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/*
* Copyright 2016-2018 David Karnok
*
* 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 hu.akarnokd.rxjava2.subjects;
import io.reactivex.annotations.*;
import io.reactivex.internal.functions.ObjectHelper;
import io.reactivex.subjects.Subject;
/**
* Utility methods to work with RxJava 2 Subjects.
* @since 0.18.2
*/
public final class Subjects {
/** Utility class. */
private Subjects() {
throw new IllegalStateException("No instances!");
}
/**
* Wraps a Subject and makes sure if all observers dispose
* their disposables, the upstream's Disposable gets disposed as well.
*
* This operator is similar to {@link io.reactivex.observables.ConnectableObservable#refCount()}
* except the first Observer doesn't trigger any sort of connection; that happens
* when the resulting Subject is subscribed to an Observable manually.
* @param the input and output value type
* @param subject the subject to wrap, not null
* @return the wrapped and reference-counted Subject
* @since 2.1.8 - experimental
*/
@NonNull
@CheckReturnValue
public static Subject refCount(Subject subject) {
if (subject instanceof RefCountSubject) {
return subject;
}
return new RefCountSubject(ObjectHelper.requireNonNull(subject, "subject is null"));
}
}