LiveData + Rx(Hot observable Firebase) problem [Arquitecture question]
0
LiveData Rx Hot observable problem [Arquitecture question]
I have a question over transformation rx Publisher to livedata, I've been programed a project that using firebase rx livedata in a example.
The problem is that when converting a Publisher to LiveData, with LiveDataReactiveStreams library, when the subscription is inactive, the converter clear subscription and when state active create a new subscription.
Code
/**
* Defines a {@link LiveData} object that wraps a {@link Publisher}.
*
* <p>
* When the LiveData becomes active, it subscribes to the emissions from the Publisher.
*
* <p>
* When the LiveData becomes inactive, the subscription is cleared.
* LiveData holds the last value emitted by the Publisher when the LiveData was active.
* <p>
* Therefore, in the case of a hot RxJava Observable, when a new LiveData {@link Observer} is
* added, it will automatically notify with the last value held in LiveData,
* which might not be the last value emitted by the Publisher.
*
* <p>
* Note that LiveData does NOT handle errors and it expects that errors are treated as states
* in the data that's held. In case of an error being emitted by the publisher, an error will
* be propagated to the main thread and the app will crash.
*
* @param <T> The type of data hold by this instance.
*/
private static class PublisherLiveData<T> extends LiveData<T> {
private final Publisher<T> mPublisher;
final AtomicReference<LiveDataSubscriber> mSubscriber;
PublisherLiveData(@NonNull Publisher<T> publisher) {
mPublisher = publisher;
mSubscriber = new AtomicReference<>();
}
@Override
protected void onActive() { // Problem
super.onActive();
LiveDataSubscriber s = new LiveDataSubscriber();
mSubscriber.set(s);
mPublisher.subscribe(s);
}
@Override
protected void onInactive() { // Problem
super.onInactive();
LiveDataSubscriber s = mSubscriber.getAndSet(null);
if (s != null) {
s.cancelSubscription();
}
}
final class LiveDataSubscriber extends AtomicReference<Subscription>
implements Subscriber<T> {
@Override
public void onSubscribe(Subscription s) {
if (compareAndSet(null, s)) {
s.request(Long.MAX_VALUE);
} else {
s.cancel();
}
}
@Override
public void onNext(T item) {
postValue(item);
}
@Override
public void onError(final Throwable ex) {
mSubscriber.compareAndSet(this, null);
ArchTaskExecutor.getInstance().executeOnMainThread(new Runnable() {
@Override
public void run() {
// Errors should be handled upstream, so propagate as a crash.
throw new RuntimeException("LiveData does not handle errors. Errors from "
+ "publishers should be handled upstream and propagated as "
+ "state", ex);
}
});
}
@Override
public void onComplete() {
mSubscriber.compareAndSet(this, null);
}
public void cancelSubscription() {
Subscription s = get();
if (s != null) {
s.cancel();
}
}
}
}
In this class I add a boolen for decide if that has to subscribe or not
class CustomPublisherLiveData<T> extends LiveData<T> {
private boolean mResubscribe;
private final Publisher<T> mPublisher;
private final AtomicReference<LiveDataSubscriber> mSubscriber;
CustomPublisherLiveData(@NonNull Publisher<T> publisher, boolean resubscribe) {
mPublisher = publisher;
mResubscribe = resubscribe;
mSubscriber = new AtomicReference<>();
}
@Override
protected void onActive() {
super.onActive();
if (mResubscribe){
LiveDataSubscriber s = new LiveDataSubscriber();
mSubscriber.set(s);
mPublisher.subscribe(s);
}
}
@Override
protected void onInactive() {
super.onInactive();
LiveDataSubscriber s = mSubscriber.getAndSet(null);
if (s != null && mResubscribe) {
s.cancelSubscription();
}
}
final class LiveDataSubscriber extends AtomicReference<Subscription>
implements Subscriber<T> {
@Override
public void onSubscribe(Subscription s) {
if (compareAndSet(null, s)) {
s.request(Long.MAX_VALUE);
} else {
s.cancel();
}
}
@Override
public void onNext(T item) {
postValue(item);
}
@Override
public void onError(final Throwable ex) {
mSubscriber.compareAndSet(this, null);
//TODO silence error I have to make the error go up to the main thread
throw new RuntimeException("LiveData does not handle errors. Errors from "
+ "publishers should be handled upstream and propagated as "
+ "state", ex);
ArchTaskExecutor.getInstance().executeOnMainThread(new Runnable() {
@Override
public void run() {
// Errors should be handled upstream, so propagate as a crash.
