Andrea Maglie Reactive Java Programming Andrea Maglie Venice, Italy ISBN-13 (pbk): 978-1-4842-1429-9 ISBN-13 (electronic): 978-1-4842-1428-2 DOI 10.1007/978-1-4842-1428-2 Library of Congress Control Number: 2016957883 Copyright 2016 by Andrea Maglie This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. Trademarked names, logos, and images may appear in this book. Rather than use a trademark symbol with every occurrence of a trademarked name, logo, or image we use the names, logos, and images only in an editorial fashion and to the benefit of the trademark owner, with no intention of infringement of the trademark. The use in this publication of trade names, trademarks, service marks, and similar terms, even if they are not identified as such, is not to be taken as an expression of opinion as to whether or not they are subject to proprietary rights. While the advice and information in this book are believed to be true and accurate at the date of publication, neither the authors nor the editors nor the publisher can accept any legal responsibility for any errors or omissions that may be made.
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About the Author .............................................................................. xi About the Technical Reviewer ........................................................ xiii Acknowledgments ........................................................................... xv Introduction ................................................................................... xvii Chapter 1: ReactiveX and RxJava ................................................... 11 Chapter 3: Subscription Lifecycle ................................................. 41 Chapter 4: Subjects ...................................................................... 61 Chapter 5: Networking with RxJava and Retro t ......................... 79 Chapter 6: RxJava and Android .................................................... 95 Index .............................................................................................. 107
About the Author .............................................................................. xi About the Technical Reviewer ........................................................ xiii Acknowledgments ........................................................................... xv Introduction ................................................................................... xvii Chapter 1: ReactiveX and RxJava ................................................... 1 Introduction ............................................................................................. 1 Imperative and Functional Programming ................................................ 1 Lambda Expressions ................................................................................................. 3 Imperative or Functional? ......................................................................................... 4 Reactive Programming ............................................................................ 4 Streams of Data ...................................................................................... 5 The Observer Pattern .............................................................................. 5 Whats ReactiveX? ................................................................................... 6 Whats RxJava? ....................................................................................... 7 Chapter 2: Observables and Observers ........................................ 11 Introduction ........................................................................................... 11 Adding RxJava to Your Project ............................................................... 11 De nition of Observable ........................................................................ 12 De nition of Observer ........................................................................... 12 onNext, onCompleted, onError............................................................... 13 Hot and Cold Observables ..................................................................... 15 CONTENTS Creating Observables ............................................................................ 16 Observable.just() ..................................................................................................... 16 Observable.range() ................................................................................................. 17 Observable.interval() ............................................................................................... 17 Observable.timer() .................................................................................................. 18 Observable.create()................................................................................................. 18 Observable.empty() ................................................................................................. 19 Observable.error() ................................................................................................... 19 Observable.never() .................................................................................................. 19 Observable.defer() .................................................................................................. 20 Composing and Transforming Observables ........................................... 22 map......................................................................................................................... 22 atMap ................................................................................................................... 24 concatMap .............................................................................................................. 25 zip ........................................................................................................................... 26 concat ..................................................................................................................... 27 lter ........................................................................................................................ 29 distinct .................................................................................................................... 30 rst ......................................................................................................................... 30 last .......................................................................................................................... 31 take ......................................................................................................................... 33 startWith ................................................................................................................. 34 scan ........................................................................................................................ 35 Other Operators ...................................................................................................... 36 CONTENTS Chapter 3: Subscription Lifecycle ................................................. 41 Introduction ........................................................................................... 41 Error Handling ....................................................................................... 41 Handling Errors in the onError() Method ................................................................. 42 Ignoring the Exception and Continuing with Item Emission ................................... 43 Retry ....................................................................................................................... 46 Schedulers ............................................................................................ 49 Transformers .......................................................................................................... 53 Advanced Use of Schedulers .................................................................................. 54 Backpressure ........................................................................................ 55 Handling Backpressure During Emission: Throttling .............................................. 55 Handling Backpressure During Emission: Buffering ............................................... 57 Handling Backpressure Inside the Subscriber ........................................................ 59 Chapter 4: Subjects ...................................................................... 61 PublishSubject ...................................................................................... 63 BehaviorSubject .................................................................................... 66 ReplaySubject ....................................................................................... 69 AsyncSubject ......................................................................................... 70 When Should You Use Subjects? ........................................................... 72 Connectable Observables ...................................................................... 76 Chapter 5: Networking with RxJava and Retro t ......................... 79 Retro ts Built-in Support for RxJava .................................................... 80 Setting Up Retro t in Your Java Project .................................................................. 80 Creating a Retro t Service ..................................................................................... 80 Filter Results ........................................................................................................... 85 Choosing the Right Scheduler ............................................................... 87 CONTENTS Chaining Multiple Network Calls ........................................................... 88 Caching Data ......................................................................................... 90 Chapter 6: RxJava and Android .................................................... 95 RxAndroid .............................................................................................. 95 RxBindings ............................................................................................ 97 Activity and Fragment Life Cycle ......................................................... 101 Index .............................................................................................. 107
