* build a smaller set of projects but perform other operations in the context of your reactor.
     */
    private List<MavenProject> allProjects;

    private MavenProject topLevelProject;

    private ProjectDependencyGraph projectDependencyGraph;

    private boolean parallel;

    /**
     * Plugin context keyed by project ({@link MavenProject#getId()}) and by plugin lookup key

 * that the plugins/mojos can be used in arbitrary contexts. In particular, the mojos can be used for ordinary build
 * plugins as well as special purpose plugins like reports.
 *
 * @since 3.0
 */
@Named
@Singleton
public class DefaultMavenPluginManager implements MavenPluginManager {

    /**
     * <p>
     * PluginId =&gt; ExtensionRealmCache.CacheRecord map MavenProject context value key. The map is used to ensure the

        assertFileExistence(dir, filename, true);

        File file = new File(dir, filename);

        String contents = FileUtils.fileRead(file, encoding);

        assertEquals(contentsTest, contents);
    }

    public File createFile(File dir, String filename, String contents, String encoding) throws IOException {
        File file = new File(dir, filename);

        file.getParentFile().mkdirs();

    }

    /**
     * Simply converts the given content to an xml string.
     *
     * @param content the object to convert
     * @return the xml string representation
     * @throws XmlWriterException if an error occurs during the transformation
     * @see #fromXmlString(String)
     */
    public static String toXml(@Nonnull Model content) throws XmlWriterException {

    }

    /**
     * Simply converts the given content to an xml string.
     *
     * @param content the object to convert
     * @return the xml string representation
     * @throws XmlWriterException if an error occurs during the transformation
     * @see #fromXmlString(String)
     */
    public static String toXml(@Nonnull Model content) throws XmlWriterException {

    /**
     * Sets the value of the context value of this project identified by the given key. If the supplied value is
     * <code>null</code>, the context value is removed from this project. Context values are intended to allow core
     * extensions to associate derived state with project instances.
     */
    public void setContextValue(String key, Object value) {
        if (context == null) {
            context = new HashMap<>();

     * The returned list of versions is only dependent on the configured repositories and their contents.
     * The supplied request may also refer to a single concrete version rather than a version range.
     * In this case though, the result contains simply the (parsed) input version, regardless of the
     * repositories and their contents.
     *
     * @param artifact the artifact for which to resolve the versions

        }

        boolean active = ensureAtLeastOneNonNull(os);

        String actualOsName = context.getSystemProperties().get("os.name").toLowerCase(Locale.ENGLISH);
        String actualOsArch = context.getSystemProperties().get("os.arch").toLowerCase(Locale.ENGLISH);
        String actualOsVersion = context.getSystemProperties().get("os.version").toLowerCase(Locale.ENGLISH);

        if (active && os.getFamily() != null) {

                    property.getLocation(""));
            return false;
        }

        String sysValue = context.getUserProperties().get(name);
        if (sysValue == null) {
            sysValue = context.getSystemProperties().get(name);
        }

        String propValue = property.getValue();
        if (propValue != null && !propValue.isEmpty()) {

        return !Boolean.parseBoolean(prop);
    }

    @Override
    public DependencyTraverser deriveChildTraverser(DependencyCollectionContext context) {
        requireNonNull(context, "context cannot be null");
        return this;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;