throw new RuntimeException("LiveData does not handle errors. Errors from "
+ "publishers should be handled upstream and propagated as "
+ "state", ex);
}
});
}
@Override
public void onComplete() {
mSubscriber.compareAndSet(this, null);
}
public void cancelSubscription() {
Subscription s = get();
if (s != null) {
s.cancel();
}
}
}
Is this correct?
I must change the "livedata convert" or I'm missing something
I can a subscribe in a viewModel and set value in a new MutableLiveData but this create a more boilerplate code and i dont know is safe
Regards
android rx-java2 rx-kotlin2 livedata asked Dec 28 '18 at 13:01
Cristian M.GCristian M.G
212
add a comment |
0
LiveData Rx Hot observable problem [Arquitecture question]
I have a question over transformation rx Publisher to livedata, I've been programed a project that using firebase rx livedata in a example.
The problem is that when converting a Publisher to LiveData, with LiveDataReactiveStreams library, when the subscription is inactive, the converter clear subscription and when state active create a new subscription.
Code
/**
* Defines a {@link LiveData} object that wraps a {@link Publisher}.
*
* <p>
* When the LiveData becomes active, it subscribes to the emissions from the Publisher.
*
* <p>
* When the LiveData becomes inactive, the subscription is cleared.
* LiveData holds the last value emitted by the Publisher when the LiveData was active.
* <p>
* Therefore, in the case of a hot RxJava Observable, when a new LiveData {@link Observer} is
* added, it will automatically notify with the last value held in LiveData,
* which might not be the last value emitted by the Publisher.
*
* <p>
* Note that LiveData does NOT handle errors and it expects that errors are treated as states
* in the data that's held. In case of an error being emitted by the publisher, an error will
* be propagated to the main thread and the app will crash.
*
* @param <T> The type of data hold by this instance.
*/
private static class PublisherLiveData<T> extends LiveData<T> {
private final Publisher<T> mPublisher;
final AtomicReference<LiveDataSubscriber> mSubscriber;
PublisherLiveData(@NonNull Publisher<T> publisher) {
mPublisher = publisher;
mSubscriber = new AtomicReference<>();
}
@Override
protected void onActive() { // Problem
super.onActive();
LiveDataSubscriber s = new LiveDataSubscriber();
mSubscriber.set(s);
mPublisher.subscribe(s);
}
@Override
protected void onInactive() { // Problem
super.onInactive();
LiveDataSubscriber s = mSubscriber.getAndSet(null);
if (s != null) {
s.cancelSubscription();
}
}
final class LiveDataSubscriber extends AtomicReference<Subscription>
implements Subscriber<T> {
@Override
public void onSubscribe(Subscription s) {
if (compareAndSet(null, s)) {
s.request(Long.MAX_VALUE);
} else {
s.cancel();
}
}
@Override
public void onNext(T item) {
postValue(item);
}
@Override
public void onError(final Throwable ex) {
mSubscriber.compareAndSet(this, null);
ArchTaskExecutor.getInstance().executeOnMainThread(new Runnable() {
@Override
public void run() {
// Errors should be handled upstream, so propagate as a crash.
