/**
* 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<
Action0>
actionRef;
public
BooleanSubscription() {
actionRef = new
AtomicReference<
Action0>();
}
private
BooleanSubscription(
Action0 action) {
actionRef = new
AtomicReference<
Action0>(
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
}
};
}