io.reactivex.internal.subscribers.DeferredScalarSubscriber Maven / Gradle / Ivy
/**
* 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 org.reactivestreams.*;
import io.reactivex.FlowableSubscriber;
import io.reactivex.internal.subscriptions.*;
/**
* A subscriber, extending a DeferredScalarSubscription,
* that is unbounded-in and can generate 0 or 1 resulting value.
* @param the input value type
* @param the output value type
*/
public abstract class DeferredScalarSubscriber extends DeferredScalarSubscription
implements FlowableSubscriber {
private static final long serialVersionUID = 2984505488220891551L;
/** The upstream subscription. */
protected Subscription s;
/** Can indicate if there was at least on onNext call. */
protected boolean hasValue;
/**
* Creates a DeferredScalarSubscriber instance and wraps a downstream Subscriber.
* @param actual the downstream subscriber, not null (not verified)
*/
public DeferredScalarSubscriber(Subscriber actual) {
super(actual);
}
@Override
public void onSubscribe(Subscription s) {
if (SubscriptionHelper.validate(this.s, s)) {
this.s = s;
actual.onSubscribe(this);
s.request(Long.MAX_VALUE);
}
}
@Override
public void onError(Throwable t) {
value = null;
actual.onError(t);
}
@Override
public void onComplete() {
if (hasValue) {
complete(value);
} else {
actual.onComplete();
}
}
@Override
public void cancel() {
super.cancel();
s.cancel();
}
}