I wanted to create a wrapper for api calls in retrofit so I can display ProgressDialog at common place & handle common response.
I achieved this by creating wrapper like this
public static <T> Observable<T> callApiWrapper(final Context context,
final boolean shouldShowProgress,
final String message,
final Observable<T> source) {
final ProgressDialog progressDialog = new ProgressDialog(context);
if (shouldShowProgress) {
if (!TextUtils.isEmpty(message))
progressDialog.setMessage(message);
else
progressDialog.setMessage(context.getString(R.string.please_wait));
}
return source.lift(new Observable.Operator<T, T>() {
#Override
public Subscriber<? super T> call(final Subscriber<? super T> child) {
return new Subscriber<T>() {
#Override
public void onStart() {
super.onStart();
if (shouldShowProgress) {
new Handler(Looper.getMainLooper()).post(new Runnable() {
#Override
public void run() {
progressDialog.show();
}
});
}
child.onStart();
}
#Override
public void onCompleted() {
if (shouldShowProgress && progressDialog.isShowing())
progressDialog.dismiss();
child.onCompleted();
}
#Override
public void onError(Throwable e) {
if (shouldShowProgress && progressDialog.isShowing())
progressDialog.dismiss();
child.onError(e);
}
#Override
public void onNext(T t) {
/*
Handle Invalid API response
*/
if (((BaseResponse) t).getStatus() == RestParams.Codes.INVALID_API_KEY) {
mCommonDataModel.setApiKey("");
getCommonApiService().getApiKey()
.subscribeOn(Schedulers.newThread())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(new Subscriber<ResponseBody>() {
#Override
public void onCompleted() {
}
#Override
public void onError(Throwable e) {
}
#Override
public void onNext(ResponseBody responseBody) {
try {
String response = responseBody.string();
JSONObject jsonObject = new JSONObject(response);
String key = jsonObject.optString("KEY");
if (!TextUtils.isEmpty(key))
mCommonDataModel.setApiKey(key);
callApiWrapper(context, shouldShowProgress,
message, source)
.subscribeOn(Schedulers.newThread())
.observeOn(AndroidSchedulers.mainThread())
.subscribe();
} catch (Exception e) {
e.printStackTrace();
}
}
});
} else {
if (shouldShowProgress && progressDialog.isShowing())
progressDialog.dismiss();
child.onNext(t);
}
}
};
}
});
}
In the above code, I check that if I get specific status code like Invalid API KEY, then I am calling an API to get the new API key instead of giving the status directly to original subscriber.
Once I get the new API key successfully, I call the wrapper recursively & try to give the response to original subscriber. But the problem is Original Subscriber is not getting onNext callback
What am I missing here? Is there any other way of achieving what I am trying to do?
You need to add some retry logic in case you get an invalid key failure so something like
source.flatMap(
t ->
{
if (((BaseResponse) t).getStatus() == RestParams.Codes.INVALID_API_KEY) {
return Observable.error(new InvalidKeyException("The key is not valid"));
}
else {
return Observable.just(t);
}
}
)
.retryWhen(
errors ->
errors.flatMap(error -> {
if (error instanceof InvalidKeyException()) {
return getCommonApiService().getApiKey()
.flatMap(
responseBody -> {
String response = responseBody.string();
JSONObject jsonObject = new JSONObject(response);
String key = jsonObject.optString("KEY");
if (TextUtils.isEmpty(key))
return Observable.error();
else {
return Observable.just(key);
}})
.doOnNext( key -> mCommonDataModel.setApiKey(key));
}
// For anything else, don't retry
return Observable.error(error);
}))
.subscribe(/* do what you need to do with the results*/)
In order to add the side effects i.e. enable progress bar when you start the subscription and dismiss it when you've finished something like
modifiedSource.doOnSubscribe(/* progress bar show logic */)
.doOnTerminate(/* progress bar dismiss logic */)
Finally I managed to create a wrapper which handles for me the common Progressbar & retry logic in case of Invalid Key API Response. This kind of wrapper might be useful if in many cases. Thanks to #JohnWowUs for his answer which helped me to understand things & implement this wrapper.
Here's the working code
private static final int MAX_RETRIES = 2;
private static int sCurrentRetryAttempt = 0;
/**
* Common Wrapper for calling API.
*
* #param context context for showing progress dialog
* #param shouldShowProgress boolean which indicated if progress dialog should be shown or not
* #param message message to be shown in progress dialog. if null passed, then "Please wait..." will be shown
* #param source original observable
* #return observable to which observer can subscribe
*/
public static <T> Observable<T> callApiWrapper(final Context context,
final boolean shouldShowProgress,
final String message,
final Observable<T> source) {
// Progress Dialog
final ProgressDialog progressDialog = setupProgressDialog(context, shouldShowProgress, message);
if (progressDialog != null) progressDialog.show();
return source
.flatMap(new Func1<T, Observable<T>>() {
#Override
public Observable<T> call(T t) {
/*
* Check if the response contains invalid key status code.
*/
if (t instanceof BaseResponse) {
if (((BaseResponse) t).getStatus() == RestParams.Codes.INVALID_API_KEY) {
return Observable.error(new InvalidKeyException("Invalid key"));
}
}
/*
* We are here, that means, there wasn't invalid key status code.
