Copyright (c) 2016-present, RxJava Contributors. Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
/** * Copyright (c) 2016-present, RxJava Contributors. * * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in * compliance with the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software distributed under the License is * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See * the License for the specific language governing permissions and limitations under the License. */
package io.reactivex.internal.operators.observable; import io.reactivex.*; import io.reactivex.disposables.Disposable; import io.reactivex.internal.disposables.DisposableHelper; import io.reactivex.internal.fuseable.FuseToObservable; import java.util.NoSuchElementException; import io.reactivex.plugins.RxJavaPlugins; public final class ObservableElementAtSingle<T> extends Single<T> implements FuseToObservable<T> { final ObservableSource<T> source; final long index; final T defaultValue; public ObservableElementAtSingle(ObservableSource<T> source, long index, T defaultValue) { this.source = source; this.index = index; this.defaultValue = defaultValue; } @Override public void subscribeActual(SingleObserver<? super T> t) { source.subscribe(new ElementAtObserver<T>(t, index, defaultValue)); } @Override public Observable<T> fuseToObservable() { return RxJavaPlugins.onAssembly(new ObservableElementAt<T>(source, index, defaultValue, true)); } static final class ElementAtObserver<T> implements Observer<T>, Disposable { final SingleObserver<? super T> downstream; final long index; final T defaultValue; Disposable upstream; long count; boolean done; ElementAtObserver(SingleObserver<? super T> actual, long index, T defaultValue) { this.downstream = actual; this.index = index; this.defaultValue = defaultValue; } @Override public void onSubscribe(Disposable d) { if (DisposableHelper.validate(this.upstream, d)) { this.upstream = d; downstream.onSubscribe(this); } } @Override public void dispose() { upstream.dispose(); } @Override public boolean isDisposed() { return upstream.isDisposed(); } @Override public void onNext(T t) { if (done) { return; } long c = count; if (c == index) { done = true; upstream.dispose(); downstream.onSuccess(t); return; } count = c + 1; } @Override public void onError(Throwable t) { if (done) { RxJavaPlugins.onError(t); return; } done = true; downstream.onError(t); } @Override public void onComplete() { if (!done) { done = true; T v = defaultValue; if (v != null) { downstream.onSuccess(v); } else { downstream.onError(new NoSuchElementException()); } } } } }