}
    }

    protected final Map<Key, CacheRecord> cache = new ConcurrentHashMap<>();

    @Override
    public Key createKey(List<Artifact> extensionArtifacts) {
        return new CacheKey(extensionArtifacts);
    }

    @Override
    public CacheRecord get(Key key) {
        return cache.get(key);
    }

    @Override
    public CacheRecord put(

        } else {
            return new ArrayList<>();
        }
    }

    @Override
    public ProjectRealmCache.CacheRecord createProjectRealm(
            MavenProject project, Model model, ProjectBuildingRequest request) {
        return new ProjectRealmCache.CacheRecord(null, null);
    }

    @Override
    public void selectProjectRealm(MavenProject project) {}

        artifactRepositories = repositorySystem.getEffectiveRepositories(artifactRepositories);

        return artifactRepositories;
    }

    @Override
    public synchronized ProjectRealmCache.CacheRecord createProjectRealm(
            MavenProject project, Model model, ProjectBuildingRequest request)
            throws PluginResolutionException, PluginVersionResolutionException, PluginManagerException {

            pluginDescriptor.setArtifacts(new ArrayList<>(cacheRecord.getArtifacts()));
            for (ComponentDescriptor<?> componentDescriptor : pluginDescriptor.getComponents()) {
                componentDescriptor.setRealm(cacheRecord.getRealm());
            }

            pluginRealmCache.register(project, cacheKey, cacheRecord);
        }
    }

     * @return The record with the project realm and extension artifact filter, never {@code null}.
     * @throws PluginResolutionException If any build extension could not be resolved.
     */
    ProjectRealmCache.CacheRecord createProjectRealm(MavenProject project, Model model, ProjectBuildingRequest request)
            throws PluginResolutionException, PluginVersionResolutionException, PluginManagerException;

    /**

    /**
     * Sets up class realm for the specified build extensions plugin.
     *
     * @since 3.3.0
     */
    ExtensionRealmCache.CacheRecord setupExtensionsRealm(
            MavenProject project, Plugin plugin, RepositorySystemSession session) throws PluginManagerException;

    /**

        ProjectArtifactsCache.Key cacheKey = projectArtifactsCache.createKey(
                project, scopesToCollect, scopesToResolve, aggregating, session.getRepositorySession());

        ProjectArtifactsCache.CacheRecord recordArtifacts;
        recordArtifacts = projectArtifactsCache.get(cacheKey);
        if (recordArtifacts == null) {
            synchronized (cacheKey) {

        project.setPluginArtifactRepositories(pluginRepositories);

        if (request.getRequestType() == ModelBuilderRequest.RequestType.BUILD_PROJECT) {
            try {
                ProjectRealmCache.CacheRecord record =
                        projectBuildingHelper.createProjectRealm(project, model3, projectBuildingRequest);

                project.setClassRealm(record.getRealm());