I want to extract string from API response and assign that to a object. When print that value it will display but couldn't assign to a object. Please check below sample code base.
List<DtvPrePacksDataResponse> dtvPrePacksDataResponses =
channelGroupByGenre.entrySet().stream()
.map(e -> {
DtvPrePacksDataResponse dtvPrePacksDataResponse = new DtvPrePacksDataResponse();
dtvPrePacksDataResponse.setCatId(counter.incrementAndGet());
dtvPrePacksDataResponse.setCategoryName(e.getKey());
dtvPrePacksDataResponse.setChannelCount(e.getValue().size());
String channelCat = e.getValue().get(0).getProductCategoryId();
String channelSubcat = e.getValue().get(0).getProductSubCategoryId();
this.getChannelCatIcon(channelCat, channelSubcat)
.subscribe(
s -> this.catIconSet(dtvPrePacksDataResponse, s)
//s -> dtvPrePacksDataResponse.setCategoryIcon(s)
/*value -> System.out.println(value),
error -> error.printStackTrace(),
() -> System.out.println("completed without a value")*/
);
return dtvPrePacksDataResponse;
}).collect(Collectors.toList());
Retrive image from API response
private Mono<String> getChannelCatIcon(String channelCat, String channelSubcat) {
return productSubcategoryQueryClientInterface.getProductSubcategoryInfo(
channelCat,
channelSubcat
)
.collectList()
.map(productSubcategories -> {
ProductSubcategory productSubcategory = productSubcategories.stream()
.filter(productSubcategory1 -> productSubcategory1.getProductCategoryId().equals(channelCat) && productSubcategory1.getProductSubCategoryId().equals(channelSubcat))
.findFirst()
.orElseThrow(() -> new RuntimeException(INVALID_LANGUAGE_OBJECT));
ListSubcategoryUrl listSubcategoryUrl = productSubcategory.getListSubcategoryUrl().stream()
.filter(listSubcategoryUrl1 -> listSubcategoryUrl1.getProductUrlCode().equals("SUBCATEGORY_IMAGE") && listSubcategoryUrl1.getType().equals("IMAGE"))
.findFirst()
.orElseThrow(() -> new RuntimeException(INVALID_LANGUAGE_OBJECT));
return listSubcategoryUrl.getUrl();
}).cache();
}
Set Image to the object
private void catIconSet(DtvPrePacksDataResponse dtvPrePacksDataResponse, String url){
System.out.println("img url " + url);
dtvPrePacksDataResponse.setCategoryIcon(url);
}
Entity class
public class DtvPrePacksDataResponse {
private int catId;
private String categoryName;
private String categoryIcon;
private int channelCount;
private List<DtvPrePacksDataListResponse> channelList;
}
Using block() gives a error. Tried using flatmap() also gives error. Checked below question also and tried but no success
How to get String from Mono<String> in reactive java
How to extract string from Mono<String> in reactor core
I have this function inside a #Service in Spring Webflux and it is called with a list of friends to know if everyone has been joined to a group. If some friends have no group this method calls an API to get its user's information and then calls another API to tag these guys with joined tag false.
#Service
...
public Flux<Boolean> checkUserHaveGroup(final List<String> friends) {
MatchOperation match1 = Aggregation.match(Criteria.where("friends").in(friends).and("status").is("ACTIVE"));
UnwindOperation unwind1 = Aggregation.unwind("friends");
MatchOperation match2 = Aggregation.match(Criteria.where("friends").in(friends));
GroupOperation group1 = Aggregation.group("friends");
TypedAggregation<Group> a = Aggregation.newAggregation(
Group.class,
match1, unwind1, match2, group1);
return this.reactiveMongoTemplate.aggregate(a, FriendInGroup.class)
.map(friendInGroup -> friendInGroup.id)
.collectList()
.map(users -> haveNoGroupsList(users, friends))
.flatMapMany(noGroupUsers -> {
return Flux.fromIterable(noGroupUsers)
.flatMap(pn -> crmService.deleteAttribute(pn, "joinedAGroup"));
});
}
(this method get the user information)
...
