/**
* Copyright (c) 2016-present, RxJava Contributors.
*
* 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 io.reactivex.internal.observers;
import java.util.concurrent.
CountDownLatch;
import io.reactivex.
Observer;
import io.reactivex.disposables.
Disposable;
import io.reactivex.internal.util.*;
public abstract class
BlockingBaseObserver<T> extends
CountDownLatch
implements
Observer<T>,
Disposable {
T
value;
Throwable error;
Disposable upstream;
volatile boolean
cancelled;
public
BlockingBaseObserver() {
super(1);
}
@
Override
public final void
onSubscribe(
Disposable d) {
this.
upstream =
d;
if (
cancelled) {
d.
dispose();
}
}
@
Override
public final void
onComplete() {
countDown();
}
@
Override
public final void
dispose() {
cancelled = true;
Disposable d = this.
upstream;
if (
d != null) {
d.
dispose();
}
}
@
Override
public final boolean
isDisposed() {
return
cancelled;
}
/**
* Block until the first value arrives and return it, otherwise
* return null for an empty source and rethrow any exception.
* @return the first value or null if the source is empty
*/
public final T
blockingGet() {
if (
getCount() != 0) {
try {
BlockingHelper.
verifyNonBlocking();
await();
} catch (
InterruptedException ex) {
dispose();
throw
ExceptionHelper.
wrapOrThrow(
ex);
}
}
Throwable e =
error;
if (
e != null) {
throw
ExceptionHelper.
wrapOrThrow(
e);
}
return
value;
}
}