}

    public void addNode(MetadataGraphNode node) {
        nodes.add(node);
    }

    /**
     * find a node by the GAV (metadata)
     *
     * @param md
     */
    public MetadataGraphNode findNode(MavenArtifactMetadata md) {
        for (MetadataGraphNode mgn : nodes) {
            if (mgn.metadata.equals(md)) {
                return mgn;
            }
        }

        return null;
    }

    @Override
    public List<String> findVersions(Artifact artifact) {
        return Collections.emptyList();
    }

    @Override
    public Model findModel(Artifact artifact) {
        if (GROUP_ID.equals(artifact.getGroupId())
                && ARTIFACT_ID.equals(artifact.getArtifactId())
                && VERSION.equals(artifact.getVersion())) {