}
      // re-read valueField, if we get here then we must have observed a TOMBSTONE while trying to
      // add a waiter.
      // requireNonNull is safe because valueField is always set before TOMBSTONE.
      return getDoneValue(requireNonNull(valueField));
    }
    // If we get here then we have remainingNanos < SPIN_THRESHOLD_NANOS and there is no node on the
    // waiters list

        } else {
            this.proxies = null;
        }

        return this;
    }

    @Override
    public MavenExecutionRequest addProxy(Proxy proxy) {
        Objects.requireNonNull(proxy, "proxy cannot be null");

        for (Proxy p : getProxies()) {
            if (p.getId() != null && p.getId().equals(proxy.getId())) {
                return this;
            }
        }

import static java.util.Objects.requireNonNull;

/**
 * A class building reverse tree using {@link CollectStepData} trace data provided in {@link RepositoryEvent}
 * events fired during collection.
 *
 * @since 3.9.0
 */
class ReverseTreeRepositoryListener extends AbstractRepositoryListener {
    @Override
    public void artifactResolved(RepositoryEvent event) {
        requireNonNull(event, "event cannot be null");

      public @Nullable V remove(@Nullable Object key) {
        V value = get(key);
        if (value != null) {
          // it's definitely in the map, so the cast and requireNonNull are safe
          @SuppressWarnings("unchecked")
          Range<K> range = (Range<K>) requireNonNull(key);
          TreeRangeMap.this.remove(range);
          return value;
        }
        return null;
      }

      @Override

      checkState(
          state == FAILED,
          "failureCause() is only valid if the service has failed, service is %s",
          state);
      // requireNonNull is safe because the constructor requires a non-null cause with state=FAILED.
      return requireNonNull(failure);
    }
  }

    public CacheRecord get(Key key) {
        return cache.get(key);
    }

    @Override
    public CacheRecord put(Key key, ClassRealm projectRealm, DependencyFilter extensionArtifactFilter) {
        Objects.requireNonNull(projectRealm, "projectRealm cannot be null");

        if (cache.containsKey(key)) {
            throw new IllegalStateException("Duplicate project realm for extensions " + key);
        }

     * @param wallTime The wall time of the project in milliseconds.
     */
    protected BuildSummary(MavenProject project, Duration execTime, Duration wallTime) {
        this.project = Objects.requireNonNull(project, "project cannot be null");
        // TODO Validate for < 0?
        this.execTime = execTime;
        this.wallTime = wallTime;
    }

    /**
     * Gets the project being summarized.
     *

      }
      laterCount--;
      canRemove = true;
      /*
       * requireNonNull is safe because laterCount starts at 0, forcing us to initialize
       * currentEntry above. After that, we never clear it.
       */
      return requireNonNull(currentEntry).getElement();
    }

    @Override
    public void remove() {
      checkRemove(canRemove);

      }
      laterCount--;
      canRemove = true;
      /*
       * requireNonNull is safe because laterCount starts at 0, forcing us to initialize
       * currentEntry above. After that, we never clear it.
       */
      return requireNonNull(currentEntry).getElement();
    }

    @Override
    public void remove() {
      checkRemove(canRemove);

   */

  private Object requireTable() {
    return requireNonNull(table);
  }

  private int[] requireEntries() {
    return requireNonNull(entries);
  }

  private @Nullable Object[] requireKeys() {
    return requireNonNull(keys);
  }

  private @Nullable Object[] requireValues() {
    return requireNonNull(values);
  }

  /*