Confusing behavior of useExpiredDataWhenNoLoaderAvailable()

[vtarantik]

Hi,
I'd like to show the cached data and meanwhile download the new data in the background. If there's no cached data(first run), I simply show No data available TextView. What I tried so far is this:

ReactiveCache reactiveCache = new ReactiveCache.Builder() .diskCacheSize(30) .useExpiredDataWhenNoLoaderAvailable() .using(app.getFilesDir(),new GsonSpeaker()); return reactiveCache;

cacheProvider = reactiveCache.<ContactsList>provider() .lifeCache(5,TimeUnit.SECONDS) .withKey("contacts");

I'm using it like this:
apiInteractor.getContacts() .compose(cacheProvider.readWithLoader()) .subscribeOn(Schedulers.newThread()) .observeOn(mainThread()),

When I disabled the WiFi and reloaded the fragment, I expected the cached data to be emitted but I get the RxCacheException instead. Sorry if I'm missing something, I'm quite new in Rx. I've even tried expirable(false) but with no luck.

Stack trace:

W/System.err: io.rx_cache.RxCacheException: The Loader provided did not return any data and there is not data to load from the Cache contacts W/System.err: at io.rx_cache.internal.ProcessorProvidersBehaviour$6.call(ProcessorProvidersBehaviour.java:156) W/System.err: at rx.internal.operators.OperatorOnErrorResumeNextViaFunction$1.call(OperatorOnErrorResumeNextViaFunction.java:53) W/System.err: at rx.internal.operators.OperatorOnErrorResumeNextViaFunction$1.call(OperatorOnErrorResumeNextViaFunction.java:50) W/System.err: at rx.internal.operators.OperatorOnErrorResumeNextViaFunction$4.onError(OperatorOnErrorResumeNextViaFunction.java:140) W/System.err: at rx.internal.operators.OnSubscribeMap$MapSubscriber.onError(OnSubscribeMap.java:88) W/System.err: at retrofit2.adapter.rxjava.OperatorMapResponseToBodyOrError$1.onError(OperatorMapResponseToBodyOrError.java:52) W/System.err: at retrofit2.adapter.rxjava.RxJavaCallAdapterFactory$RequestArbiter.request(RxJavaCallAdapterFactory.java:178) W/System.err: at rx.internal.producers.ProducerArbiter.setProducer(ProducerArbiter.java:126) W/System.err: at rx.internal.operators.OperatorOnErrorResumeNextViaFunction$4.setProducer(OperatorOnErrorResumeNextViaFunction.java:159) W/System.err: at rx.internal.operators.OnSubscribeMap$MapSubscriber.setProducer(OnSubscribeMap.java:102) W/System.err: at rx.Subscriber.setProducer(Subscriber.java:205) W/System.err: at retrofit2.adapter.rxjava.RxJavaCallAdapterFactory$CallOnSubscribe.call(RxJavaCallAdapterFactory.java:152) W/System.err: at retrofit2.adapter.rxjava.RxJavaCallAdapterFactory$CallOnSubscribe.call(RxJavaCallAdapterFactory.java:138) W/System.err: at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) W/System.err: at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) W/System.err: at rx.Observable.unsafeSubscribe(Observable.java:10200) W/System.err: at rx.internal.operators.OnSubscribeMap.call(OnSubscribeMap.java:48) W/System.err: at rx.internal.operators.OnSubscribeMap.call(OnSubscribeMap.java:33) W/System.err: at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) W/System.err: at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) W/System.err: at rx.Observable.unsafeSubscribe(Observable.java:10200) W/System.err: at rx.internal.operators.OnSubscribeMap.call(OnSubscribeMap.java:48) W/System.err: at rx.internal.operators.OnSubscribeMap.call(OnSubscribeMap.java:33) W/System.err: at rx.Observable.unsafeSubscribe(Observable.java:10200) W/System.err: at rx.internal.operators.OperatorMerge$MergeSubscriber.onNext(OperatorMerge.java:248) W/System.err: at rx.internal.operators.OperatorMerge$MergeSubscriber.onNext(OperatorMerge.java:148) W/System.err: at rx.internal.operators.OnSubscribeMap$MapSubscriber.onNext(OnSubscribeMap.java:77) W/System.err: at rx.internal.operators.OnSubscribeMap$MapSubscriber.onNext(OnSubscribeMap.java:77) W/System.err: at rx.internal.util.ScalarSynchronousObservable$WeakSingleProducer.request(ScalarSynchronousObservable.java:276) W/System.err: at rx.Subscriber.setProducer(Subscriber.java:211) W/System.err: at rx.internal.operators.OnSubscribeMap$MapSubscriber.setProducer(OnSubscribeMap.java:102) W/System.err: at rx.internal.operators.OnSubscribeMap$MapSubscriber.setProducer(OnSubscribeMap.java:102) W/System.err: at rx.internal.util.ScalarSynchronousObservable$JustOnSubscribe.call(ScalarSynchronousObservable.java:138) W/System.err: at rx.internal.util.ScalarSynchronousObservable$JustOnSubscribe.call(ScalarSynchronousObservable.java:129) W/System.err: at rx.Observable.unsafeSubscribe(Observable.java:10200) W/System.err: at rx.internal.operators.OnSubscribeMap.call(OnSubscribeMap.java:48) W/System.err: at rx.internal.operators.OnSubscribeMap.call(OnSubscribeMap.java:33) W/System.err: at rx.Observable.unsafeSubscribe(Observable.java:10200) W/System.err: at rx.internal.operators.OnSubscribeMap.call(OnSubscribeMap.java:48) W/System.err: at rx.internal.operators.OnSubscribeMap.call(OnSubscribeMap.java:33) W/System.err: at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) W/System.err: at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) W/System.err: at rx.Observable.unsafeSubscribe(Observable.java:10200) W/System.err: at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:51) W/System.err: at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:35) W/System.err: at rx.Observable.unsafeSubscribe(Observable.java:10200) W/System.err: at rx.internal.operators.OperatorSubscribeOn$1.call(OperatorSubscribeOn.java:94) W/System.err: at rx.internal.schedulers.ScheduledAction.run(ScheduledAction.java:55) W/System.err: at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:442) W/System.err: at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305) W/System.err: at java.util.concurrent.FutureTask.run(FutureTask.java:137) W/System.err: at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:150) W/System.err: at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:264) W/System.err: at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076) W/System.err: at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569) W/System.err: at java.lang.Thread.run(Thread.java:856) W/System.err: Caused by: java.net.UnknownHostException: Unable to resolve host

[VictorAlbertos]

In order to show previous cached data, first, there should be data cached, and second, you need to use useExpiredDataWhenNoLoaderAvailable, as you already told me that you are using.

Be sure that there is already cached data, otherwise you will get that exception.

[arkantos1482]

I get the sameException.
It seems useExpiredDataWhenNoLoaderAvailable doesn't work.
Everything works until data get expired, after that I receive RxCacheException. (when i check the state of ReactiveCache instance, before expiration there were a record in ReferenceMemoryMap and Disk, but after expiration, those were vanished)

The code:
customerProvider = new ReactiveCache.Builder() .useExpiredDataWhenNoLoaderAvailable() .diskCacheSize(5) .using(context.getCacheDir(), new GsonSpeaker()) .<Customer>provider() .lifeCache(15, TimeUnit.SECONDS) .withKey("CUSTOMER");

getCustomerApi.compose(customerProvider.readWithLoader());