return "empty";
        }
        StringBuilder sb = new StringBuilder(512);
        for (MetadataGraphVertex v : vertices) {
            sb.append("Vertex:  ").append(v.getMd().toString()).append('\n');
            List<MetadataGraphEdge> ins = getIncidentEdges(v);
            if (ins != null) {
                for (MetadataGraphEdge e : ins) {
                    sb.append("       from :  ").append(e.toString()).append('\n');

    }

    public String toString() {
        StringBuilder sb = new StringBuilder(256);

        sb.append("      id: ").append(getId()).append(LS);
        sb.append("      url: ").append(getUrl()).append(LS);
        sb.append("   layout: ").append(layout != null ? layout : "none");

        if (proxy != null) {
            sb.append(LS)
                    .append("    proxy: ")

        StringBuilder sb = new StringBuilder();

        if (artifacts != null) {
            int i = 1;
            sb.append("---------").append(LS);
            sb.append(artifacts.size()).append(LS);
            for (Artifact a : artifacts) {
                sb.append(i).append(' ').append(a).append(LS);
                i++;
            }
            sb.append("---------");
        }

        }
    }

    File getTouchfile(Artifact artifact) {
        StringBuilder sb = new StringBuilder(128);
        sb.append(artifact.getArtifactId());
        sb.append('-').append(artifact.getBaseVersion());
        if (artifact.getClassifier() != null) {
            sb.append('-').append(artifact.getClassifier());
        }
        sb.append('.').append(artifact.getType()).append(LAST_UPDATE_TAG);

                sb.append("Try downloading the file manually from the project website.");
            }

            sb.append(LS);
            sb.append(LS);
            sb.append(indentation);
            sb.append("Then, install it using the command: ");
            sb.append(LS);
            sb.append(indentation);
            sb.append("    mvn install:install-file -DgroupId=");

        StringBuilder sb = new StringBuilder(128);
        sb.append(getGroupId());
        sb.append(':');
        appendArtifactTypeClassifierString(sb);
        return sb.toString();
    }

    private void appendArtifactTypeClassifierString(StringBuilder sb) {
        sb.append(getArtifactId());
        sb.append(':');
        sb.append(getType());
        if (hasClassifier()) {

        StringBuilder sb = new StringBuilder(128);
        sb.append("Mirror[");
        sb.append("id=").append(this.getId());
        sb.append(",mirrorOf=").append(this.getMirrorOf());
        sb.append(",url=").append(this.getUrl());
        sb.append(",name=").append(this.getName());
        if (isBlocked()) {
            sb.append(",blocked");
        }
        sb.append("]");
        return sb.toString();

        assertEquals(toString(expectedList), toString(actualList));
    }

    private static String toString(List<String> lines) {
        StringBuilder sb = new StringBuilder();
        for (String line : lines) {
            sb.append(line).append('\n');
        }
        return sb.toString();
    }