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/**
* Copyright 2014 Netflix, Inc.
*
* 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 rx.subjects;
import rx.Subscriber;
import rx.observers.SerializedObserver;
/**
* Wraps a {@link Subject} so that it is safe to call its various {@code on} methods from different threads.
*
* When you use an ordinary {@link Subject} as a {@link Subscriber}, you must take care not to call its
* {@link Subscriber#onNext} method (or its other {@code on} methods) from multiple threads, as this could lead
* to non-serialized calls, which violates the
* Observable contract and creates an ambiguity in the resulting Subject.
*
* To protect a {@code Subject} from this danger, you can convert it into a {@code SerializedSubject} with code
* like the following:
*
{@code
* mySafeSubject = new SerializedSubject( myUnsafeSubject );
* }
*
* @param the input value type
* @param the output value type
*/
public class SerializedSubject extends Subject {
private final SerializedObserver observer;
private final Subject actual;
public SerializedSubject(final Subject actual) {
super(new OnSubscribe() {
@Override
public void call(Subscriber child) {
actual.unsafeSubscribe(child);
}
});
this.actual = actual;
this.observer = new SerializedObserver(actual);
}
@Override
public void onCompleted() {
observer.onCompleted();
}
@Override
public void onError(Throwable e) {
observer.onError(e);
}
@Override
public void onNext(T t) {
observer.onNext(t);
}
@Override
public boolean hasObservers() {
return actual.hasObservers();
}
}