Skip to content

Instantly share code, notes, and snippets.

Embed
What would you like to do?
/**
* 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.subscriptions;
import java.util.concurrent.atomic.AtomicReference;
import rx.Observable;
import rx.Subscription;
/**
* Subscription that can be checked for status such as in a loop inside an {@link Observable} to exit the loop if unsubscribed.
*
* @see <a href="http://msdn.microsoft.com/en-us/library/system.reactive.disposables.multipleassignmentdisposable">Rx.Net equivalent MultipleAssignmentDisposable</a>
*/
public final class MultipleAssignmentSubscription implements Subscription {
private static final State EMPTY = new State(false, Subscriptions.empty());
private static final State DONE = new State(true, Subscriptions.empty());
private final AtomicReference<State> state = new AtomicReference<State>(EMPTY);
private static final class State {
final boolean isUnsubscribed;
final Subscription subscription;
State(boolean u, Subscription s) {
this.isUnsubscribed = u;
this.subscription = s;
}
State set(Subscription s) {
return new State(isUnsubscribed, s);
}
}
@Override
public boolean isUnsubscribed() {
return state.get().isUnsubscribed;
}
@Override
public void unsubscribe() {
terminate(true);
}
@Deprecated
public void setSubscription(Subscription s) {
set(s);
}
public void set(Subscription s) {
write(s, true);
}
/**
* Sets the subscription but does not unsubscribe it when set on a terminated instance.
* @param s the new subscription to attempt to set
* @param unsubscribeOld unsubscribe s if the current instance is already terminated?
*/
public void write(Subscription s, boolean unsubscribeOld) {
if (s == null) {
throw new IllegalArgumentException("Subscription can not be null");
}
State oldState;
State newState;
do {
oldState = state.get();
if (oldState.isUnsubscribed) {
if (unsubscribeOld) {
s.unsubscribe();
}
return;
} else {
newState = oldState.set(s);
}
} while (!state.compareAndSet(oldState, newState));
}
/**
* Terminate this subscription without unsubscribing from the current content.
* @param unsubscribeOld unsubscribe the inner instance?
*/
public void terminate(boolean unsubscribeOld) {
State oldState = state.getAndSet(DONE);
if (unsubscribeOld) {
oldState.subscription.unsubscribe();
}
}
@Deprecated
public Subscription getSubscription() {
return get();
}
public Subscription get() {
return state.get().subscription;
}
}
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment