}
        }
    }

    public List<MavenProject> getUpstreamProjects(MavenProject project, boolean transitive) {
        Objects.requireNonNull(project, "project cannot be null");

        Set<String> projectIds = new HashSet<>();

        getUpstreamProjects(ProjectSorter.getId(project), projectIds, transitive);

        return getSortedProjects(projectIds);
    }

        return applyFilter(projectDependencyGraph.getDownstreamProjects(project, transitive), transitive, false);
    }

    @Override
    public List<MavenProject> getUpstreamProjects(MavenProject project, boolean transitive) {
        return applyFilter(projectDependencyGraph.getUpstreamProjects(project, transitive), transitive, true);
    }

    /**
     * Filter out whitelisted projects with a big twist:

     *            upstream projects.
     * @return The upstream projects in the build order, never {@code null}.
     */
    List<MavenProject> getUpstreamProjects(MavenProject project, boolean transitive);