* So we wouldn't like to handle it so just return to original subscriber
*/
if (progressDialog != null && progressDialog.isShowing())
progressDialog.dismiss();
return Observable.just(t);
}
}).retryWhen(new Func1<Observable<? extends Throwable>, Observable<?>>() {
#Override
public Observable<?> call(Observable<? extends Throwable> observable) {
return observable.flatMap(new Func1<Throwable, Observable<?>>() {
#Override
public Observable<?> call(final Throwable throwable) {
if (throwable instanceof InvalidKeyException) {
/*
* Check for retry limit. if we already have retried enough, then
* we should tell the original subscriber about the error as it
* doesn't seems recoverable.
*/
if (sCurrentRetryAttempt >= MAX_RETRIES) {
if (progressDialog != null && progressDialog.isShowing())
progressDialog.dismiss();
//Resetting the attempts to 0
sCurrentRetryAttempt = 0;
return Observable.error(throwable);
}
//Increase the attempt counter
sCurrentRetryAttempt += 1;
return getCommonApiService().getApiKey()
.subscribeOn(Schedulers.newThread())
.observeOn(AndroidSchedulers.mainThread())
.flatMap(new Func1<ResponseBody, Observable<?>>() {
#Override
public Observable<?> call(ResponseBody responseBody) {
try {
/*
* Check if we succeed in our attempt to handle
* invalid key
*/
if (processApiKey(responseBody)) {
/*
* We succeeded in our attempts to handle
* invalid api key, so we will return the
* original subscriber what it wanted.
*/
return callApiWrapper(context,
shouldShowProgress, message, source);
} else
return Observable.just(throwable);
} catch (Exception e) {
/*
* We are here that means something went wrong,
* so we will retry silently.
*/
return Observable.just(throwable);
}
}
});
} else {
/*
* For any other error, we are not going to handle right now,
* so just return
*/
return Observable.error(throwable);
}
}
});
}
});
}
& using this is same as normal like:
RestClient.callApiWrapper(mContext, true, null,
RestClient.getAuthenticationApiService().socialLogIn(name, email, singInVia, mobile, "android", deviceToken))
.subscribeOn(Schedulers.newThread())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(new Subscriber<BaseResponse<RegistrationResponse>>() {
//...
}
Related
In my android app I have an option to backup the database to Google Drive. For that I am using DriveServiceHelper class, but I just noticed, in Android 11 the Task.call is deprecated.
public Task<FileList> queryFiles() {
return Tasks.call(mExecutor, () ->
mDriveService.files().list().setSpaces("drive").execute());
}
From my BackupActivity then I call queryFiles from backup method:
public void backup(View v) {
driveServiceHelper.queryFiles()
.addOnSuccessListener(fileList -> {
// another code
})
.addOnFailureListener(e -> showMsgSnack(getString(R.string.uploaderror)));
I did not find any solution how to deal with this to avoid complete rework of that class.
What I tried:
I tried to replace with runnable, also callable, but it doesn't work as Task is expected to be returned, not Filelist.
also I tried to use TaskCompletionSource:
public Task<FileList> queryFiles(int delay) throws IOException, ExecutionException, InterruptedException {
new Thread(
new Runnable() {
#Override
public void run() {
TaskCompletionSource<FileList> taskCompletionSource = new TaskCompletionSource<>();
FileList result = null;
try {
result = mDriveService.files().list().setSpaces("drive").execute();
} catch (IOException e) {
e.printStackTrace();
}
FileList finalResult = result;
new Handler().postDelayed(() -> taskCompletionSource.setResult(finalResult), delay);
return taskCompletionSource.getTask();
}
}).start();
}
but the return works not from a method of void type.
Ok, after hours of testing I tried this solution and this seems working for now: (using executorService, and in Handler a Looper is needed.)
public Task<FileList> queryFiles() {
final TaskCompletionSource<FileList> tcs = new TaskCompletionSource<FileList>();
ExecutorService service = Executors.newFixedThreadPool(1);
service.execute(
new Runnable() {
#Override
public void run() {
FileList result = null;
try {
result = mDriveService.files().list().setSpaces("drive").execute();
} catch (IOException e) {
e.printStackTrace();
}
FileList finalResult = result;
new Handler(Looper.getMainLooper()).postDelayed(() -> tcs.setResult(finalResult), 1000);
}
});
return tcs.getTask();
}
I meant something like this:
public Task<FileList> queryFiles(int delay) throws IOException {
Task<FileList> retVal;
final FutureValue<Task<FileList>> future = new FutureValue<>();
// now run this bit in a runnable
/*
TaskCompletionSource<FileList> taskCompletionSource = new TaskCompletionSource<>();
FileList result = mDriveService.files().list().setSpaces("drive").execute();
new Handler().postDelayed(() -> taskCompletionSource.setResult(result), delay);
return taskCompletionSource.getTask();
*/
new Thread(
new Runnable() {
#Override
public void run() {
TaskCompletionSource<FileList> taskCompletionSource = new TaskCompletionSource<>();
FileList result = mDriveService.files().list().setSpaces("drive").execute();
new Handler().postDelayed(() -> taskCompletionSource.setResult(result), delay);
// and we replace the return statement with something else
// return taskCompletionSource.getTask();
future.set(taskCompletionSource.getTask());
}
}).start();
// And block (wait) for future to finish so we can return it, deadlocking the main thread...
