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/**
* 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;
import rx.functions.Action0;
/**
* Subscription that can be checked for status such as in a loop inside an {@link Observable} to exit the loop
* if unsubscribed.
*/
public final class BooleanSubscription implements Subscription {
final AtomicReference actionRef;
public BooleanSubscription() {
actionRef = new AtomicReference();
}
private BooleanSubscription(Action0 action) {
actionRef = new AtomicReference(action);
}
/**
* Creates a {@code BooleanSubscription} without unsubscribe behavior.
*
* @return the created {@code BooleanSubscription}
*/
public static BooleanSubscription create() {
return new BooleanSubscription();
}
/**
* Creates a {@code BooleanSubscription} with a specified function to invoke upon unsubscribe.
*
* @param onUnsubscribe
* an {@link Action0} to invoke upon unsubscribe
* @return the created {@code BooleanSubscription}
*/
public static BooleanSubscription create(Action0 onUnsubscribe) {
return new BooleanSubscription(onUnsubscribe);
}
@Override
public boolean isUnsubscribed() {
return actionRef.get() == EMPTY_ACTION;
}
@Override
public void unsubscribe() {
Action0 action = actionRef.get();
if (action != EMPTY_ACTION) {
action = actionRef.getAndSet(EMPTY_ACTION);
if (action != null && action != EMPTY_ACTION) {
action.call();
}
}
}
static final Action0 EMPTY_ACTION = new Action0() {
@Override
public void call() {
// deliberately no-op
}
};
}