public Mono<UserInfo> userInfoById(final String userId) {
return webClient.get()
.uri(uriBuilder -> uriBuilder.path(constants.getByIdPath() + "/{id}")
.build(userId))
.header("auth", tokenService.token())
.exchange()
.flatMap(response -> {
Mono<UserInfo> responseMono;
if (response.statusCode().equals(HttpStatus.UNAUTHORIZED)) {
responseMono = Mono.error(new UnauthorizedException());
} else if (response.statusCode().equals(HttpStatus.OK)) {
responseMono = response.bodyToMono(UserInfoResponse.class)
.flatMap(uir -> Mono.just(uir.getData()));
} else {
responseMono = Mono.error(new UnhandledException());
}
return responseMono;
});
}
...
private Mono<UserInfo> getUserInfo(String userId) {
return userInfoAdapter.userInfoById(userId);
}
...
public Mono<Boolean> deleteAttribute(final String userId, final String attribute) {
return getUserInfo(userId) <<<<< here we get the users info
.flatMap(ui -> crmDeleteAttribute(ui, attribute)); <<<< this call is never done.
}
...
public Mono<Boolean> crmDeleteAttribute(final UserInfo user, final String attribute) {
return webClient.delete()
.uri(uriBuilder -> uriBuilder
.path(contants.path())
.build(user.getId(), attribute))
.header("auth", tokenService.token())
.exchange().flatMap(response -> {
if (response.statusCode().equals(HttpStatus.OK)) {
return Mono.just(Boolean.TRUE);
}
if (response.statusCode().equals(HttpStatus.BAD_REQUEST)) {
return Mono.error(CrmServiceBadRequestException::new);
}
if (response.statusCode().equals(HttpStatus.UNAUTHORIZED)) {
return Mono.error(CrmServiceUnauthorizedException::new);
}
return Mono.error(CrmServiceUnhandledException::new);
});
}
After getting the users' info on the API, the API for assign a tag is never been called no matter what I do. I can see in the debugger terminal that the call to UserInfo API was done but after that, the application returns to the controller. Someone could point me to what I'm doing wrong?
Any help is welcome.
Thanks!
I've been tinkering with wrapping an old style listener interface using RxJava. What i've come up with seems to work, but the usage of Observable.using feels a bit awkward.
The requirements are:
Only one subscription per id to the underlying service.
The latest value for a given id should be cached and served to new subscribers.
We must unsubscribe from the underlying service if nothing is listening to an id.
Is there a better way? The following is what I've got.
static class MockServiceRXAdapterImpl1 implements MockServiceRXAdapter {
PublishSubject<MockResponse> mockResponseObservable = PublishSubject.create();
MockService mockService = new MockService(mockResponse -> mockResponseObservable.onNext(mockResponse));
final ConcurrentMap<String, Observable<String>> subscriptionMap = new ConcurrentHashMap<>();
public Observable<String> getObservable(String id) {
return Observable.using(() -> subscriptionMap.computeIfAbsent(
id,
key -> mockResponseObservable.filter(mockResponse -> mockResponse.id.equals(id))
.doOnSubscribe(disposable -> mockService.subscribe(id))
.doOnDispose(() -> {
mockService.unsubscribe(id);
subscriptionMap.remove(id);
})
.map(mockResponse -> mockResponse.value)
.replay(1)
.refCount()),
observable -> observable,
observable -> {
}
);
}
}
You may use Observable.create
So code may look like this
final Map<String, Observable<String>> subscriptionMap = new HashMap<>();
MockService mockService = new MockService();
public Observable<String> getObservable(String id) {
log.info("looking for root observable");
if (subscriptionMap.containsKey(id)) {
log.info("found root observable");
return subscriptionMap.get(id);
} else {
synchronized (subscriptionMap) {
if (!subscriptionMap.containsKey(id)) {
log.info("creating new root observable");
final Observable<String> responseObservable = Observable.create(emitter -> {
MockServiceListener listener = emitter::onNext;
mockService.addListener(listener);
emitter.setCancellable(() -> {
mockServices.removeListener(listener);
mockService.unsubscribe(id);
synchronized (subscriptionMap) {
subscriptionMap.remove(id);
}
});
mockService.subscribe(id);
})
.filter(mockResponse -> mockResponse.id.equals(id))
.map(mockResponse -> mockResponse.value)
.replay(1)
.refCount();
subscriptionMap.put(id, responseObservable);
} else {
log.info("Another thread created the observable for us");
}
return subscriptionMap.get(id);
}
}
}
I think I've gotten it to work using .groupBy(...).
