Learning RxJava - Build concurrent, maintainable , and responsive Java in less time.

Book Description RxJava is a library for composing asynchronous and event-based programs using Observable sequences for the JVM, allowing developers to build robust applications in less time. Learning RxJava addresses all the fundamentals of reactive programming to help readers write reactive code, as well as teach them an effective approach to designing and implementing reactive libraries and applications. Starting with a brief introduction to reactive programming concepts, there is an overview of Observables and Observers, the core components of RxJava, and how to combine different streams of data and events together. You will also learn simpler ways to achieve concurrency and remain highly performant, with no need for synchronization. Later on, we will leverage backpressure and other strategies to cope with rapidly-producing sources to prevent bottlenecks in your application. After covering custom operators, testing, and debugging, the book dives into hands-on examples using RxJava on Android as well as Kotlin. What You Will Learn Learn the features of RxJava 2 that bring about many significant changes, including new reactive types such as Flowable, Single, Maybe, and Completable Understand how reactive programming works and the mindset to "think reactively" Demystify the Observable and how it quickly expresses data and events as sequences Learn the various Rx operators that transform, filter, and combine data and event sequences Leverage multicasting to push data to multiple destinations, and cache and replay them Discover how concurrency and parallelization work in RxJava, and how it makes these traditionally complex tasks trivial to implement Apply RxJava and Retrolambda to the Android domain to create responsive Android apps with better user experiences Use RxJava with the Kotlin language to express RxJava more idiomatically with extension functions, data classes, and other Kotlin features Cover......Page 0 Credits......Page 4 About the Author......Page 5 Acknowledgements......Page 6 About the Reviewers......Page 8 www.PacktPub.com......Page 9 Customer Feedback......Page 10 Table of Contents......Page 11 Preface......Page 18 Chapter 1: Thinking Reactively......Page 24 A brief history of ReactiveX and RxJava......Page 25 Thinking reactively......Page 26 Why should I learn RxJava?......Page 27 Setting up......Page 28 Navigating the Central Repository......Page 29 Using Gradle......Page 30 Using Maven......Page 32 A quick exposure to RxJava......Page 33 When to use RxJava......Page 37 Summary......Page 38 How Observables work......Page 40 Using Observable.create()......Page 41 Using Observable.just()......Page 45 The Observer interface......Page 47 Implementing and subscribing to an Observer......Page 48 Shorthand Observers with lambdas......Page 49 Cold versus hot Observables......Page 51 Cold Observables......Page 52 Hot Observables......Page 55 ConnectableObservable......Page 57 Observable.range()......Page 59 Observable.interval()......Page 61 Observable.future()......Page 64 Observable.never()......Page 65 Observable.error()......Page 66 Observable.defer()......Page 67 Observable.fromCallable()......Page 70 Single......Page 71 Maybe......Page 72 Completable......Page 74 Disposing......Page 75 Handling a Disposable within an Observer......Page 76 Using CompositeDisposable......Page 78 Handling Disposal with Observable.create()......Page 79 Summary......Page 81 Suppressing operators......Page 82 take()......Page 83 skip()......Page 85 takeWhile() and skipWhile()......Page 86 distinct()......Page 87 distinctUntilChanged()......Page 89 elementAt()......Page 90 map()......Page 91 startWith()......Page 92 switchIfEmpty()......Page 94 sorted()......Page 95 delay()......Page 97 repeat()......Page 98 scan()......Page 99 count()......Page 101 reduce()......Page 102 all()......Page 103 contains()......Page 104 Collection operators......Page 105 toList()......Page 106 toMap() and toMultiMap()......Page 107 collect()......Page 110 Error recovery operators......Page 111 onErrorReturn() and onErrorReturnItem()......Page 112 onErrorResumeNext()......Page 114 retry()......Page 116 doOnNext(), doOnComplete(), and doOnError()......Page 118 doOnSubscribe() and doOnDispose()......Page 120 Summary......Page 122 Chapter 4: Combining Observables......Page 124 Observable.merge() and mergeWith()......Page 125 flatMap()......Page 129 Concatenation......Page 134 Observable.concat() and concatWith()......Page 135 concatMap()......Page 137 Ambiguous......Page 138 Zipping......Page 140 Combine latest......Page 142 withLatestFrom()......Page 144 Grouping......Page 145 Summary......Page 147 Chapter 5: Multicasting, Replaying, and Caching......Page 149 Understanding multicasting......Page 150 Multicasting with operators......Page 151 When to multicast......Page 156 Automatic connection......Page 158 autoConnect()......Page 159 refCount() and share()......Page 162 Replaying......Page 164 Caching......Page 169 PublishSubject......Page 170 When to use Subjects......Page 171 When Subjects go wrong......Page 173 Serializing Subjects......Page 174 BehaviorSubject......Page 175 ReplaySubject......Page 176 AsyncSubject......Page 177 UnicastSubject......Page 178 Summary......Page 181 Why concurrency is necessary......Page 182 Concurrency in a nutshell......Page 183 Introducing RxJava concurrency......Page 184 Keeping an application alive......Page 190 Understanding Schedulers......Page 193 New thread......Page 194 Trampoline......Page 195 ExecutorService......Page 196 Understanding subscribeOn()......Page 197 Nuances of subscribeOn()......Page 201 Understanding observeOn()......Page 204 Using observeOn() for UI event threads......Page 208 Nuances of observeOn()......Page 210 Parallelization......Page 211 unsubscribeOn()......Page 216 Summary......Page 219 Chapter 7: Switching, Throttling, Windowing, and Buffering......Page 220 Fixed-size buffering......Page 221 Time-based buffering......Page 224 Boundary-based buffering......Page 226 Fixed-size windowing......Page 227 Time-based windowing......Page 229 Boundary-based windowing......Page 230 Throttling......Page 231 throttleLast() / sample()......Page 233 throttleWithTimeout() / debounce()......Page 234 Switching......Page 236 Grouping keystrokes......Page 241 Summary......Page 244 Understanding backpressure......Page 245 An example that needs backpressure......Page 247 Introducing the Flowable......Page 249 Use an Observable If.........Page 251 Use a Flowable If.........Page 252 Understanding the Flowable and Subscriber......Page 253 The Subscriber......Page 254 Creating a Flowable......Page 259 Using Flowable.create() and BackpressureStrategy......Page 260 Turning an Observable into a Flowable (and vice-versa)......Page 262 onBackPressureBuffer()......Page 264 onBackPressureLatest()......Page 267 onBackPressureDrop()......Page 268 Using Flowable.generate()......Page 269 Summary......Page 273 Transformers......Page 274 ObservableTransformer......Page 275 FlowableTransformer......Page 279 Avoiding shared state with Transformers......Page 280 Using to() for fluent conversion......Page 283 Implementing an ObservableOperator......Page 286 FlowableOperator......Page 291 Custom Transformers and operators for Singles, Maybes, and Completables......Page 294 Using RxJava2-Extras and RxJava2Extensions......Page 295 Summary......Page 296 Chapter 10: Testing and Debugging......Page 298 Blocking subscribers......Page 299 Blocking operators......Page 302 blockingFirst()......Page 303 blockingGet()......Page 304 blockingLast()......Page 305 blockingIterable()......Page 306 blockingNext()......Page 307 blockingLatest()......Page 308 blockingMostRecent()......Page 309 Using TestObserver and TestSubscriber......Page 310 Manipulating time with the TestScheduler......Page 312 Debugging RxJava code......Page 314 Summary......Page 319 Chapter 11: RxJava on Android......Page 320 Creating the Android project......Page 321 Configuring Retrolambda......Page 327 Configuring RxJava and friends......Page 330 Using RxJava and RxAndroid......Page 331 Using RxBinding......Page 335 Other RxAndroid bindings libraries......Page 338 Life cycles and cautions using RxJava with Android......Page 339 Summary......Page 343 Chapter 12: Using RxJava for Kotlin New......Page 344 Configuring Kotlin......Page 345 Configuring Kotlin for Maven......Page 346 Kotlin basics......Page 348 Creating a Kotlin file......Page 349 Assigning properties and variables......Page 350 Extension functions......Page 351 Kotlin lambdas......Page 352 Extension operators......Page 354 Using RxKotlin......Page 356 Dealing with SAM ambiguity......Page 357 Using let()......Page 359 Using apply()......Page 361 Tuples and data classes......Page 362 Future of ReactiveX and Kotlin......Page 364 Summary......Page 365 Making a Runnable a lambda......Page 366 Making a Supplier a lambda......Page 368 Making a Consumer a lambda......Page 370 Making a Function a lambda......Page 372 Functional types......Page 374 Mixing object-oriented and reactive programming......Page 375 Materializing and Dematerializing......Page 380 Understanding Schedulers......Page 383 Index......Page 387 Reactive Programming with Java and ReactiveXAbout This BookExplore the essential tools and operators RxJava provides, and know which situations to use them inDelve into Observables and Subscribers, the core components of RxJava used for building scalable and performant reactive applicationsDelve into the practical implementation of tools to effectively take on complex tasks such as concurrency and backpressureWho This Book Is ForThe primary audience for