Function composition
Functors, applicative functors, and monads
The Scalaz dependency
Functor
Applicative functor
Revisiting point and pure
Monad
Indexing files for searching
Function composition revisited
Ease of unit testing
Summary
3. Asynchronous Programming in Scala
Synchronous versus asynchronous programming
Synchronous programming
Asynchronous programming
Futures
Futures as concurrency abstraction
Futures in Scala
How Futures in Scala work
Writing your first Future in Scala
Understanding Futures in Scala
Enter Promise
Composing Futures
Why nested Futures are hard
Building an asynchronous client
Implementing the service
Implementing a client API for CoffeeShop
Query for ShopMenu
Placing an order with CoffeeShop
Canceling an order
Confirming an order
Paying for an order
Example – A simple data crawler using Futures
About the dataset
Structure of the dataset
Goal
A sample RSS XML file
Data crawler workflow
Implementation
RSSReader
Page crawler
Wiring up and moving forward
Summary
4. Akka for Reactive Programming
Concurrency and parallelism
Actor model
Threads and actors
An introduction to Akka
Actor mailbox
Actor systems
Messaging passing
Creating an actor system
Creating an ActorRef
Sending a PizzaRequest to the ActorRef
Actor messages
Mailbox
Dispatcher
Actor path
The actor life cycle
Deadletters
Event streams
Actor deathwatch
Actor supervision
Supervision strategies
OneForOneStrategy
The actor hierarchy
PastaException
The final state
AllForOneStrategy
The actor hierarchy
PastaException
The final state
Summary
5. Building Resilient Application with Akka
An introduction to actor routing
Routers and routees
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