In my case Response.getValue() returns an int, but you get the idea:
class Adapter
{
Subject<Response> msgSubject;
ThirdPartyService service;
Map<String, Observable<Integer>> observables;
Observable<GroupedObservable<String, Response>> groupedObservables;
public Adapter()
{
msgSubject = PublishSubject.<Response>create().toSerialized();
service = new MockThirdPartyService( msgSubject::onNext );
groupedObservables = msgSubject.groupBy( Response::getId );
observables = Collections.synchronizedMap( new HashMap<>() );
}
public Observable<Integer> getObservable( String id )
{
return observables.computeIfAbsent( id, this::doCreateObservable );
}
private Observable<Integer> doCreateObservable( String id )
{
service.subscribe( id );
return groupedObservables
.filter( group -> group.getKey().equals( id ))
.doOnDispose( () -> {
synchronized ( observables )
{
service.unsubscribe( id );
observables.remove( id );
}
} )
.concatMap( Functions.identity() )
.map( Response::getValue )
.replay( 1 )
.refCount();
}
}
I'm working on cache implementation with RxJava 2. What I need is when network request fails, my repository would insert stale data and show error message. While I'm able to insert Item with .onErrorReturnItem(cachedItem) the error gets lost. Also I'm able to concat cached data with network request, but it is a bit cumbersome:
public Observable<Dashboard> getDashboard(String phoneNum, boolean getNewData) {
if (getNewData) invalidateDashboardCache();//just set dashboardCacheValid = false
Observable<Dashboard> observableToCache = Observable.fromCallable(
() -> {
Dashboard cached = mCache.getDashboard(phoneNum);
if (cached != null) {
if (!cached.cacheValid()) {
dashboardCacheValid = false;
}
return cached;
}
dashboardCacheValid = false;
return Dashboard.EMPTY;
})
.concatMap(cachedDashboard -> Observable.concat(Observable.just(cachedDashboard),
Observable.fromCallable(() -> !dashboardCacheValid)
.filter(Boolean::booleanValue)
.flatMap(cacheNotValid -> mNetworkHelper.getDashboardRaw(phoneNum))
.doOnNext(dashboard -> {
mCache.putDashboard(pnumber, dashboard);
dashboardCacheValid = true;
})));
return cacheObservable(CACHE_PREFIX_GET_DASHBOARD + phoneNum, observableToCache); //this is for multiple calls
}
Is there a way to modify .onErrorReturnItem(cachedDashboard) to something like this?:
Thanks to #akarnokd I was able to solve it properly and with much cleaner code:
public Observable<Dashboard> getDashboardNew(String phoneNum, boolean getNewData) {
Dashboard fromCache = mCache.getDashboard(phoneNum, getNewData);
dashboardCacheValid = fromCache.cacheValid();
if (getNewData) invalidateDashboardCache();
if (dashboardCacheValid) {
return Observable.just(fromCache);
} else {
final Dashboard cached = fromCache;
Observable<Dashboard> observableToCache = mNetworkHelper.getDashboardRaw(phoneNum)
.doOnNext(dashboard -> mCache.putDashboard(phoneNum, dashboard))
.onErrorResumeNext(throwable -> {
return Observable.concat(Observable.just(cached), Observable.error(throwable));
});
return cacheObservable(CACHE_PREFIX_GET_DASHBOARD + phoneNum, observableToCache);
}
}
I am having a lot of trouble understanding the zip operator in RxJava for my android project.
