/**
* 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.internal.operators;
import rx.Observable;
import rx.Observable.OnSubscribe;
import rx.Subscriber;
import rx.functions.Func0;
/**
* Do not create the Observable until an Observer subscribes; create a fresh Observable on each
* subscription.
* <p>
* <img width="640" src="https://github.com/Netflix/RxJava/wiki/images/rx-operators/defer.png" alt="">
* <p>
* Pass defer an Observable factory function (a function that generates Observables), and defer will
* return an Observable that will call this function to generate its Observable sequence afresh
* each time a new Observer subscribes.
*/
public final class OnSubscribeDefer<T> implements OnSubscribe<T> {
final Func0<? extends Observable<? extends T>> observableFactory;
public OnSubscribeDefer(Func0<? extends Observable<? extends T>> observableFactory) {
this.observableFactory = observableFactory;
}
@Override
public void call(Subscriber<? super T> s) {
Observable<? extends T> o;
try {
o = observableFactory.call();
} catch (Throwable t) {
s.onError(t);
return;
}
o.unsafeSubscribe(s);
}
}