com.hazelcast.com.google.common.util.concurrent.CollectionFuture Maven / Gradle / Ivy
/*
* Copyright (C) 2006 The Guava Authors
*
* 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 com.hazelcast.com.google.common.util.concurrent;
import static com.hazelcast.com.google.common.collect.Lists.newArrayListWithCapacity;
import static java.util.Collections.unmodifiableList;
import com.hazelcast.com.google.common.annotations.GwtCompatible;
import com.hazelcast.com.google.common.collect.ImmutableCollection;
import com.hazelcast.com.google.common.collect.ImmutableList;
import com.hazelcast.com.google.common.collect.Lists;
import java.util.List;
import com.hazelcast.org.checkerframework.checker.nullness.qual.Nullable;
/** Aggregate future that collects (stores) results of each future. */
@GwtCompatible(emulated = true)
abstract class CollectionFuture extends AggregateFuture {
/*
* We access this field racily but safely. For discussion of a similar situation, see the comments
* on the fields of TimeoutFuture. This field is slightly different than the fields discussed
* there: cancel() never reads this field, only writes to it. That makes the race here completely
* harmless, rather than just 99.99% harmless.
*/
private List> values;
CollectionFuture(
ImmutableCollection extends ListenableFuture extends V>> futures,
boolean allMustSucceed) {
super(futures, allMustSucceed, true);
List> values =
futures.isEmpty()
? ImmutableList.>of()
: Lists.>newArrayListWithCapacity(futures.size());
// Populate the results list with null initially.
for (int i = 0; i < futures.size(); ++i) {
values.add(null);
}
this.values = values;
}
@Override
final void collectOneValue(int index, @Nullable V returnValue) {
List> localValues = values;
if (localValues != null) {
localValues.set(index, new Present<>(returnValue));
}
}
@Override
final void handleAllCompleted() {
List> localValues = values;
if (localValues != null) {
set(combine(localValues));
}
}
@Override
void releaseResources(ReleaseResourcesReason reason) {
super.releaseResources(reason);
this.values = null;
}
abstract C combine(List> values);
/** Used for {@link Futures#allAsList} and {@link Futures#successfulAsList}. */
static final class ListFuture extends CollectionFuture> {
ListFuture(
ImmutableCollection extends ListenableFuture extends V>> futures,
boolean allMustSucceed) {
super(futures, allMustSucceed);
init();
}
@Override
public List combine(List> values) {
List result = newArrayListWithCapacity(values.size());
for (Present element : values) {
result.add(element != null ? element.value : null);
}
return unmodifiableList(result);
}
}
/** The result of a successful {@code Future}. */
private static final class Present {
V value;
Present(V value) {
this.value = value;
}
}
}
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