Reactive 4TW

Reactive programming is a new big thing for a couple of years now, but it also shrouded with a distrust as any new technology with mindblowing concepts. Lets pretend together that you didn't hear about Reactive and start learning it from scratch!

Transcript

1. Introduction to Reactive principles with RxJava
   @AlexeyBuzdin
   Reactive 4TW!
   

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2. @AlexeyBuzdin
   Developer / Trainer at
   

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3. this page was
   intentionally left blank…
   Reactive
   

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5. Good?
   

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6. or Bad?
   

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7. Scary
   

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8. but Productive!
   

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9. reactive /rɪˈaktɪv/
   1. showing a response to a stimulus.
   "pupils are reactive to light"
   2. acting in response to a situation rather than
   creating or controlling it.
   "a proactive rather than a reactive approach"
   

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10. reactive /rɪˈaktɪv/
    1. showing a response to a stimulus.
    "pupils are reactive to light"
    2. acting in response to a situation rather than
    creating or controlling it.
    "a proactive rather than a reactive approach"
    

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12. Observer
    Observable
    Object
    

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13. Observer
    Observable
    Object
    

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14. Observer
    Observable
    Object
    

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15. Observer
    Observable
    Object
    

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16. Observable
    

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17. Observer
    

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18. Object(Event)
    

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19. programming with asynchronous data streams
    Reactive programming is
    

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20. List balls = Collections.singletonList(new Ball());
    Observable pitcher = Observable.from(balls);
    Observer batter = new Observer() {
    @Override
    public void onCompleted() { /* Score! */ }
    @Override
    public void onError(Throwable e) { /* Shame */ }
    @Override
    public void onNext(Ball ball) { /* Hit! */ }
    };
    pitcher.subscribe(batter);
    

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21. List balls = Collections.singletonList(new Ball());
    Observable pitcher = Observable.from(balls);
    Observer batter = new Observer() {
    @Override
    public void onCompleted() { /* Score! */ }
    @Override
    public void onError(Throwable e) { /* Shame */ }
    @Override
    public void onNext(Ball ball) { /* Hit! */ }
    };
    pitcher.subscribe(batter);
    

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22. List balls = Collections.singletonList(new Ball());
    Observable pitcher = Observable.from(balls);
    Observer batter = new Observer() {
    @Override
    public void onCompleted() { /* Score! */ }
    @Override
    public void onError(Throwable e) { /* Shame */ }
    @Override
    public void onNext(Ball ball) { /* Hit! */ }
    };
    pitcher.subscribe(batter);
    

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23. List balls = Collections.singletonList(new Ball());
    Observable pitcher = Observable.from(balls);
    Observer batter = new Observer() {
    @Override
    public void onCompleted() { /* Score! */ }
    @Override
    public void onError(Throwable e) { /* Shame */ }
    @Override
    public void onNext(Ball ball) { /* Hit! */ }
    };
    pitcher.subscribe(batter);
    

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24. List balls = /* Infinite balls */
    Observable pitcher = Observable.from(balls);
    Observer batter = new Observer() {
    @Override
    public void onCompleted() { /* Score! */ }
    @Override
    public void onError(Throwable e) { /* Shame */ }
    @Override
    public void onNext(Ball ball) { /* Hit! */ }
    };
    pitcher.subscribe(batter);
    

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25. programming with asynchronous data streams
    Reactive programming is
    

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27. Everything can be a Stream:
    - collections
    - user inputs
    - hardware
    - properties
    - caches
    - data structures
    - etc.
    

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28. Collections
    List< > balls = Lists.emptyList();
    

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29. Everything can be a Stream:
    - collections
    - user inputs
    - hardware
    - properties
    - caches
    - data structures
    - etc.
    

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30. UserInput
    Button btw = new Button(ctx);
    btn.setOnClickListener(e -> {
    // Do something
    })
    

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31. Everything can be a Stream:
    - collections
    - user inputs
    - hardware
    - properties
    - caches
    - data structures
    - etc.
    

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32. Hardware
    LocationManager mng = (LocationManager)
    getSystemService(Context.LOCATION_SERVICE);
    LocationListener listener = new LocationListener() {
    public void onLocationChanged(Location location) {
    // Do something
    }
    …..
    };
    locationManager.requestLocationUpdates
    (LocationManager.NETWORK_PROVIDER, 0, 0, listener);
    

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33. Everything can be a Stream:
    - collections
    - user inputs
    - hardware
    - properties
    - caches
    - data structures
    - etc.
    

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34. UserInput
    SharedPreferences prefs =
    PreferenceManager.getDefaultSharedPreferences(this);
    prefs.getBoolean("keystring", true);
    

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35. Everything can be a Stream:
    - collections
    - user inputs
    - hardware
    - properties
    - caches
    - data structures
    - etc.
    

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36. DataBase
    select().from(t).where(row(t.a, t.b).eq(1, 2));
    

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37. Everything can be a Stream:
    - collections
    - user inputs
    - hardware
    - properties
    - caches
    - data structures
    - etc.
    

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38. Data Structures
    

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39. Everything can be a Stream:
    - collections
    - user inputs
    - hardware
    - properties
    - caches
    - data structures
    - etc.
    

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40. …and what next?
    

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41. Operations!
    

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42. Operations!
    - map
    - filter
    - zip
    - groupBy
    - collect
    - flatMap
    - etc.
    

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43. RealLife RX
    RxView.clickEvents(tapBtn)
    .map(new Func1() {
    @Override
    public Integer call(ViewClickEvent onClickEvent) {
    log("GOT A TAP");
    return 1;
    }
    })
    .buffer(2, TimeUnit.SECONDS)
    .observeOn(AndroidSchedulers.mainThread())
    .subscribe( /* Observer here */)
    

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44. programming with asynchronous data streams
    Reactive programming is
    

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46. programming with asynchronous data streams
    Reactive programming is
    

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47. RealLife RX
    

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50. Try it Out!
    

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51. Q&A
    

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