/**
* Copyright 2015 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.singles;
import java.util.concurrent.*;
import java.util.concurrent.atomic.
AtomicReference;
import rx.*;
import rx.exceptions.
Exceptions;
import rx.internal.operators.
BlockingOperatorToFuture;
import rx.internal.util.
BlockingUtils;
/**
* {@code BlockingSingle} is a blocking "version" of {@link Single} that provides blocking
* operators.
* <p/>
* You construct a {@code BlockingSingle} from a {@code Single} with {@link #from(Single)}
* or {@link Single#toBlocking()}.
*
* @param <T> the value type of the sequence
* @since 1.3
*/
public final class
BlockingSingle<T> {
private final
Single<? extends T>
single;
private
BlockingSingle(
Single<? extends T>
single) {
this.
single =
single;
}
/**
* Converts a {@link Single} into a {@code BlockingSingle}.
*
* @param <T> the value type of the sequence
* @param single the {@link Single} you want to convert
* @return a {@code BlockingSingle} version of {@code single}
*/
public static <T>
BlockingSingle<T>
from(
Single<? extends T>
single) {
return new
BlockingSingle<T>(
single);
}
/**
* Returns the item emitted by this {@code BlockingSingle}.
* <p/>
* If the underlying {@link Single} returns successfully, the value emitted
* by the {@link Single} is returned. If the {@link Single} emits an error,
* the throwable emitted ({@link SingleSubscriber#onError(Throwable)}) is
* thrown.
*
* @return the value emitted by this {@code BlockingSingle}
*/
public T
value() {
final
AtomicReference<T>
returnItem = new
AtomicReference<T>();
final
AtomicReference<
Throwable>
returnException = new
AtomicReference<
Throwable>();
final
CountDownLatch latch = new
CountDownLatch(1);
Subscription subscription =
single.
subscribe(new
SingleSubscriber<T>() {
@
Override
public void
onSuccess(T
value) {
returnItem.
set(
value);
latch.
countDown();
}
@
Override
public void
onError(
Throwable error) {
returnException.
set(
error);
latch.
countDown();
}
});
BlockingUtils.
awaitForComplete(
latch,
subscription);
Throwable throwable =
returnException.
get();
if (
throwable != null) {
throw
Exceptions.
propagate(
throwable);
}
return
returnItem.
get();
}
/**
* Returns a {@link Future} representing the value emitted by this {@code BlockingSingle}.
*
* @return a {@link Future} that returns the value
*/
@
SuppressWarnings("unchecked")
public
Future<T>
toFuture() {
return
BlockingOperatorToFuture.
toFuture(((
Single<T>)
single).
toObservable());
}
}