import com.google.errorprone.annotations.concurrent.LazyInit;
import java.util.Collections;
import java.util.List;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/** Aggregate future that collects (stores) results of each future. */
@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
abstract class CollectionFuture<V extends @Nullable Object, C extends @Nullable Object>

import java.util.logging.Level;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A helper which does some thread-safe operations for aggregate futures, which must be implemented
 * differently in GWT. Namely:
 *
 * <ul>
 *   <li>Lazily initializes a set of seen exceptions
 *   <li>Decrements a counter atomically
 * </ul>
 */

import java.util.concurrent.Executor;
import java.util.concurrent.RejectedExecutionException;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/** Aggregate future that computes its value by calling a callable. */
@GwtCompatible
@ElementTypesAreNonnullByDefault
final class CombinedFuture<V extends @Nullable Object>
    extends AggregateFuture<@Nullable Object, V> {