Problem
I need to be able to send a network request to upload a video
Then i need to send a network request to upload a picture to go with it
finally i need to add a description and use the responses from the previous two requests to upload the location urls of the video and picture along with the description to my server.
I assumed that the zip operator would be perfect for this task as I understood we could take the response of two observables (video and picture requests) and use them for my final task.
But I cant seem to get this to occur how I envision it.
I am looking for someone to answer how this can be done conceptually with a bit of psuedo code.
Thank you
Zip operator strictly pairs emitted items from observables. It waits for both (or more) items to arrive then merges them. So yes this would be suitable for your needs.
I would use Func2 to chain the result from the first two observables.
Notice this approach would be simpler if you use Retrofit since its api interface may return an observable. Otherwise you would need to create your own observable.
// assuming each observable returns response in the form of String
Observable<String> movOb = Observable.create(...);
// if you use Retrofit
Observable<String> picOb = RetrofitApiManager.getService().uploadPic(...),
Observable.zip(movOb, picOb, new Func2<String, String, MyResult>() {
#Override
public MyResult call(String movieUploadResponse, String picUploadResponse) {
// analyze both responses, upload them to another server
// and return this method with a MyResult type
return myResult;
}
}
)
// continue chaining this observable with subscriber
// or use it for something else
A small example:
val observableOne = Observable.just("Hello", "World")
val observableTwo = Observable.just("Bye", "Friends")
val zipper = BiFunction<String, String, String> { first, second -> "$first - $second" }
Observable.zip(observableOne, observableTwo, zipper)
.subscribe { println(it) }
This will print:
Hello - Bye
World - Friends
In BiFunction<String, String, String> the first String the type of the first observable, the second String is the type of the second observable, the third String represents the type of the return of your zipper function.
I made a small example that calls two real endpoints using zip in this blog post
Here I have an example that I did using Zip in asynchronous way, just in case you´re curious
/**
* Since every observable into the zip is created to subscribeOn a diferent thread, it´s means all of them will run in parallel.
* By default Rx is not async, only if you explicitly use subscribeOn.
*/
#Test
public void testAsyncZip() {
scheduler = Schedulers.newThread();
scheduler1 = Schedulers.newThread();
scheduler2 = Schedulers.newThread();
long start = System.currentTimeMillis();
Observable.zip(obAsyncString(), obAsyncString1(), obAsyncString2(), (s, s2, s3) -> s.concat(s2)
.concat(s3))
.subscribe(result -> showResult("Async in:", start, result));
}
/**
* In this example the the three observables will be emitted sequentially and the three items will be passed to the pipeline
*/
#Test
public void testZip() {
long start = System.currentTimeMillis();
Observable.zip(obString(), obString1(), obString2(), (s, s2, s3) -> s.concat(s2)
.concat(s3))
.subscribe(result -> showResult("Sync in:", start, result));
}
public void showResult(String transactionType, long start, String result) {
System.out.println(result + " " +
transactionType + String.valueOf(System.currentTimeMillis() - start));
}
public Observable<String> obString() {
return Observable.just("")
.doOnNext(val -> {
System.out.println("Thread " + Thread.currentThread()
.getName());
})
.map(val -> "Hello");
}
public Observable<String> obString1() {
return Observable.just("")
.doOnNext(val -> {
System.out.println("Thread " + Thread.currentThread()
.getName());
})
.map(val -> " World");
}
public Observable<String> obString2() {
return Observable.just("")
.doOnNext(val -> {
System.out.println("Thread " + Thread.currentThread()
.getName());
})
.map(val -> "!");
}
public Observable<String> obAsyncString() {
return Observable.just("")
.observeOn(scheduler)
.doOnNext(val -> {
System.out.println("Thread " + Thread.currentThread()
.getName());
})
.map(val -> "Hello");
}
public Observable<String> obAsyncString1() {
return Observable.just("")
.observeOn(scheduler1)
.doOnNext(val -> {
System.out.println("Thread " + Thread.currentThread()
.getName());
})
.map(val -> " World");
}
public Observable<String> obAsyncString2() {
return Observable.just("")
.observeOn(scheduler2)
.doOnNext(val -> {
System.out.println("Thread " + Thread.currentThread()
.getName());
})
.map(val -> "!");
}
You can see more examples here https://github.com/politrons/reactive
zip operator allow you to compose a result from results of two different observable.
