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.subscribers; import java.util.concurrent.CountDownLatch; import org.reactivestreams.Subscription; import io.reactivex.FlowableSubscriber; import io.reactivex.internal.subscriptions.SubscriptionHelper; import io.reactivex.internal.util.*; public abstract class BlockingBaseSubscriber<T> extends CountDownLatch implements FlowableSubscriber<T> { T value; Throwable error; Subscription upstream; volatile boolean cancelled; public BlockingBaseSubscriber() { super(1); } @Override public final void onSubscribe(Subscription s) { if (SubscriptionHelper.validate(this.upstream, s)) { this.upstream = s; if (!cancelled) { s.request(Long.MAX_VALUE); if (cancelled) { this.upstream = SubscriptionHelper.CANCELLED; s.cancel(); } } } } @Override public final void onComplete() { countDown(); }
Block until the first value arrives and return it, otherwise return null for an empty source and rethrow any exception.
Returns:the first value or null if the source is empty
/** * Block until the first value arrives and return it, otherwise * return null for an empty source and rethrow any exception. * @return the first value or null if the source is empty */
public final T blockingGet() { if (getCount() != 0) { try { BlockingHelper.verifyNonBlocking(); await(); } catch (InterruptedException ex) { Subscription s = this.upstream; this.upstream = SubscriptionHelper.CANCELLED; if (s != null) { s.cancel(); } throw ExceptionHelper.wrapOrThrow(ex); } } Throwable e = error; if (e != null) { throw ExceptionHelper.wrapOrThrow(e); } return value; } }