throw new RuntimeException("LiveData does not handle errors. Errors from "
+ "publishers should be handled upstream and propagated as "
+ "state", ex);
}
});
}
@Override
public void onComplete() {
mSubscriber.compareAndSet(this, null);
}
public void cancelSubscription() {
Subscription s = get();
if (s != null) {
s.cancel();
}
}
}
}
In this class I add a boolen for decide if that has to subscribe or not
class CustomPublisherLiveData<T> extends LiveData<T> {
private boolean mResubscribe;
private final Publisher<T> mPublisher;
private final AtomicReference<LiveDataSubscriber> mSubscriber;
CustomPublisherLiveData(@NonNull Publisher<T> publisher, boolean resubscribe) {
mPublisher = publisher;
mResubscribe = resubscribe;
mSubscriber = new AtomicReference<>();
}
@Override
protected void onActive() {
super.onActive();
if (mResubscribe){
LiveDataSubscriber s = new LiveDataSubscriber();
mSubscriber.set(s);
mPublisher.subscribe(s);
}
}
@Override
protected void onInactive() {
super.onInactive();
LiveDataSubscriber s = mSubscriber.getAndSet(null);
if (s != null && mResubscribe) {
s.cancelSubscription();
}
}
final class LiveDataSubscriber extends AtomicReference<Subscription>
implements Subscriber<T> {
@Override
public void onSubscribe(Subscription s) {
if (compareAndSet(null, s)) {
s.request(Long.MAX_VALUE);
} else {
s.cancel();
}
}
@Override
public void onNext(T item) {
postValue(item);
}
@Override
public void onError(final Throwable ex) {
mSubscriber.compareAndSet(this, null);
//TODO silence error I have to make the error go up to the main thread
throw new RuntimeException("LiveData does not handle errors. Errors from "
+ "publishers should be handled upstream and propagated as "
+ "state", ex);
ArchTaskExecutor.getInstance().executeOnMainThread(new Runnable() {
@Override
public void run() {
// Errors should be handled upstream, so propagate as a crash.
throw new RuntimeException("LiveData does not handle errors. Errors from "
+ "publishers should be handled upstream and propagated as "
+ "state", ex);
}
});
}
@Override
public void onComplete() {
mSubscriber.compareAndSet(this, null);
}
public void cancelSubscription() {
Subscription s = get();
if (s != null) {
s.cancel();
}
}
}
Is this correct?
I must change the "livedata convert" or I'm missing something
I can a subscribe in a viewModel and set value in a new MutableLiveData but this create a more boilerplate code and i dont know is safe
Regards
android rx-java2 rx-kotlin2 livedata asked Dec 28 '18 at 13:01
Cristian M.GCristian M.G
212
add a comment |
0
0
0
LiveData Rx Hot observable problem [Arquitecture question]
I have a question over transformation rx Publisher to livedata, I've been programed a project that using firebase rx livedata in a example.
The problem is that when converting a Publisher to LiveData, with LiveDataReactiveStreams library, when the subscription is inactive, the converter clear subscription and when state active create a new subscription.
Code
/**
* Defines a {@link LiveData} object that wraps a {@link Publisher}.
*
* <p>
* When the LiveData becomes active, it subscribes to the emissions from the Publisher.
*
* <p>
* When the LiveData becomes inactive, the subscription is cleared.
* LiveData holds the last value emitted by the Publisher when the LiveData was active.
* <p>
* Therefore, in the case of a hot RxJava Observable, when a new LiveData {@link Observer} is
* added, it will automatically notify with the last value held in LiveData,
* which might not be the last value emitted by the Publisher.
*
* <p>
* Note that LiveData does NOT handle errors and it expects that errors are treated as states
* in the data that's held. In case of an error being emitted by the publisher, an error will
* be propagated to the main thread and the app will crash.
*
* @param <T> The type of data hold by this instance.
*/
private static class PublisherLiveData<T> extends LiveData<T> {
private final Publisher<T> mPublisher;
final AtomicReference<LiveDataSubscriber> mSubscriber;
PublisherLiveData(@NonNull Publisher<T> publisher) {
mPublisher = publisher;
mSubscriber = new AtomicReference<>();
}
@Override
protected void onActive() { // Problem
super.onActive();
LiveDataSubscriber s = new LiveDataSubscriber();
mSubscriber.set(s);
mPublisher.subscribe(s);
}
@Override
protected void onInactive() { // Problem
super.onInactive();
LiveDataSubscriber s = mSubscriber.getAndSet(null);
if (s != null) {
s.cancelSubscription();
}
}
final class LiveDataSubscriber extends AtomicReference<Subscription>
implements Subscriber<T> {
@Override
public void onSubscribe(Subscription s) {
if (compareAndSet(null, s)) {
s.request(Long.MAX_VALUE);
} else {
s.cancel();
}
}
@Override
public void onNext(T item) {
postValue(item);
}
@Override
public void onError(final Throwable ex) {
mSubscriber.compareAndSet(this, null);
ArchTaskExecutor.getInstance().executeOnMainThread(new Runnable() {
@Override
public void run() {
// Errors should be handled upstream, so propagate as a crash.
