}

    public void renderTo(ClassExtensionDoc extension, Element parent) {
        if (extension.getExtensionBlocks().isEmpty()) {
            return;
        }

        Document document = parent.getOwnerDocument();

        Element section = document.createElement("section");
        parent.appendChild(section);

        Element title = document.createElement("title");

<project>
  <parent>
    <artifactId>p0</artifactId>
    <groupId>maven</groupId>
    <version>1.0</version>
  </parent>
  <modelVersion>4.0.0</modelVersion>
  <groupId>maven</groupId>
  <artifactId>p1</artifactId>
  <packaging>pom</packaging>
  <name>p1</name>
  <version>1.0</version>
  <scm>
    <url>scm-url</url>
  </scm>

<project>
  <parent>
    <artifactId>p2</artifactId>
    <groupId>maven.t01</groupId>
    <version>1.0</version>
  </parent>
  <modelVersion>4.0.0</modelVersion>
  <groupId>maven.t01</groupId>
  <artifactId>p3</artifactId>
  <packaging>pom</packaging>
  <name>p3</name>
  <version>1.0</version>
  <organization>
    <name>p3-org</name>
  </organization>

    }

    public void setMd(ArtifactMetadata md) {
        this.md = md;
    }

    public MetadataTreeNode getParent() {
        return parent;
    }

    public void setParent(MetadataTreeNode parent) {
        this.parent = parent;
    }

    public MetadataTreeNode[] getChildren() {
        return children;
    }

    public void setChildren(MetadataTreeNode[] children) {

    Document document
    Node parent
    List elements = []

    def DomBuilder(Document document) {
        this.document = document
        this.parent = document
    }

    def DomBuilder(Node parent) {
        this.document = parent.ownerDocument
        this.parent = parent
    }

    def DomBuilder(Document document, Node parent) {
        this.document = document

                        <version>1.0.0</version>
                    </parent>
                    <artifactId>child-project</artifactId>
                    <!-- groupId and version inherited from parent -->
                </project>
                """;

            Document document = Document.of(pomXml);
            UpgradeContext context = createMockContext();

    File parent = file.getParentFile();
    File grandparent = parent.getParentFile();
    assertFalse(grandparent.exists());
    Files.createParentDirs(file);
    assertTrue(parent.exists());
  }

  public void testCreateParentDirs_nonDirectoryParentExists() throws IOException {
    File parent = getTestFile("ascii.txt");
    assertTrue(parent.isFile());

<project>
  <modelVersion>4.0.0</modelVersion>

  <parent>
    <groupId>lifecycle-participant-reactor-dependency-injection</groupId>
    <artifactId>parent</artifactId>
    <version>1.0</version>
  </parent>

  <artifactId>module-b</artifactId>

    }

    public void mergeContent(ClassDoc classDoc, Element parent) {
        listener.start(String.format("class %s", classDoc.getName()));
        try {
            Element chapter = parent.getOwnerDocument().createElement("chapter");
            parent.appendChild(chapter);
            chapter.setAttribute("id", classDoc.getId());

    /**
     * Merges values from the specified parent model into the given child model. Implementations are expected to keep
     * parent and child completely decoupled by injecting deep copies of objects into the child rather than the original
     * objects from the parent.
     *
     * @param child The child model into which to merge the values inherited from the parent, must not be
     *            <code>null</code>.