// return future.get();
//FIXME do either this
// retVal = future.get();
// For bonus points, we'll do a timed wait instead -- OR THIS
try {
retVal = future.get(30, TimeUnit.SECONDS);
} catch (TimeoutException e) {
future.cancel(true);
Log.d(LOG_TAG, "Exception "+e+" happened!", e);
} catch (InterruptedException | ExecutionException e) {
Log.d(LOG_TAG, "Exception "+e+" happened!", e);
}
return retVal;
}
and that should set you on some path to solving the problem.
However, if the only reason for using the Task<> is just so you can add success/fail listeners to these methods - i strongly suggest you come up with something better that actually runs on background threads instead of the thread you're calling them on.
The FutureValue class:
/**
* Implementation of {#link Future}, allowing waiting for value to be set (from another thread).
* Use {#link #set(Object)} to set value, {#link #get()} or {#link #get(long, TimeUnit)} to retrieve
* value.
* TODO: tests
*
* #param <T> type of awaited value
*/
public class FutureValue<T> implements Future<T> {
private static final String LOGTAG = "FutureValue";
private static final long NANOS_IN_MILLI = TimeUnit.MILLISECONDS.toNanos(1);
private volatile T value;
private volatile boolean isDone = false;
private volatile boolean isCanceled = false;
/**
* Sets value awaited by this future.
*
* #param value value
*/
public synchronized void set(T value) {
this.value = value;
isDone = true;
notifyAll();
}
/** {#inheritDoc} */
#Override
public synchronized boolean cancel(boolean mayInterruptIfRunning) {
isCanceled = true;
notifyAll();
return !isDone;
}
/** {#inheritDoc} */
#Override
public boolean isCancelled() {
return isCanceled;
}
/** {#inheritDoc} */
#Override
public boolean isDone() {
return isDone;
}
/** {#inheritDoc} */
#Override
public synchronized T get() {
while (!isDone) {
if (isCanceled) {
return value;
}
try {
wait();
} catch (InterruptedException ignored) {
Log.w(LOGTAG, "We're just gonna ignore this exception: " + ignored, ignored);
}
}
return value;
}
/** {#inheritDoc} */
#Override
public synchronized T get(long timeout, #NonNull TimeUnit unit)
throws InterruptedException, ExecutionException, TimeoutException {
final long targetTime = System.nanoTime() + unit.toNanos(timeout);
while (!isDone && !isCanceled) {
try {
final long waitTimeNanos = targetTime - System.nanoTime();
if (waitTimeNanos <= 0) {
throw new TimeoutException();
}
wait(waitTimeNanos / NANOS_IN_MILLI, (int) (waitTimeNanos % NANOS_IN_MILLI));
} catch (InterruptedException ignored) {
Log.w(LOGTAG, "We're just gonna ignore this exception: " + ignored, ignored);
}
}
return value;
}
}
I'm trying to convert a callback hell to RX but I'm stuck with getting the proper order, below is my functionality I want to achieve
a) User Login-> get the Auth Cookies, if login credentials invalid show error message
b) use the Auth Cookies to get Customer Type,
c) if the Customer Type is zero/ show profile Restricted Error Message and log out the user
d) if the customerType, not zero proceed to get the other customer Details
e) if any of the customer APIs returns an error response, log out the user and show login failure message
f) if all customer API success show the home screen
API
Login
#FormUrlEncoded
#POST("distauth/UI/Login")
Single<Response<Void>> doLogin1(#Field("username") String username, #Field("password") String password,
#Field("rememberme") String rememberMe, #Field("answer") String answer,
#QueryMap Map<String, String> options);
public Single<Boolean> doLogin(#NonNull String username, #Nullable String password) {
return authapi.doLogin1(username, password, "y", "", logiOptions)
.flatMap(new Function<Response<Void>, SingleSource<Boolean>>() {
#Override
public SingleSource<Boolean> apply(Response<Void> response) throws Exception {
if (response.code() == HttpStatus.MOVED_TEMPORARILY.value()
&& !StringUtils.isEmpty(Session.getCookie())
) {
return Single.just(true);
}
throw new Exception("Invalid Login Details");
}
});
}
//==========
Logout
#FormUrlEncoded
#POST("distauth/UI/Logout")
#Headers("Cache-Control: no-cache")
Completable doLogout(#Field("logout") boolean logout); //return 302 HTTP Status code with empty iPlanetCookie
//==========
NOTE: Loing/logout is not a REST API, this legacy app implement as Form Post ;) so when the success of login return 302 with cookies, and log out also return 302 as status code
Get Customer Details
Single<CustomerAccountVO> getCustomerAccountDetails(boolean forceRefresh);
//==========
Single<CustomerType> getCustomerUserProfile(boolean forceRefresh);
#Override
public Single<CustomerType> getCustomerUserProfile(boolean applyResponseCache) {
return this.mCustomerRemoteDataStore.getCustomerUserProfile(applyResponseCache)
.doOnSuccess(new Consumer<CustomerType>() {
#Override
public void accept(CustomerType customerType) throws Exception {
if (customerType != null && customerType.getBody() != null &&
!StringUtils.isEmpty(customerType.getBody())) {
if (customerType.getBody().equalsIgnoreCase(AppConfig.ERROR)) {
throw new CustomerProfileNotFound(500, "user account restrictions");
