}

        CacheRecord(LifecycleExecutionException exception) {
            this.artifacts = null;
            this.exception = exception;
        }

        public Set<Artifact> getArtifacts() {
            return artifacts;
        }

        public LifecycleExecutionException getException() {
            return exception;
        }
    }

    Key createKey(

        public ClassRealm getRealm() {
            return realm;
        }

        public ExtensionDescriptor getDescriptor() {
            return descriptor;
        }

        public List<Artifact> getArtifacts() {
            return artifacts;
        }
    }

    Key createKey(List<Artifact> extensionArtifacts);

    CacheRecord get(Key key);

    CacheRecord put(

        assertEquals(pom0Basedir, project1.getParent().getBasedir());
        System.out.println("Project " + project1.getId() + " " + project1);
        Set set = project1.getArtifacts();
        assertNotNull(set, "No artifacts");
        assertFalse(set.isEmpty(), "No Artifacts");
        assertTrue(set.size() == 3, "Set size should be 3, is " + set.size());

        for (Object aSet : set) {

        // marker interface for cache keys
    }

    /**
     * CacheRecord
     */
    class CacheRecord {

        private final List<Artifact> artifacts;

        public List<Artifact> getArtifacts() {
            return artifacts;
        }

        public PluginResolutionException getException() {
            return exception;
        }

        private final PluginResolutionException exception;

    }

    @Override
    public Artifact getArtifact() {
        return artifact;
    }

    @Override
    public DefaultMetadataResolutionRequest setArtifact(Artifact artifact) {
        this.artifact = artifact;

        return this;
    }

    @Override
    public ArtifactRepository getLocalRepository() {
        return repositoryRequest.getLocalRepository();

        field.set(reader, eventDispatcher);

        ArtifactDescriptorRequest request = new ArtifactDescriptorRequest();

        request.addRepository(newTestRepository());

        request.setArtifact(new DefaultArtifact("org.apache.maven.its", "dep-mng5459", "jar", "0.4.0-SNAPSHOT"));

        // execute
        reader.readArtifactDescriptor(session, request);

        // verify

            throws ArtifactMetadataRetrievalException {
        MetadataResolutionRequest request = new DefaultMetadataResolutionRequest();
        injectSession(request);
        request.setArtifact(artifact);
        request.setLocalRepository(localRepository);
        request.setRemoteRepositories(remoteRepositories);
        request.setResolveManagedVersions(resolveManagedVersions);
        return retrieve(request);

     * Sets the artifact for which to resolve metadata.
     *
     * @param artifact The artifact for which to resolve metadata.
     * @return This request, never {@code null}.
     */
    MetadataResolutionRequest setArtifact(Artifact artifact);

    /**
     * Gets the local repository to use for the resolution.
     *
     * @return The local repository to use for the resolution or {@code null} if not set.
     */
    @Override

    }

    @Nonnull
    @Override
    public String getVersion() {
        return project.getVersion();
    }

    @Nonnull
    @Override
    public List<ProducedArtifact> getArtifacts() {
        org.eclipse.aether.artifact.Artifact pomArtifact = RepositoryUtils.toArtifact(new ProjectArtifact(project));
        org.eclipse.aether.artifact.Artifact projectArtifact = RepositoryUtils.toArtifact(project.getArtifact());

                relatedMetadata.put(snapshotKey, (MergeableMetadata) metadata);
            }
        }

        artifact.setResolvedVersion(result.getArtifacts().iterator().next().getVersion());
    }