Akka Concurrency

Description

Writing truly concurrent software on the Java Virtual Machine just got a whole lot easier. The Akka Toolkit takes the sting out of coding for multiple cores, multiple processors, and even multiple machines. Akka Concurrency will show you what it means to design and write software in the paradigm of Akka. You'll learn how to think about your software in new and exciting ways that will allow you to express your designs naturally, allowing you to focus on the business of your software more than on the concurrency of it. This book picks up where the Akka documentation leaves off, exploring the how and the why of Akka, in a way that will empower you to grow your applications to new levels of scalability, responsiveness, and performance. Contents......Page 7 List of Figures......Page 13 Introduction......Page 16 Why Akka?......Page 23 Concurrent challenges......Page 24 Concurrency methodologies......Page 26 The Akka concurrency toolkit......Page 28 So, why Akka?......Page 31 Parallelism versus concurrency......Page 32 A critical look at shared-state concurrency......Page 33 Immutability......Page 44 Conclusion......Page 56 Installation using the Typesafe stack......Page 57 That's it?......Page 59 The actor......Page 60 The future......Page 77 The other stuff......Page 83 You grabbed the right toolkit......Page 87 Actors......Page 88 The components of an actor......Page 90 Properties of an actor......Page 92 How to talk to an actor......Page 96 Creating actors......Page 100 Actors in the clouds......Page 101 Tying it together......Page 116 How message sending really works......Page 118 The ActorSystem runs the show......Page 122 Conclusion......Page 124 Making changes to sbt......Page 126 A bit of refactoring......Page 127 Testing the EventSource......Page 129 The interaction between ImplicitSender and testActor......Page 133 TestKit, ActorSystem, and ScalaTest......Page 134 Testing the altimeter......Page 139 Akka's other testing facilities......Page 146 About test probes and the testActor......Page 148 Chapter summary......Page 150 The ActorSystem......Page 151 Actor paths......Page 153 Staffing the plane......Page 155 The ActorContext......Page 165 Relating the path, context, and system......Page 172 Chapter summary......Page 174 What makes actors fail?......Page 176 The actor life cycle......Page 177 What is a supervisor?......Page 180 Watching for death......Page 188 The plane that healed itself......Page 194 Dead pilots......Page 216 Chapter summary......Page 223 Changing behaviour......Page 225 The stateful flight attendant......Page 230 A better flyer......Page 237 The naughty pilot......Page 258 Some challenges......Page 269 Testing FSMs......Page 270 Testing the pilot......Page 272 Chapter summary......Page 273 Akka's standard routers......Page 275 Routers and children......Page 282 Routers on a plane......Page 285 Magically appearing flight attendants......Page 298 Sectioning off flight attendant territory......Page 300 More you can do with routers......Page 304 Chapter summary......Page 305 Dispatchers......Page 307 Dispatcher tweaking......Page 311 Mailboxes......Page 313 When to choose a dispatching method......Page 320 Chapter summary......Page 321 What is the future?......Page 322 Don't wait for the future......Page 325 Promises and futures......Page 328 Functional futures......Page 330 Side-effecting......Page 349 Futures and actors......Page 354 Plane futures......Page 364 Chapter summary......Page 367 The plane's Telnet server......Page 369 Chapter summary......Page 377 Many actors, many stages......Page 379 Remote Airports......Page 380 Going remote......Page 386 Flying to the Airport......Page 390 Programmatic remote deployment......Page 398 Configured remote deployment......Page 401 Routers across multiple nodes......Page 403 Serialization......Page 404 Remote system events......Page 408 On the subject of lost messages......Page 411 Chapter summary......Page 412 Sharing Data with Agents......Page 414 Agents as counters......Page 415 Working with agents......Page 421 The API......Page 422 Chapter summary......Page 427 Caveats......Page 429 Getting dataflow into the build......Page 430 Flow......Page 431 Another way to get instrument status......Page 436 Chapter summary......Page 437 Behavioural composition......Page 438 Isolated and parallel testing......Page 442 Strategies for implementing request/response......Page 445 Mechanisms for handling non-deterministic bootstrapping......Page 453 The circuit breaker......Page 457 Breaking up a long-running algorithm into multiple steps......Page 458 Going parallel......Page 461 An actor EventBus......Page 462 Retry behaviour......Page 464 Shutting down when all actors complete......Page 465 Chapter Summary......Page 467 Mutability in messages......Page 469 Closing over actor data......Page 470 Violating the single-responsibility principle......Page 473 Inappropriate relationships......Page 474 Too much actorFor......Page 475 Not enough config......Page 477 Lots of ActorSystems......Page 478 Synchronizing the asynchronous......Page 479 Not reading the docs......Page 480 Chapter summary......Page 481 Extensions......Page 482 ZeroMQ......Page 484 Camel......Page 485 Clustering......Page 487 HTTP......Page 488 Monitoring......Page 489 Chapter summary......Page 490 Immutability......Page 491 akka.japi.Procedure......Page 492 Messages......Page 495 The untyped actor......Page 496 Futures......Page 501 Finite state machines......Page 507 Chapter summary......Page 508 akka.io......Page 509 Have fun!......Page 510 Bibliography......Page 511 About the author......Page 512 Index......Page 513