} else {
mCustomerLocalRepository.saveCustomerType(customerType);
}
}
}
}).doOnError(new Consumer<Throwable>() {
#Override
public void accept(Throwable throwable) throws Exception {
Log.e(TAG, "error occurred while getting customer user profile", throwable);
}
});
}
//==========
Single<CustomerAccountId> getAccountId(boolean forceRefresh);
//==========
Single<Customer> getCustomer(boolean forceRefresh);
//==========
Get Customer Full Details
Single<CustomerDetails> getCustomerFullDetails(boolean applyResponseCache);
Implementation:
#Override
public Single<CustomerDetails> getCustomerFullDetails(boolean forceRefresh) {
Single<CustomerDetails> customerDetails = Single.zip(
getCustomerUserProfile(forceRefresh).subscribeOn(Schedulers.io()),
getAccountId(forceRefresh).subscribeOn(Schedulers.io()),
getCustomerAccountDetails(false).subscribeOn(Schedulers.io()),
getCustomer(forceRefresh).subscribeOn(Schedulers.io()), new Function4<CustomerType, CustomerAccountId,
CustomerAccountVO, Customer, CustomerDetails>() {
#Override
public CustomerDetails apply(#NonNull CustomerType customerType,
#NonNull CustomerAccountId customerAccountId,
#NonNull CustomerAccountVO customerAccountVO,
#NonNull Customer customer) throws Exception {
return CustomerDetails.builder().customerType(customerType).customerAccountVO
(customerAccountVO).customer(customer).customerAccountId(customerAccountId).
build();
}
});
return customerDetails;
}
//==========
Each customer request is independent so I thought to execute as sperate thread and zip the final result/
Single<BaseServerResponse> updateCustomerDetails(#Nonnull boolean secure, int secureRequestCode, #Nonnull JSONObject customerContact);
//Presenter Implementation: this implementation not working as i expect above, can some one help me to get this correct,
public void doLoginHandler(#NonNull String username, #NonNull String password) {
checkViewAttached();
getMvpView().showLoadingIndicator();
addSubscription(
apiService.doLogin2(username, password)
.subscribeOn(Schedulers.io())
.flatMap(new Function<Boolean, SingleSource<CustomerDetails>>() {
#Override
public SingleSource<CustomerDetails> apply(Boolean aBoolean) throws Exception {
if (aBoolean) {
//get customr Full Details
Log.d(TAG, "apply: "+aBoolean);
return customerRepository.getCustomerFullDetails(true);
}
return null;
}
}).observeOn(AndroidSchedulers.mainThread())
.onErrorResumeNext(new Function<Throwable, SingleSource<? extends CustomerDetails>>() {
#Override
public SingleSource<? extends CustomerDetails> apply(Throwable throwable) throws Exception {
if (throwable instanceof CustomerProfileNotFound) {
getMvpView().showUserProfileAccessRestrictMessage();
} else {
getMvpView().onLoginAuthFailure();
}
return Single.just(CustomerDetails.builder().errorOccurred(true).build());
}
})
.flatMapCompletable(new Function<CustomerDetails, CompletableSource>() {
#Override
public CompletableSource apply(CustomerDetails customerDetails) throws Exception {
if(customerDetails.isErrorOccurred()){
return apiService.doLogout();
}
return Completable.complete();
}
})
.subscribe(new Action() {
#Override
public void run() throws Exception {
getMvpView().onLoginAuthSuccess();
}
}, new Consumer<Throwable>() {
#Override
public void accept(Throwable throwable) throws Exception {
if (throwable instanceof CustomerProfileNotFound) {
getMvpView().showUserProfileAccessRestrictMessage();
} else {
getMvpView().onLoginAuthFailure();
}
}
}));
}
First I'll state the problem with your code.
.flatMapCompletable(new Function<CustomerDetails, CompletableSource>() {
#Override
public CompletableSource apply(CustomerDetails customerDetails) throws Exception {
if(customerDetails.isErrorOccurred()){
return apiService.doLogout();
}
return Completable.complete();
}
})
This chain observable (which is the one you subscribe to) is always going to give a Completed state unless a network error happens when calling the logout API, that's because you either return the logout Completable or an instant Completable.
Secondly, I think the solution is in logically sorting everything out, the key to error handling in such a case would be creating a different Exception for each error case with it's own error message,
it can go like this (I'm just using the logical names, hopefully that will give you the idea):
loginObservable.flatMap { authCredentials -> {
if (authCredentials.isValid())
return getCustomerTypeObservable(authCredentials)
else
return Single.error(InvalidCredentialsException("message goes here (optional)"))
}}.flatMap { type -> {
if (type == 0)
return Single.error(ProfileRestrictedException("different message maybe?"))
else
return getCustomerDetailsZippedObservable(type)
}}
/* ..etc */
Then at the subscription site you do something like:
myObservable.subscribe( {
/* Handle success*/
}, { exception ->
when(exception) {
is InvalidCredentialsException -> mvpView.showError(message)
is ProfileRestrictedException -> {
mvpView.showError(message)
logout()
}
else -> /* Handle an exception that is not listed above */
}
} )
This way IMO is more convenient than using onErrorResumeNext.
