* Gets the exceptions that occurred while resolving the version range.
     *
     * @return The list of exceptions that occurred during resolution, never {@code null}
     */
    @Nonnull
    List<Exception> getExceptions();

    /**
     * Gets the versions (in ascending order) that matched the requested range.
     *
     * @return The list of matching versions, never {@code null}. An empty list indicates

          });
      executor.execute(
          new Runnable() {
            @Override
            public void run() {
              future.setException(new IllegalArgumentException("failure"));
              if (!future.isDone()) {
                errorMessage.set("SetException call exited before future was complete.");
              }
            }
          });
      executor.execute(
          new Runnable() {

      // As soon as the first one fails, make that failure the result of the output future.
      // The results of all other inputs are then ignored (except for logging any failures).
      boolean completedWithFailure = setException(throwable);
      if (!completedWithFailure) {
        // Go up the causal chain to see if we've already seen this cause; if we have, even if
        // it's wrapped by a different exception, don't log it.

  }

  static final class ImmediateFailedFuture<V extends @Nullable Object> extends TrustedFuture<V> {
    ImmediateFailedFuture(Throwable thrown) {
      setException(thrown);
    }
  }

  static final class ImmediateCancelledFuture<V extends @Nullable Object> extends TrustedFuture<V> {
    static final @Nullable ImmediateCancelledFuture<Object> INSTANCE =

    SettableFuture<String> f = SettableFuture.create();
    Exception e = new IllegalArgumentException("foo not found");
    MockCallback callback = new MockCallback(e);
    addCallback(f, callback, directExecutor());
    f.setException(e);
  }

  public void testCancel() {
    SettableFuture<String> f = SettableFuture.create();
    FutureCallback<String> callback =
        new FutureCallback<String>() {

      case NOT_DONE:
        break;
      case FINISHED:
        f.set(null);
        break;
      case CANCELLED:
        f.cancel(false);
        break;
      case FAILED:
        f.setException(new Exception());
        break;
    }
    return f;
  }

    /**
     * Gets the exceptions that occurred while building the dependency graph.
     *
     * @return the exceptions that occurred, never {@code null}
     */
    @Nonnull
    List<Exception> getExceptions();

    /**
     * Gets the root node of the dependency graph.
     *
     * @return the root node of the dependency graph or {@code null} if none
     */
    @Nullable
    Node getRoot();

    /**

    SettableFuture<String> f = SettableFuture.create();
    Exception e = new IllegalArgumentException("foo not found");
    MockCallback callback = new MockCallback(e);
    addCallback(f, callback, directExecutor());
    f.setException(e);
  }

  public void testCancel() {
    SettableFuture<String> f = SettableFuture.create();
    FutureCallback<String> callback =
        new FutureCallback<String>() {

                System.err.println("Missing: " + artifact);
            }
        }

        if (result.hasExceptions()) {
            for (Exception e : result.getExceptions()) {
                e.printStackTrace();
            }
        }
    }

    // ------------------------------------------------------------------------

    public boolean hasExceptions() {
        return exceptions != null && !exceptions.isEmpty();
    }

    public List<Exception> getExceptions() {
        return exceptions == null ? Collections.emptyList() : Collections.unmodifiableList(exceptions);
    }

    // ------------------------------------------------------------------------