The previous example from Recipient List is extended here to include an Aggregator, which tracks the fulfillment of all requested price quotes. First note the new message types:

case class PriceQuoteFulFilled(priceQuote: PriceQuote)

case class RequiredPriceQuotesForFulfillment(rfqId: String, quotesRequested: Int)

case class QuotationFulfillment(rfqId: String, quotesRequested: Int, priceQuotes: Seq[PriceQuote], requester: ActorRef)
. . .

The full text is now available as part of my book Reactive Enterprise with Actor Model on Safari Books Online.

Vaughn Vernon

Vaughn Vernon

Vaughn Vernon is a Software Ecologist, Architect, Modeler. Vaughn is a leading expert in Domain-Driven Design, and a champion of simplicity and reactive systems. He consults and teaches around Domain-Driven Design and reactive software development, helping teams and organizations realize the potential of business-driven and reactive systems as they transition from technology-driven legacy web implementation approaches. As he does so, he puts strong emphasis on embracing simplicity whenever possible. Vaughn is the author of four books: Implementing Domain-Driven Design, Domain-Driven Design Distilled, Strategic Monoliths and Microservices, and Reactive Messaging Patterns with the Actor Model, all published by Addison-Wesley.

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