mojos.put(Thread.currentThread(), mojoDescriptor);
            if (session.getRequest().getDegreeOfConcurrency() > 1) {
                boolean aggregator = mojoDescriptor.isAggregator();
                acquiredAggregatorLock = aggregator ? aggregatorLock.writeLock() : aggregatorLock.readLock();
                acquiredProjectLock = getProjectLock(session);
                if (!acquiredAggregatorLock.tryLock()) {

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>
 */

    }

    @Override
    public CacheStats stats() {
      SimpleStatsCounter aggregator = new SimpleStatsCounter();
      aggregator.incrementBy(localCache.globalStatsCounter);
      for (Segment<K, V> segment : localCache.segments) {
        aggregator.incrementBy(segment.statsCounter);
      }
      return aggregator.snapshot();
    }

    @Override
    public void cleanUp() {

            try {
                c.accept(pluginDescriptor);
            } catch (IllegalStateException e) {
                prerequisiteExceptions.add(e);
            }
        });
        // aggregate all exceptions
        if (!prerequisiteExceptions.isEmpty()) {
            String messages = prerequisiteExceptions.stream()
                    .map(IllegalStateException::getMessage)

        msgs.add("* An aggregator Mojo is already executing in parallel build,    *");
        msgs.add("* but aggregator Mojos require exclusive access to reactor to   *");
        msgs.add("* prevent race conditions. This mojo execution will be blocked  *");
        msgs.add("* until the aggregator work is done.                            *");

    @Nonnull
    RemoteRepository createRemote(@Nonnull String id, @Nonnull String url);

    @Nonnull
    RemoteRepository createRemote(@Nonnull Repository repository);

    @Nonnull
    List<RemoteRepository> aggregate(
            @Nonnull Session session,
            @Nonnull List<RemoteRepository> dominant,
            @Nonnull List<RemoteRepository> recessive,
            boolean processRecessive);

          + aggregateAboveRange(aggr, node.left);
    }
  }

  @Override
  public int size() {
    return Ints.saturatedCast(aggregateForEntries(Aggregate.SIZE));
  }

  @Override
  int distinctElements() {
    return Ints.saturatedCast(aggregateForEntries(Aggregate.DISTINCT));
  }

  static int distinctElements(@CheckForNull AvlNode<?> node) {
    return (node == null) ? 0 : node.distinctElements;
  }

    }

    @Override
    public CacheStats stats() {
      SimpleStatsCounter aggregator = new SimpleStatsCounter();
      aggregator.incrementBy(localCache.globalStatsCounter);
      for (Segment<K, V> segment : localCache.segments) {
        aggregator.incrementBy(segment.statsCounter);
      }
      return aggregator.snapshot();
    }

    @Override
    public void cleanUp() {

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>

                scenario("Selected aggregator project (including child modules)")
                        .activeRequiredProjects(MODULE_C)
                        .expectResult(MODULE_C, MODULE_C_1, MODULE_C_2),
                scenario("Selected aggregator project with non-recursive")
                        .activeRequiredProjects(MODULE_C)