/**
     * construct a single vertex
     */
    public MetadataGraph(MetadataGraphVertex entry) throws MetadataResolutionException {
        checkVertex(entry);
        checkVertices(1);

        entry.setCompareVersion(versionedVertices);
        entry.setCompareScope(scopedVertices);

        vertices.add(entry);
        this.entry = entry;
    }
    // ------------------------------------------------------------------------