EDIT: You can also overcome the issue stated above by doing something like:
.flatMapCompletable { customerDetails -> {
if(customerDetails.isErrorOccurred()){
return apiService.doLogout()
.then(Completable.error(LoginFailedException("Message"))) /* This will guarantee the stream terminates with the required error type after logout is successful */
} else {
return Completable.complete()
}
}}
I am trying to call the web service to fetch the data and storing it into database using following code. I have created a separate class to perform following operation.
Now , the issue is i want to notify my activity when i successfully fetch and store data in database. if some error occurs then i want to show that on UI itself.
somehow i am able to write a code to fetch the data using pagination but not sure how would i notify UI where i can subscribe catch the update related to progress and error if any.
public Flowable<Response> getFitnessData() {
Request request = new Request();
request.setAccess_token("d80fa6bd6f78cc704104d61146c599bc94b82ca225349ee68762fc6c70d2dcf0");
Flowable<Response> fitnessFlowable = new WebRequest()
.getRemoteClient()
.create(FitnessApi.class)
.getFitnessData("5b238abb4d3590001d9b94a8",request.toMap());
fitnessFlowable.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.takeUntil(response->response.getSummary().getNext()!=null)
.subscribe(new Subscriber<Response>() {
#Override
public void onSubscribe(Subscription s) {
s.request(Long.MAX_VALUE);
}
#Override
public void onNext(Response response) {
Log.e(TAG, "onNext" );
if(response !=null){
if(response.getFitness()!=null && response.getFitness().size()!=0){
Realm realm = Realm.getDefaultInstance();
realm.executeTransactionAsync(new Realm.Transaction() {
#Override
public void execute(Realm realm) {
realm.copyToRealmOrUpdate(response.getFitness());
}
}, new Realm.Transaction.OnSuccess() {
#Override
public void onSuccess() {
Log.i(TAG, "onSuccess , fitness data saved");
}
}, new Realm.Transaction.OnError() {
#Override
public void onError(Throwable error) {
Log.i(TAG, "onError , fitness data failed to save"+error.getMessage() );
}
});
}else{
Log.i(TAG, "onError , no fitness data available" );
}
}else{
Log.i(TAG, "onError , response is null" );
}
}
#Override
public void onError(Throwable t) {
Log.e(TAG, "onError" +t.getMessage());
}
#Override
public void onComplete() {
Log.e(TAG, "onComplete");
}
});;
return null;
}
Updated
Created RxBus to propagate events and error on UI
public class RxBus {
private static final RxBus INSTANCE = new RxBus();
private RxBus(){}
private PublishSubject<Object> bus = PublishSubject.create();
public static RxBus getInstance() {
return INSTANCE;
}
public void send(Object o) {
bus.onNext(o);
}
public void error(Throwable e){bus.onError(e);}
public Observable<Object> toObservable() {
return bus;
}
}
in activity
FitnessRepo fitnessRepo = new FitnessRepo();
fitnessRepo.getFitnessData();
RxBus.getInstance().toObservable().subscribe(new Observer<Object>() {
#Override
public void onSubscribe(Disposable d) {
}
#Override
public void onNext(Object o) {
if(o instanceof RealmList ){
RealmList<Fitness> realmList = (RealmList<Fitness>) o;
Log.e(TAG,"Fitness data size "+realmList.size());
}
}
#Override
public void onError(Throwable e) {
Log.e(TAG,e.getMessage()+ "");
if (e instanceof HttpException) {
ResponseBody body = ((HttpException) e).response().errorBody();
try {
Response response= LoganSquare.parse(body.byteStream(),Response.class);
if(response.getErrors() !=null)
if(response.getErrors().size() > 0)
Log.e(TAG, "Error "+response.getErrors().get(0).getErrors());
} catch (IOException t) {
t.printStackTrace();
}
}
}
#Override
public void onComplete() {
}
});
in a web service call
public void getFitnessData() {
Request request = new Request();
request.setAccess_token("d80fa6bd6f78cc704104d61146c599bc94b82ca225349ee68762fc6c70d2dcf0");
request.setEnd_date("2018-07-01T00:00:00");
Flowable<Response> fitnessFlowable = new WebRequest()
.getRemoteClient()
.create(FitnessApi.class)
.getFitnessData("5b238abb4d3590001d9b94a8",request.toMap());
fitnessFlowable.subscribeOn(Schedulers.io())
.takeUntil(response->response.getSummary().getNext()!=null)
.doOnNext((response) -> {
if(response ==null || response.getFitness() == null || response.getFitness().isEmpty()) {
Log.e(TAG, " Error ");
return;
}
RxBus.getInstance().send(response.getFitness());
try(Realm r = Realm.getDefaultInstance()) {
r.executeTransaction((realm) -> {
realm.copyToRealmOrUpdate(response.getFitness());
});
}
}).subscribe(item ->{
},
error ->{
RxBus.getInstance().error(error);
});
}
I have good news for you! You can delete almost all of that code and just make it generally better as a result!