You 'll have to give am lambda that will create a result from datas emitted by each observable.
Observable<MovieResponse> movies = ...
Observable<PictureResponse> picture = ...
Observable<Response> response = movies.zipWith(picture, (movie, pic) -> {
return new Response("description", movie.getName(), pic.getUrl());
});
i have been searching for a simple answer on how to use the Zip operator, and what to do with the Observables i create to pass them to it, i was wondering if i should call subscribe() for every observable or not, non of these answers were simple to find, i had to figure it out by my self, so here is a simple example for using Zip operator on 2 Observables :
#Test
public void zipOperator() throws Exception {
List<Integer> indexes = Arrays.asList(0, 1, 2, 3, 4);
List<String> letters = Arrays.asList("a", "b", "c", "d", "e");
Observable<Integer> indexesObservable = Observable.fromIterable(indexes);
Observable<String> lettersObservable = Observable.fromIterable(letters);
Observable.zip(indexesObservable, lettersObservable, mergeEmittedItems())
.subscribe(printMergedItems());
}
#NonNull
private BiFunction<Integer, String, String> mergeEmittedItems() {
return new BiFunction<Integer, String, String>() {
#Override
public String apply(Integer index, String letter) throws Exception {
return "[" + index + "] " + letter;
}
};
}
#NonNull
private Consumer<String> printMergedItems() {
return new Consumer<String>() {
#Override
public void accept(String s) throws Exception {
System.out.println(s);
}
};
}
the printed result is :
[0] a
[1] b
[2] c
[3] d
[4] e
the final answers to the questions that where in my head were as follows
the Observables passed to the zip() method just need to be created only, they do not need to have any subscribers to them, only creating them is enough ... if you want any observable to run on a scheduler, you can specify this for that Observable ... i also tried the zip() operator on Observables where they should wait for there result, and the Consumable of the zip() was triggered only when both results where ready (which is the expected behavior)
This is my implementation using Single.zip and rxJava2
I tried to make it as easy to understand as possible
//
// API Client Interface
//
#GET(ServicesConstants.API_PREFIX + "questions/{id}/")
Single<Response<ResponseGeneric<List<ResponseQuestion>>>> getBaseQuestions(#Path("id") int personId);
#GET(ServicesConstants.API_PREFIX + "physician/{id}/")
Single<Response<ResponseGeneric<List<ResponsePhysician>>>> getPhysicianInfo(#Path("id") int personId);
//
// API middle layer - NOTE: I had feedback that the Single.create is not needed (but I haven't yet spent the time to improve it)
//
public Single<List<ResponsePhysician>> getPhysicianInfo(int personId) {
return Single.create(subscriber -> {
apiClient.getPhysicianInfo(appId)
.subscribeOn(Schedulers.io())
.observeOn(Schedulers.io())
.subscribe(response -> {
ResponseGeneric<List<ResponsePhysician>> responseBody = response.body();
if(responseBody != null && responseBody.statusCode == 1) {
if (!subscriber.isDisposed()) subscriber.onSuccess(responseBody.data);
} else if(response.body() != null && response.body().status != null ){
if (!subscriber.isDisposed()) subscriber.onError(new Throwable(response.body().status));
} else {
if (!subscriber.isDisposed()) subscriber.onError(new Throwable(response.message()));
}
}, throwable -> {
throwable.printStackTrace();
if(!subscriber.isDisposed()) subscriber.onError(throwable);
