/**

* 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.operators;

import java.util.concurrent.atomic.AtomicBoolean;

import rx.Observable;

import rx.Observable.OnSubscribeFunc;

import rx.Observer;

import rx.Subscription;

import rx.util.functions.Func1;

/**

* Returns an Observable that emits a Boolean that indicates whether all items emitted by an

* Observable satisfy a condition.

* <p>

* <img width="640" src="https://github.com/Netflix/RxJava/wiki/images/rx-operators/all.png">

*/

public class OperationAll {

public static <T> OnSubscribeFunc<Boolean> all(Observable<? extends T> sequence, Func1<? super T, Boolean> predicate) {

return new AllObservable<T>(sequence, predicate);

}

private static class AllObservable<T> implements OnSubscribeFunc<Boolean> {

private final Observable<? extends T> sequence;

private final Func1<? super T, Boolean> predicate;

private final SafeObservableSubscription subscription = new SafeObservableSubscription();

private AllObservable(Observable<? extends T> sequence, Func1<? super T, Boolean> predicate) {

this.sequence = sequence;

this.predicate = predicate;

}

@Override

public Subscription onSubscribe(final Observer<? super Boolean> observer) {

return subscription.wrap(sequence.subscribe(new AllObserver(observer)));

}

private class AllObserver implements Observer<T> {

private final Observer<? super Boolean> underlying;

private final AtomicBoolean status = new AtomicBoolean(true);

public AllObserver(Observer<? super Boolean> underlying) {

this.underlying = underlying;

}

@Override

public void onCompleted() {

if (status.get()) {

underlying.onNext(true);

underlying.onCompleted();

}

}

@Override

public void onError(Throwable e) {

underlying.onError(e);

}

@Override

public void onNext(T args) {

boolean result = predicate.call(args);

boolean changed = status.compareAndSet(true, result);

if (changed && !result) {

underlying.onNext(false);

underlying.onCompleted();

subscription.unsubscribe();

}

}

}

}

}