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package cgeo.geocaching.utils;
import rx.Observable;
import rx.Observable.OnSubscribe;
import rx.Scheduler;
import rx.Scheduler.Worker;
import rx.Subscriber;
import rx.android.schedulers.AndroidSchedulers;
import rx.functions.Action0;
import rx.functions.Action1;
import rx.functions.Func0;
import rx.functions.Func1;
import rx.internal.util.RxThreadFactory;
import rx.observables.BlockingObservable;
import rx.observers.Subscribers;
import rx.schedulers.Schedulers;
import rx.subjects.PublishSubject;
import rx.subscriptions.Subscriptions;
import android.os.Handler;
import android.os.HandlerThread;
import android.os.Looper;
import android.os.Process;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicReference;
public class RxUtils {
private RxUtils() {
// Utility class, not to be instantiated
}
public final static Scheduler computationScheduler = Schedulers.computation();
public static final Scheduler networkScheduler = Schedulers.from(Executors.newFixedThreadPool(10, new RxThreadFactory("network-")));
public static final Scheduler refreshScheduler = Schedulers.from(Executors.newFixedThreadPool(3, new RxThreadFactory("refresh-")));
private static final HandlerThread looperCallbacksThread =
new HandlerThread("looper callbacks", Process.THREAD_PRIORITY_DEFAULT);
static {
looperCallbacksThread.start();
}
public static final Looper looperCallbacksLooper = looperCallbacksThread.getLooper();
public static final Scheduler looperCallbacksScheduler = AndroidSchedulers.handlerThread(new Handler(looperCallbacksLooper));
public static final Worker looperCallbacksWorker = looperCallbacksScheduler.createWorker();
public static <T> void waitForCompletion(final BlockingObservable<T> observable) {
observable.lastOrDefault(null);
}
public static void waitForCompletion(final Observable<?>... observables) {
waitForCompletion(Observable.merge(observables).toBlocking());
}
/**
* Subscribe function whose subscription and unsubscription take place on a looper thread.
*
* @param <T>
* the type of the observable
*/
public static abstract class LooperCallbacks<T> implements OnSubscribe<T> {
final AtomicInteger counter = new AtomicInteger(0);
final long stopDelay;
final TimeUnit stopDelayUnit;
final protected PublishSubject<T> subject = PublishSubject.create();
public LooperCallbacks(final long stopDelay, final TimeUnit stopDelayUnit) {
this.stopDelay = stopDelay;
this.stopDelayUnit = stopDelayUnit;
}
public LooperCallbacks() {
this(0, TimeUnit.SECONDS);
}
@Override
final public void call(final Subscriber<? super T> subscriber) {
subscriber.add(subject.subscribe(Subscribers.from(subscriber)));
looperCallbacksWorker.schedule(new Action0() {
@Override
public void call() {
if (counter.getAndIncrement() == 0) {
onStart();
}
subscriber.add(Subscriptions.create(new Action0() {
@Override
public void call() {
looperCallbacksWorker.schedule(new Action0() {
@Override
public void call() {
if (counter.decrementAndGet() == 0) {
onStop();
}
}
}, stopDelay, stopDelayUnit);
}
}));
}
});
}
abstract protected void onStart();
abstract protected void onStop();
}
public static<T> Observable<T> rememberLast(final Observable<T> observable, final T initialValue) {
final AtomicReference<T> lastValue = new AtomicReference<>(initialValue);
return observable.doOnNext(new Action1<T>() {
@Override
public void call(final T value) {
lastValue.set(value);
}
}).startWith(Observable.defer(new Func0<Observable<T>>() {
@Override
public Observable<T> call() {
final T last = lastValue.get();
return last != null ? Observable.just(last) : Observable.<T>empty();
}
})).replay(1).refCount();
}
public static <T> void andThenOnUi(final Scheduler scheduler, final Func0<T> background, final Action1<T> foreground) {
scheduler.createWorker().schedule(new Action0() {
@Override
public void call() {
final T value = background.call();
AndroidSchedulers.mainThread().createWorker().schedule(new Action0() {
@Override
public void call() {
foreground.call(value);
}
});
}
});
}
public static void andThenOnUi(final Scheduler scheduler, final Action0 background, final Action0 foreground) {
scheduler.createWorker().schedule(new Action0() {
@Override
public void call() {
background.call();
AndroidSchedulers.mainThread().createWorker().schedule(foreground);
}
});
}
/**
* Cache the last value of observables so that every key is associated to only one of them.
*
* @param <K> the type of the key
* @param <V> the type of the value
*/
public static class ObservableCache<K, V> {
final private Func1<K, Observable<V>> func;
final private Map<K, Observable<V>> cached = new HashMap<>();
/**
* Create a new observables cache.
*
* @param func the function transforming a key into an observable
*/
public ObservableCache(final Func1<K, Observable<V>> func) {
this.func = func;
}
/**
* Get the observable corresponding to a key. If the key has not already been
* seen, the function passed to the constructor will be called to build the observable
* <p/>
* If the observable has already emitted values, only the last one will be remembered.
*
* @param key the key
* @return the observable corresponding to the key
*/
public synchronized Observable<V> get(final K key) {
if (cached.containsKey(key)) {
return cached.get(key);
}
final Observable<V> value = func.call(key).replay(1).refCount();
cached.put(key, value);
return value;
}
}
}
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