public void fetchFitnessData() {
Request request = new Request();
request.setAccess_token("d80fa6bd6f78cc704104d61146c599bc94b82ca225349ee68762fc6c70d2dcf0");
Flowable<Response> fitnessFlowable = new WebRequest()
.getRemoteClient()
.create(FitnessApi.class)
.getFitnessData("5b238abb4d3590001d9b94a8",request.toMap());
fitnessFlowable.subscribeOn(Schedulers.io())
.takeUntil(response->response.getSummary().getNext()!=null)
.doOnNext((response) -> {
if(response ==null || response.getFitness() == null || response.getFitness().isEmpty()) return;
try(Realm r = Realm.getDefaultInstance()) {
r.executeTransaction((realm) -> {
realm.insertOrUpdate(response.getFitness());
});
}
}
}).subscribe();
}
This method is on a background thread now and returns void, so the way to emit stuff out of this method would be to use either a PublishSubject (one for success, one for failure) or an EventBus.
private PublishSubject<Object> fitnessResults;
public Observable<Object> observeFitnessResults() {
return fitnessResults;
}
public static class Success {
public Success(List<Fitness> data) {
this.data = data;
}
public List<Fitness> data;
}
public static class Failure {
public Failure(Exception exception) {
this.exception = exception;
}
public Exception exception;
}
public void fetchFitnessData() {
...
fitnessResults.onNext(new Success(data));
} catch(Exception e) {
fitnessResults.onNext(new Failure(e));
And then
errors = observeFitnessResults().ofType(Error.class);
success = observeFitnessResults().ofType(Success.class);
There are different ways to achieve this. I will never handle the subscriptions on my own out of a lifecycle scope as it creates a possibility of memory leak. In your case it seems that both success and failure is bound to the UI so you can simply do this.
public Completable fetchFitnessData() {
Request request = new Request();
request.setAccess_token("d80fa6bd6f78cc704104d61146c599bc94b82ca225349ee68762fc6c70d2dcf0");
Flowable<Response> fitnessFlowable = new WebRequest()
.getRemoteClient()
.create(FitnessApi.class)
.getFitnessData("5b238abb4d3590001d9b94a8",request.toMap());
return fitnessFlowable.subscribeOn(Schedulers.io())
.takeUntil(response->response.getSummary().getNext()!=null)
.doOnNext((response) -> {
if(response ==null || response.getFitness() == null || response.getFitness().isEmpty()) return;
try(Realm r = Realm.getDefaultInstance()) {
r.executeTransaction((realm) -> {
realm.insertOrUpdate(response.getFitness());
});
}
}
}).ignoreElements();
}
At UI level, you can just handle your subscription with both success and failure. In case you need success model can replace Completable with Single or Flowable.
fetchFitnessData.subscrible(Functions.EMPTY_ACTION, Timber::d);
The major advantage with this approach is that you handle your subscription lifecycles.
I am using RxJava2.
i have some observable, and few subscribers that can be subscribed for it.
each time when new subscribers arrive, some job should be done and each of subscribers should be notified.
for this i decide to use PublishSubject. but when doOnSubscribe received from firs subscriber, myPublishSubject.hasObservers() return false...
any idea why it happens and how can i fix this?
private val myPublishSubject = PublishSubject.create<Boolean>()
fun getPublishObservable():Observable<Boolean> {
return myPublishSubject.doOnSubscribe {
//do some job when new subscriber arrived and notify all subscribers
//via
myPublishSubject.onNext(true)
}
}
Do I understand it correct, that when doOnSubscribe called it mean that there is at least one subscribers already present?
i did not find ready answer, so i create my own version of subject and call it RefreshSubject.
it based on PublishSubject but with one difference: if you would like to return observable and be notified when new subscriber arrives and ready to receive some data you should use method getSubscriberReady.
here a small example:
private RefreshSubject<Boolean> refreshSubject = RefreshSubject.create();
//ordinary publish behavior
public Observable<Boolean> getObservable(){
return refreshSubject;
}
//refreshSubject behaviour
public Observable<Boolean> getRefreshObserver(){
return refreshSubject.getSubscriberReady(new Action() {
#Override
public void run() throws Exception {
//new subscriber arrives and ready to receive some data
//so you can make some data request and all your subscribers (with new one just arrived)
//will receive new content
}
});
}
and here is full class:
public class RefreshSubject<T> extends Subject<T> {
/** The terminated indicator for the subscribers array. */
#SuppressWarnings("rawtypes")
private static final RefreshSubject.RefreshDisposable[] TERMINATED = new RefreshSubject.RefreshDisposable[0];
/** An empty subscribers array to avoid allocating it all the time. */
#SuppressWarnings("rawtypes")
private static final RefreshSubject.RefreshDisposable[] EMPTY = new RefreshSubject.RefreshDisposable[0];
/** The array of currently subscribed subscribers. */
private final AtomicReference<RefreshDisposable<T>[]> subscribers;
/** The error, write before terminating and read after checking subscribers. */
Throwable error;
/**
* Constructs a RefreshSubject.
* #param <T> the value type
* #return the new RefreshSubject
*/
#CheckReturnValue
public static <T> RefreshSubject<T> create() {
return new RefreshSubject<T>();
}
/**
* Constructs a RefreshSubject.