});
});
}
public Single<List<ResponseQuestion>> getHealthQuestions(int personId){
return Single.create(subscriber -> {
apiClient.getBaseQuestions(personId)
.subscribeOn(Schedulers.io())
.observeOn(Schedulers.io())
.subscribe(response -> {
ResponseGeneric<List<ResponseQuestion>> responseBody = response.body();
if(responseBody != null && responseBody.data != null) {
if (!subscriber.isDisposed()) subscriber.onSuccess(response.body().data);
} else if(response.body() != null && response.body().status != null ){
if (!subscriber.isDisposed()) subscriber.onError(new Throwable(response.body().status));
} else {
if (!subscriber.isDisposed()) subscriber.onError(new Throwable(response.message()));
}
}, throwable -> {
throwable.printStackTrace();
if(!subscriber.isDisposed()) subscriber.onError(throwable);
});
});
}
//please note that ResponseGeneric is just an outer wrapper of the returned data - common to all API's in this project
public class ResponseGeneric<T> {
#SerializedName("Status")
public String status;
#SerializedName("StatusCode")
public float statusCode;
#SerializedName("Data")
public T data;
}
//
// API end-use layer - this gets close to the UI so notice the oberver is set for main thread
//
private static class MergedResponse{// this is just a POJO to store all the responses in one object
public List<ResponseQuestion> listQuestions;
public List<ResponsePhysician> listPhysicians;
public MergedResponse(List<ResponseQuestion> listQuestions, List<ResponsePhysician> listPhysicians){
this.listQuestions = listQuestions;
this.listPhysicians = listPhysicians;
}
}
// example of Single.zip() - calls getHealthQuestions() and getPhysicianInfo() from API Middle Layer
private void downloadHealthQuestions(int personId) {
addRxSubscription(Single
.zip(getHealthQuestions(personId), getPhysicianInfo(personId), MergedResponse::new)
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(response -> {
if(response != null) {
Timber.i(" - total health questions downloaded %d", response.listQuestions.size());
Timber.i(" - physicians downloaded %d", response.listPhysicians.size());
if (response.listPhysicians != null && response.listPhysicians.size()>0) {
// do your stuff to process response data
}
if (response.listQuestions != null && response.listQuestions.size()>0) {
// do your stuff to process response data
}
} else {
// process error - show message
}
}, error -> {
// process error - show network error message
}));
}
You use the zip from rxjava with Java 8:
Observable<MovieResponse> movies = ...
Observable<PictureResponse> picture = ...
Observable<ZipResponse> response = Observable.zip(movies, picture, ZipResponse::new);
class ZipResponse {
private MovieResponse movieResponse;
private PictureResponse pictureResponse;
ZipResponse(MovieResponse movieResponse, PictureResponse pictureResponse) {
this.movieResponse = movieResponse;
this.pictureResponse = pictureResponse;
}
public MovieResponse getMovieResponse() {
return movieResponse;
}
public void setMovieResponse(MovieResponse movieResponse) {
this.movieResponse= movieResponse;
}
public PictureResponse getPictureResponse() {
return pictureResponse;
}
public void setPictureResponse(PictureResponse pictureResponse) {
this.pictureResponse= pictureResponse;
}
}
You can use .zipWith operator for Observable chains.
If uploadMovies() and uploadPictures() return Observable,
uploadMovies()
.zipWith(uploadPictures()) { m, p ->
"$m with $p were uploaded"
}
.subscribe { print(it) }