this book is developers with at least a fundamental mastery of Java.Some readers will likely be interested in RxJava to make programs more resilient, concurrent, and scalable. Others may be checking out reactive programming just to see what it is all about, and to judge whether it can solve any problems they may have.What You Will LearnLearn the features of RxJava 2 that bring about many significant changes, including new reactive types such as Flowable, Single, Maybe, and CompletableUnderstand how reactive programming works and the mindset to'think reactively'Demystify the Observable and how it quickly expresses data and events as sequencesLearn the various Rx operators that transform, filter, and combine data and event sequencesLeverage multicasting to push data to multiple destinations, and cache and replay themDiscover how concurrency and parallelization work in RxJava, and how it makes these traditionally complex tasks trivial to implementApply RxJava and Retrolambda to the Android domain to create responsive Android apps with better user experiencesUse RxJava with the Kotlin language to express RxJava more idiomatically with extension functions, data classes, and other Kotlin featuresIn DetailRxJava is a library for composing asynchronous and event-based programs using Observable sequences for the JVM, allowing developers to build robust applications in less time.Learning RxJava addresses all the fundamentals of reactive programming to help readers write reactive code, as well as teach them an effective approach to designing and implementing reactive libraries and applications.Starting with a brief introduction to reactive programming concepts, there is an overview of Observables and Observers, the core components of RxJava, and how to combine different streams of data and events together. You will also learn simpler ways to achieve concurrency and remain highly performant, with no need for synchronization. Later on, we will leverage backpressure and other strategies to cope with rapidly-producing sources to prevent bottlenecks in your application. After covering custom operators, testing, and debugging, the book dives into hands-on examples using RxJava on Android as well as Kotlin.Style and approachThis book will be different from other Rx books, taking an approach that comprehensively covers Rx concepts and practical applications. Reactive Programming with Java and ReactiveX About This Book Explore the essential tools and operators RxJava provides, and know which situations to use them in Delve into Observables and Subscribers, the core components of RxJava used for building scalable and performant reactive applications Delve into the practical implementation of tools to effectively take on complex tasks such as concurrency and backpressure Who This Book Is For The primary audience for this book is developers with at least a fundamental mastery of Java. Some readers will likely be interested in RxJava to make programs more resilient, concurrent, and scalable. Others may be checking out reactive programming just to see what it is all about, and to judge whether it can solve any problems they may have. What You Will Learn Learn the features of RxJava 2 that bring about many significant changes, including new reactive types such as Flowable, Single, Maybe, and Completable Understand how reactive programming works and the mindset to "think reactively" Demystify the Observable and how it quickly expresses data and events as sequences Learn the various Rx operators that transform, filter, and combine data and event sequences Leverage multicasting to push data to multiple destinations, and cache and replay them Discover how concurrency and parallelization work in RxJava, and how it makes these traditionally complex tasks trivial to implement Apply RxJava and Retrolambda to the Android domain to create responsive Android apps with better user experiences Use RxJava with the Kotlin language to express RxJava more idiomatically with extension functions, data classes, and other Kotlin features In Detail RxJava is a library for composing asynchronous and event-based programs using Observable sequences for the JVM, allowing developers to build robust applications in less time. Learning RxJava addresses all the fundamentals of reactive programming to help readers write reactive code, as well as teach them an effective approach to designing and implementing reactive libraries and applications. Starting with a brief introduction to reactive programming concepts, there is an overview of Observables and Observers, the core components of RxJava, and how to combine different streams of data and events together. You will also learn simpler ways to achieve concurrency and remain highly performant, with no need for synchronization. Later on, we will leverage backpressure and other strategies ..