interface PluginDescriptorSupplier {
        PluginDescriptor load()
                throws PluginResolutionException, PluginDescriptorParsingException, InvalidPluginDescriptorException;
    }

    Key createKey(Plugin plugin, List<RemoteRepository> repositories, RepositorySystemSession session);

    void put(Key key, PluginDescriptor pluginDescriptor);

    PluginDescriptor get(Key key);

        // marker interface for cache keys
    }

    @FunctionalInterface
    interface PluginRealmSupplier {
        CacheRecord load() throws PluginResolutionException, PluginContainerException;
    }

    Key createKey(
            Plugin plugin,
            ClassLoader parentRealm,
            Map<String, ClassLoader> foreignImports,
            DependencyFilter dependencyFilter,
            List<RemoteRepository> repositories,

        public String toString() {
            return extensionRealms.toString();
        }
    }

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

    @Override
    public Key createKey(List<? extends ClassRealm> extensionRealms) {
        return new CacheKey(extensionRealms);
    }

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

    @Override

        public String toString() {
            return files.toString();
        }
    }

    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

    private Map<Key, Key> keys = new ConcurrentHashMap<>();

    @Override
    public void flush() {
        descriptors.clear();
    }

    @Override
    public Key createKey(Plugin plugin, List<RemoteRepository> repositories, RepositorySystemSession session) {
        return keys.computeIfAbsent(new CacheKey(plugin, repositories, session), k -> k);
    }

    @Override

            } else {
                return false;
            }
        }
    }

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

    @Override
    public Key createKey(
            Plugin plugin,
            DependencyFilter extensionFilter,
            List<RemoteRepository> repositories,
            RepositorySystemSession session) {

            throws PluginResolutionException, PluginDescriptorParsingException, InvalidPluginDescriptorException {
        PluginDescriptorCache.Key cacheKey = pluginDescriptorCache.createKey(plugin, repositories, session);

        PluginDescriptor pluginDescriptor = pluginDescriptorCache.get(cacheKey, () -> {
            org.eclipse.aether.artifact.Artifact artifact =

        if (logger.isDebugEnabled()) {
            logger.debug("Extension realms for project " + model.getId() + ": " + extensionRealms);
        }

        ProjectRealmCache.Key projectRealmKey = projectRealmCache.createKey(extensionRealms);

        ProjectRealmCache.CacheRecord record = projectRealmCache.get(projectRealmKey);

        if (record == null) {

    protected final Cache<Key, Key> keys = Cache.newCache(Cache.ReferenceType.SOFT, "ProjectArtifactsCache-Keys");

    @Override
    public Key createKey(
            MavenProject project,
            Collection<String> scopesToCollect,
            Collection<String> scopesToResolve,
            boolean aggregating,
            RepositorySystemSession session) {

            } else {
                return false;
            }
        }
    }

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

    @Override
    public Key createKey(
            Plugin plugin,
            ClassLoader parentRealm,
            Map<String, ClassLoader> foreignImports,
            DependencyFilter dependencyFilter,
            List<RemoteRepository> repositories,