throw new RuntimeException("LiveData does not handle errors. Errors from "
+ "publishers should be handled upstream and propagated as "
+ "state", ex);
}
});
}
@Override
public void onComplete() {
mSubscriber.compareAndSet(this, null);
}
public void cancelSubscription() {
Subscription s = get();
if (s != null) {
s.cancel();
}
}
}
}
In this class I add a boolen for decide if that has to subscribe or not
class CustomPublisherLiveData<T> extends LiveData<T> {
private boolean mResubscribe;
private final Publisher<T> mPublisher;
private final AtomicReference<LiveDataSubscriber> mSubscriber;
CustomPublisherLiveData(@NonNull Publisher<T> publisher, boolean resubscribe) {
mPublisher = publisher;
mResubscribe = resubscribe;
mSubscriber = new AtomicReference<>();
}
@Override
protected void onActive() {
super.onActive();
if (mResubscribe){
LiveDataSubscriber s = new LiveDataSubscriber();
mSubscriber.set(s);
mPublisher.subscribe(s);
}
}
@Override
protected void onInactive() {
super.onInactive();
LiveDataSubscriber s = mSubscriber.getAndSet(null);
if (s != null && mResubscribe) {
s.cancelSubscription();
}
}
final class LiveDataSubscriber extends AtomicReference<Subscription>
implements Subscriber<T> {
@Override
public void onSubscribe(Subscription s) {
if (compareAndSet(null, s)) {
s.request(Long.MAX_VALUE);
} else {
s.cancel();
}
}
@Override
public void onNext(T item) {
postValue(item);
}
@Override
public void onError(final Throwable ex) {
mSubscriber.compareAndSet(this, null);
//TODO silence error I have to make the error go up to the main thread
throw new RuntimeException("LiveData does not handle errors. Errors from "
+ "publishers should be handled upstream and propagated as "
+ "state", ex);
ArchTaskExecutor.getInstance().executeOnMainThread(new Runnable() {
@Override
public void run() {
// Errors should be handled upstream, so propagate as a crash.
throw new RuntimeException("LiveData does not handle errors. Errors from "
+ "publishers should be handled upstream and propagated as "
+ "state", ex);
}
});
}
@Override
public void onComplete() {
mSubscriber.compareAndSet(this, null);
}
public void cancelSubscription() {
Subscription s = get();
if (s != null) {
s.cancel();
}
}
}
Is this correct?
I must change the "livedata convert" or I'm missing something
I can a subscribe in a viewModel and set value in a new MutableLiveData but this create a more boilerplate code and i dont know is safe
Regards
android rx-java2 rx-kotlin2 livedata asked Dec 28 '18 at 13:01
Cristian M.GCristian M.G
212
LiveData Rx Hot observable problem [Arquitecture question]
I have a question over transformation rx Publisher to livedata, I've been programed a project that using firebase rx livedata in a example.
The problem is that when converting a Publisher to LiveData, with LiveDataReactiveStreams library, when the subscription is inactive, the converter clear subscription and when state active create a new subscription.
Code
/**
* Defines a {@link LiveData} object that wraps a {@link Publisher}.
*
* <p>
* When the LiveData becomes active, it subscribes to the emissions from the Publisher.
*
* <p>
* When the LiveData becomes inactive, the subscription is cleared.
* LiveData holds the last value emitted by the Publisher when the LiveData was active.
* <p>
* Therefore, in the case of a hot RxJava Observable, when a new LiveData {@link Observer} is
* added, it will automatically notify with the last value held in LiveData,
* which might not be the last value emitted by the Publisher.
*
* <p>
* Note that LiveData does NOT handle errors and it expects that errors are treated as states
* in the data that's held. In case of an error being emitted by the publisher, an error will
* be propagated to the main thread and the app will crash.
*
* @param <T> The type of data hold by this instance.