* #since 2.0
*/
#SuppressWarnings("unchecked")
private RefreshSubject() {
subscribers = new AtomicReference<RefreshSubject.RefreshDisposable<T>[]>(EMPTY);
}
#Override
public void subscribeActual(Observer<? super T> t) {
RefreshSubject.RefreshDisposable<T> ps = new RefreshSubject.RefreshDisposable<T>(t, RefreshSubject.this);
t.onSubscribe(ps);
if (add(ps)) {
// if cancellation happened while a successful add, the remove() didn't work
// so we need to do it again
if (ps.isDisposed()) {
remove(ps);
}
} else {
Throwable ex = error;
if (ex != null) {
t.onError(ex);
} else {
t.onComplete();
}
}
}
public Observable<T> getSubscriberReady(final Action onReady){
return Observable.create(new ObservableOnSubscribe<T>() {
#Override
public void subscribe(ObservableEmitter<T> e) throws Exception {
add(new RefreshDisposable(e, RefreshSubject.this));
onReady.run();
}
});
}
/**
* Tries to add the given subscriber to the subscribers array atomically
* or returns false if the subject has terminated.
* #param ps the subscriber to add
* #return true if successful, false if the subject has terminated
*/
private boolean add(RefreshSubject.RefreshDisposable<T> ps) {
for (;;) {
RefreshSubject.RefreshDisposable<T>[] a = subscribers.get();
if (a == TERMINATED) {
return false;
}
int n = a.length;
#SuppressWarnings("unchecked")
RefreshSubject.RefreshDisposable<T>[] b = new RefreshSubject.RefreshDisposable[n + 1];
System.arraycopy(a, 0, b, 0, n);
b[n] = ps;
if (subscribers.compareAndSet(a, b)) {
return true;
}
}
}
/**
* Atomically removes the given subscriber if it is subscribed to the subject.
* #param ps the subject to remove
*/
#SuppressWarnings("unchecked")
private void remove(RefreshSubject.RefreshDisposable<T> ps) {
for (;;) {
RefreshSubject.RefreshDisposable<T>[] a = subscribers.get();
if (a == TERMINATED || a == EMPTY) {
return;
}
int n = a.length;
int j = -1;
for (int i = 0; i < n; i++) {
if (a[i] == ps) {
j = i;
break;
}
}
if (j < 0) {
return;
}
RefreshSubject.RefreshDisposable<T>[] b;
if (n == 1) {
b = EMPTY;
} else {
b = new RefreshSubject.RefreshDisposable[n - 1];
System.arraycopy(a, 0, b, 0, j);
System.arraycopy(a, j + 1, b, j, n - j - 1);
}
if (subscribers.compareAndSet(a, b)) {
return;
}
}
}
#Override
public void onSubscribe(Disposable s) {
if (subscribers.get() == TERMINATED) {
s.dispose();
}
}
#Override
public void onNext(T t) {
if (subscribers.get() == TERMINATED) {
return;
}
if (t == null) {
onError(new NullPointerException("onNext called with null. Null values are generally not allowed in 2.x operators and sources."));
return;
}
for (RefreshSubject.RefreshDisposable<T> s : subscribers.get()) {
s.onNext(t);
}
}
#SuppressWarnings("unchecked")
#Override
public void onError(Throwable t) {
if (subscribers.get() == TERMINATED) {
RxJavaPlugins.onError(t);
return;
}
if (t == null) {
t = new NullPointerException("onError called with null. Null values are generally not allowed in 2.x operators and sources.");
}
error = t;
for (RefreshSubject.RefreshDisposable<T> s : subscribers.getAndSet(TERMINATED)) {
s.onError(t);
}
}
#SuppressWarnings("unchecked")
#Override
public void onComplete() {
if (subscribers.get() == TERMINATED) {
return;
}
for (RefreshSubject.RefreshDisposable<T> s : subscribers.getAndSet(TERMINATED)) {
s.onComplete();
}
}
#Override
public boolean hasObservers() {
return subscribers.get().length != 0;
}
#Override
public Throwable getThrowable() {
if (subscribers.get() == TERMINATED) {
return error;
}
return null;
}
#Override
public boolean hasThrowable() {
return subscribers.get() == TERMINATED && error != null;
}
#Override
public boolean hasComplete() {
return subscribers.get() == TERMINATED && error == null;
}
/**
* Wraps the actualEmitter subscriber, tracks its requests and makes cancellation
* to remove itself from the current subscribers array.
*
* #param <T> the value type
*/
private static final class RefreshDisposable<T> extends AtomicBoolean implements Disposable {
private static final long serialVersionUID = 3562861878281475070L;
/** The actualEmitter subscriber. */
final Emitter<? super T> actualEmitter;
/** The actualEmitter subscriber. */
final Observer<? super T> actualObserver;
/** The subject state. */
final RefreshSubject<T> parent;
/**
* Constructs a PublishSubscriber, wraps the actualEmitter subscriber and the state.
* #param actualEmitter the actualEmitter subscriber
* #param parent the parent RefreshProcessor
*/
RefreshDisposable(Emitter<? super T> actualEmitter, RefreshSubject<T> parent) {
this.actualEmitter = actualEmitter;
this.parent = parent;
actualObserver = null;
}
/**
* Constructs a PublishSubscriber, wraps the actualEmitter subscriber and the state.
