Building a reactive mindset

@FMuntenescu

Florina Muntenescu@FMuntenescu

Building a Reactive Mindset

@FMuntenescu

Donald

Duck’s Burger

Joint

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Huey Dewey Louie

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Huey

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Dewey

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Louie

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Huey

Dewey

Louie

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filter(meat -> isMeatFresh(meat))

map(meat -> cook(meat))

Dewey

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zip

@FMuntenescuSTREAMS OF DATA

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zip

STREAMS OF DATA

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Consumer

Observable

Subscriber

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operators

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Huey.getBun()

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for(Meat meat: meatList){

if(!isMeatFresh(meat)){

meatList.remove(meat);

}

}

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Observable.from(meatSource)

.filter(meat ->

isMeatFresh(meat))


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for(Meat meat: meatList){

meat = cook(meat);

}

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Observable.from(meatSource)

.filter(meat ->

isMeatGoneBad(meat))

.map(meat -> cook(meat));



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Observable<Burger> burgerObservable =

Observable.zip(bunObservable,

meatObservable,

tomatoObservable,

(bun, meat, tomato) ->

makeBurger(bun, meat, tomato))

bunObservable

meatObservable

tomatoObservable

burgerObservable

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Observable

Subscriber

.subscribe

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Subscriber

burgerObservable

.subscribe(mickeySubscriber);

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Subscriber

onNext(Burger burger)

onCompleted()

burgerObservable

.subscribe(

burger -> eatBurger(burger),

error -> complain(error),

() -> leaveBurgerJoint());

// onNext

//onError

//onCompleted

onError(Throwable error)

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meatObservable,

tomatoObservable,



.subscribe(burger -> eatBurger(burger),

error -> complain(error));

// dining area

// dining area

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// kitchen


meatObservable,

tomatoObservable,





// dining area

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// kitchen

// dining area


meatObservable,

tomatoObservable,



.subscribeOn(kitchen)

.observeOn(dining area)



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meatObservable,

tomatoObservable,



.subscribeOn(Schedulers.computation())

.observeOn(AndroidSchedulers.mainThread())



// kitchen

// dining area

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Stream of data

ObservableSubscriber

OperatorsThreads

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Creating

Observables

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Creating

Observables

From a

List

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List<Burger> burgers = new ArrayList<>();

burgers.add(new Burger());



Observable.from(burgers);

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1 2

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burgerObservable.subscribe(new Subscriber<Burger>() {

@Override

public void onNext(final Burger burger) {

}

@Override

public void onCompleted() {

}

@Override

public void onError(final Throwable e) {

}

});

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Observable<Burger> burgerObservable = Observable.from(burgers);


@Override


// handle burger 1

}@Override


}

@Override


}

});

1

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@Override


// handle burger 2

}@Override


}

@Override


}

});

1 2

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@Override


}

@Override


// no more burgers!

}@Override


}

});

1 2

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Observable<List<Burger>>




burgerObservable =

Observable.just(burgers);

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1

Observable<List<Burger>> burgerObservable

=





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Observable<List<Burger>> burgerObservable =


burgerObservable.subscribe(

new Subscriber<List<Burger>>() {

@Override

public void onNext(final List<Burger> burgers) {

}

@Override


}

@Override


}

});

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@Override

public void onNext(

final List<Burger> burgers) {

// handle the list of burgers

} @Override


}

@Override


}

});

1

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@Override

public void onNext(

final List<Burger> burgers) {

// handle the list of burgers

}

@Override


// no more burgers!

}@Override


}

});

1

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Creating

Observables

From

Click

Events

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[click!] [click!] [click!]

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???.subscribe(new Subscriber<String>() {

@Override

public void onNext(final String s) {

// called on every click

}

@Override


}

@Override


}

});

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[click!] [click!] [click!]

???.onNext(…) ???.onNext(…) ???.onNext(…)

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burgerButton.setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(final View view) {

}

});

PublishSubject<String> burgerRequestedSubject =

PublishSubject.create();

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burgerButton.setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(final View view) {

burgerRequestedSubject.onNext(…);}

});

PublishSubject<String> burgerRequestedSubject =

PublishSubject.create();

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burgerRequestedSubject.subscribe(new Subscriber<String>() {

@Override

public void onNext(final String s) {

// called on every click

}

@Override


// will never be called for click events

}

@Override


}

});

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Creating

Observables

From

Declarativ

e Code

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public Burger cook(){

// cooking is time consuming

return burger;

}

Observable<Burger> burgerObservable = Observable.fromCallable(this::cook);

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Error

Handling

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Thread t = new Thread(new Runnable() {

@Override

public void run() {

cook();

}

});

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Thread t = new Thread(new Runnable() {

@Override

public void run() {

try{

cook();

} catch(Exception e) {

// handle exception

}

}

});

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getMeatObservable()

.filter(meat -> isMeatFresh(meat))

.map(meat -> cook(meat))

.subscribeOn(

meat -> doSomething(),


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public Observable<Meat> getCookedMeat() {

return getMeatObservable()


.map(meat -> cook(meat));

}

Observable.zip(getBun(),

getCookedMeat(),

getTomatoSlice(),



.subscribeOn(



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public Observable<Meat> getCookedMeat() {

return getMeatObservable()


.map(meat -> cook(meat));}

Observable.zip(getBun(),

getCookedMeat(),

getTomatoSlice(),



.subscribeOn(



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Start using

RxJava

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public Burger cook(){

// cooking is time consuming

// make sure it’s on a background thread

return burger;

}


Observable.fromCallable(this::cook)

.subscribeOn(Schedulers.computation())

.observeOn(AndroidSchedulers.mainThread())

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@GET(“repos”)

Call<List<Burger>> repoBurgers();

@GET(“repos”)

Observable<List<Burger>> repoBurgers();

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@FMuntenescu@FMuntenescu

[email protected]

Building a Reactive Mindset

https://upday.github.io/blog/reactive_mindset_burgers

Reactive Burgers – Code Example

https://github.com/florina-muntenescu/ReactiveBurgers

Building a BurgerReactive Mindset

Building a reactive mindset

Software

Transcript of Building a reactive mindset