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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.internal.util;
import java.util.*;
import rx.Subscription;
import rx.exceptions.Exceptions;
/**
* Subscription that represents a group of Subscriptions that are unsubscribed together.
*
* @see Rx.Net equivalent CompositeDisposable
*/
public final class SubscriptionList implements Subscription {
private List subscriptions;
private volatile boolean unsubscribed;
/**
* Constructs an empty SubscriptionList.
*/
public SubscriptionList() {
// nothing to do
}
/**
* Constructs a SubscriptionList with the given initial child subscriptions.
* @param subscriptions the array of subscriptions to start with
*/
public SubscriptionList(final Subscription... subscriptions) {
this.subscriptions = new LinkedList(Arrays.asList(subscriptions));
}
/**
* Constructs a SubscriptionList with the given initial child subscription.
* @param s the initial subscription instance
*/
public SubscriptionList(Subscription s) {
this.subscriptions = new LinkedList();
this.subscriptions.add(s);
}
@Override
public boolean isUnsubscribed() {
return unsubscribed;
}
/**
* Adds a new {@link Subscription} to this {@code SubscriptionList} if the {@code SubscriptionList} is
* not yet unsubscribed. If the {@code SubscriptionList} is unsubscribed, {@code add} will
* indicate this by explicitly unsubscribing the new {@code Subscription} as well.
*
* @param s
* the {@link Subscription} to add
*/
public void add(final Subscription s) {
if (s.isUnsubscribed()) {
return;
}
if (!unsubscribed) {
synchronized (this) {
if (!unsubscribed) {
List subs = subscriptions;
if (subs == null) {
subs = new LinkedList();
subscriptions = subs;
}
subs.add(s);
return;
}
}
}
// call after leaving the synchronized block so we're not holding a lock while executing this
s.unsubscribe();
}
public void remove(final Subscription s) {
if (!unsubscribed) {
boolean unsubscribe;
synchronized (this) {
List subs = subscriptions;
if (unsubscribed || subs == null) {
return;
}
unsubscribe = subs.remove(s);
}
if (unsubscribe) {
// if we removed successfully we then need to call unsubscribe on it (outside of the lock)
s.unsubscribe();
}
}
}
/**
* Unsubscribe from all of the subscriptions in the list, which stops the receipt of notifications on
* the associated {@code Subscriber}.
*/
@Override
public void unsubscribe() {
if (!unsubscribed) {
List list;
synchronized (this) {
if (unsubscribed) {
return;
}
unsubscribed = true;
list = subscriptions;
subscriptions = null;
}
// we will only get here once
unsubscribeFromAll(list);
}
}
private static void unsubscribeFromAll(Collection subscriptions) {
if (subscriptions == null) {
return;
}
List es = null;
for (Subscription s : subscriptions) {
try {
s.unsubscribe();
} catch (Throwable e) {
if (es == null) {
es = new ArrayList();
}
es.add(e);
}
}
Exceptions.throwIfAny(es);
}
/* perf support */
public void clear() {
if (!unsubscribed) {
List list;
synchronized (this) {
list = subscriptions;
subscriptions = null;
}
unsubscribeFromAll(list);
}
}
/**
* Returns true if this composite is not unsubscribed and contains subscriptions.
* @return {@code true} if this composite is not unsubscribed and contains subscriptions.
*/
public boolean hasSubscriptions() {
if (!unsubscribed) {
synchronized (this) {
return !unsubscribed && subscriptions != null && !subscriptions.isEmpty();
}
}
return false;
}
}