* #param actualObserver the actualObserver subscriber
* #param parent the parent RefreshProcessor
*/
RefreshDisposable(Observer<? super T> actualObserver, RefreshSubject<T> parent) {
this.actualObserver = actualObserver;
this.parent = parent;
actualEmitter = null;
}
public void onNext(T t) {
if (!get()) {
if (actualEmitter != null)
actualEmitter.onNext(t);
if (actualObserver != null)
actualObserver.onNext(t);
}
}
public void onError(Throwable t) {
if (get()) {
RxJavaPlugins.onError(t);
} else {
if (actualEmitter != null)
actualEmitter.onError(t);
if (actualObserver != null)
actualObserver.onError(t);
}
}
public void onComplete() {
if (!get()) {
if (actualEmitter != null)
actualEmitter.onComplete();
if (actualObserver != null)
actualObserver.onComplete();
}
}
#Override
public void dispose() {
if (compareAndSet(false, true)) {
parent.remove(this);
}
}
#Override
public boolean isDisposed() {
return get();
}
}
}
I'm pretty new to RxJava and Retrofit and am trying to write my API calls with it. All the API calls return a JSON body on error which is in the general format as,
{"errors":[{"code":100, "message":"Login/Password not valid", "arguments":null}]}
Currently my code for the login API call (others are also similar) is,
mConnect.login(id, password)
.subscribe(new Subscriber<Token>() {
#Override
public void onCompleted() {
Log.d(TAG, "onCompleted()");
}
#Override
public void onError(Throwable e) {
Log.e(TAG, "onError(): " + e);
if (e instanceof HttpException) {
// dump e.response().errorBody()
}
}
#Override
public void onNext(Token token) {
Log.d(TAG, "onNext(): " + token);
}
});
When I get an error at the onError(), I would like to automatically decode the JSON in the error body to a POJO instead and use that. Is there a way to do this preferably in one place for all other API calls. Any help is appreciated.
I would suggest the use of a reusable Transformer along with the onErrorResumeNext operator to encapsulate your logic. It'd look something like this:
<T> Observable.Transformer<T, T> parseHttpErrors() {
return new Observable.Transformer<T, T>() {
#Override
public Observable<T> call(Observable<T> observable) {
return observable.onErrorResumeNext(new Func1<Throwable, Observable<? extends T>>() {
#Override
public Observable<? extends T> call(Throwable throwable) {
if (throwable instanceof HttpException) {
HttpErrorPojo errorPojo = // deserialize throwable.response().errorBody();
// Here you have two options, one is report this pojo back as error (onError() will be called),
return Observable.error(errorPojo); // in this case HttpErrorPojo would need to inherit from Throwable
// or report this pojo back as part of onNext()
return Observable.just(errorPojo); //in this case HttpErrorPojo would need to inherit from <T>
}
// if not the kind we're interested in, then just report the same error to onError()
return Observable.error(throwable);
}
});
}
};
}
Pay attention to the comments in the code, since you have to make the decision whether you want to report the parsed response onError() or onNext().
Then you can use this transformer anywhere in your API calls like this:
mConnect.login(id, password)
.compose(this.<Token>parseHttpErrors()) // <-- HERE
.subscribe(new Subscriber<Token>() {
#Override
public void onCompleted() {
Log.d(TAG, "onCompleted()");
}
#Override
public void onError(Throwable e) {
Log.e(TAG, "onError(): " + e);
if (e instanceof HttpErrorPojo) {
// this will be called if errorPojo was reported via Observable.error()
}
}
#Override
public void onNext(Token token) {
Log.d(TAG, "onNext(): " + token);
if (token instanceof HttpErrorPojo) {
// this will be called if errorPojo was reported via Observable.just()
}
}
});
Deserialize may be an issue too. You can use the retrofit converter to deserialize it (or do it yourself).
My solution adds a bit to the one from murki:
<T> Observable.Transformer<T, T> parseHttpErrors() {
return new Observable.Transformer<T, T>() {
#Override
public Observable<T> call(Observable<T> observable) {
return observable.onErrorResumeNext(new Func1<Throwable, Observable<? extends T>>() {
#Override
public Observable<? extends T> call(Throwable throwable) {
if ( throwable instanceof HttpException ) {
Retrofit retrofit = new Retrofit.Builder()
.baseUrl(SERVER_URL) // write your url here
.addConverterFactory(GsonConverterFactory.create())
.build();
Converter<ResponseBody, Error> errorConverter =
retrofit.responseBodyConverter(Error.class, new Annotation[0]);
// Convert the error body into our Error type.
try {
Error error = errorConverter.convert(((HttpException) throwable).response().errorBody());
// Here you have two options, one is report this pojo back as error (onError() will be called),
return Observable.error(new Throwable(error.getMessage()));
}
catch (Exception e2) {
return Observable.error(new Throwable());
}
}
// if not the kind we're interested in, then just report the same error to onError()
return Observable.error(throwable);
}
});
}
};
}
and then at the onError(),
#Override
public void onError(Throwable e) {
progressBar.setVisibility(View.GONE); // optional
if ( !TextUtils.isEmpty(e.getMessage()) ) {
// show error as you like
return;
}
// show a default error if you wish
}