*/
private static class PublisherLiveData<T> extends LiveData<T> {
private final Publisher<T> mPublisher;
final AtomicReference<LiveDataSubscriber> mSubscriber;
PublisherLiveData(@NonNull Publisher<T> publisher) {
mPublisher = publisher;
mSubscriber = new AtomicReference<>();
}
@Override
protected void onActive() { // Problem
super.onActive();
LiveDataSubscriber s = new LiveDataSubscriber();
mSubscriber.set(s);
mPublisher.subscribe(s);
}
@Override
protected void onInactive() { // Problem
super.onInactive();
LiveDataSubscriber s = mSubscriber.getAndSet(null);
if (s != null) {
s.cancelSubscription();
}
}
final class LiveDataSubscriber extends AtomicReference<Subscription>
implements Subscriber<T> {
@Override
public void onSubscribe(Subscription s) {
if (compareAndSet(null, s)) {
s.request(Long.MAX_VALUE);
} else {
s.cancel();
}
}
@Override
public void onNext(T item) {
postValue(item);
}
@Override
public void onError(final Throwable ex) {
mSubscriber.compareAndSet(this, null);
ArchTaskExecutor.getInstance().executeOnMainThread(new Runnable() {
@Override
public void run() {
// Errors should be handled upstream, so propagate as a crash.
throw new RuntimeException("LiveData does not handle errors. Errors from "
+ "publishers should be handled upstream and propagated as "
+ "state", ex);
}
});
}
@Override
public void onComplete() {
mSubscriber.compareAndSet(this, null);
}
public void cancelSubscription() {
Subscription s = get();
if (s != null) {
s.cancel();
}
}
}
}
In this class I add a boolen for decide if that has to subscribe or not
class CustomPublisherLiveData<T> extends LiveData<T> {
private boolean mResubscribe;
private final Publisher<T> mPublisher;
private final AtomicReference<LiveDataSubscriber> mSubscriber;
CustomPublisherLiveData(@NonNull Publisher<T> publisher, boolean resubscribe) {
mPublisher = publisher;
mResubscribe = resubscribe;
mSubscriber = new AtomicReference<>();
}
@Override
protected void onActive() {
super.onActive();
if (mResubscribe){
LiveDataSubscriber s = new LiveDataSubscriber();
mSubscriber.set(s);
mPublisher.subscribe(s);
}
}
@Override
protected void onInactive() {
super.onInactive();
LiveDataSubscriber s = mSubscriber.getAndSet(null);
if (s != null && mResubscribe) {
s.cancelSubscription();
}
}
final class LiveDataSubscriber extends AtomicReference<Subscription>
implements Subscriber<T> {
@Override
public void onSubscribe(Subscription s) {
if (compareAndSet(null, s)) {
s.request(Long.MAX_VALUE);
} else {
s.cancel();
}
}
@Override
public void onNext(T item) {
postValue(item);
}
@Override
public void onError(final Throwable ex) {
mSubscriber.compareAndSet(this, null);
//TODO silence error I have to make the error go up to the main thread
throw new RuntimeException("LiveData does not handle errors. Errors from "
+ "publishers should be handled upstream and propagated as "
+ "state", ex);
ArchTaskExecutor.getInstance().executeOnMainThread(new Runnable() {
@Override
public void run() {
// Errors should be handled upstream, so propagate as a crash.
throw new RuntimeException("LiveData does not handle errors. Errors from "
+ "publishers should be handled upstream and propagated as "
+ "state", ex);
}
});
}
@Override
public void onComplete() {
mSubscriber.compareAndSet(this, null);
}
public void cancelSubscription() {
Subscription s = get();
if (s != null) {
s.cancel();
}
}
}
Is this correct?
I must change the "livedata convert" or I'm missing something
I can a subscribe in a viewModel and set value in a new MutableLiveData but this create a more boilerplate code and i dont know is safe
Regards
android rx-java2 rx-kotlin2 livedata android rx-java2 rx-kotlin2 livedata asked Dec 28 '18 at 13:01
Cristian M.GCristian M.G
212
asked Dec 28 '18 at 13:01
Cristian M.GCristian M.G
212
asked Dec 28 '18 at 13:01
Cristian M.GCristian M.G
212
asked Dec 28 '18 at 13:01
Cristian M.GCristian M.G
212
asked Dec 28 '18 at 13:01
Cristian M.GCristian M.G
212
212
add a comment |
add a comment |
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