* Create a key using the given class as an identifier and as the type of the object.
     */
    static <T> Key<T> key(Class<T> clazz) {
        return new Key<>(clazz, clazz);
    }

    /**
     * Create a key using the given class and id.
     */
    static <T> Key<T> key(Class<T> clazz, Object id) {
        return new Key<>(clazz, id);
    }

    /**
     * Key used to query the session data

                    //noinspection unchecked
                    return () -> (Q) list(list);
                }
                if (key.getRawType() == Map.class) {
                    Key<?> k = key.getTypeParameter(0);
                    Key<Object> v = key.getTypeParameter(1);
                    if (k.getRawType() == String.class) {
                        Set<Binding<Object>> res2 = getBindings(v);

            this.realm = realm;
            this.extensionArtifactFilter = extensionArtifactFilter;
        }
    }

    Key createKey(List<? extends ClassRealm> extensionRealms);

    CacheRecord get(Key key);

    CacheRecord put(Key key, ClassRealm projectRealm, DependencyFilter extensionArtifactFilter);

    void flush();

    /**

            Collection<String> artifacts,
            Collection<String> packages,
            String key,
            XmlNode configuration) {
        this.realm = realm;
        this.artifacts = Collections.unmodifiableSet(new HashSet<>(artifacts));
        this.packages = Collections.unmodifiableSet(new HashSet<>(packages));
        this.key = key;
        this.configuration = configuration;
    }

    /**

    }

    @Override
    public boolean equals(Object o) {
        return o instanceof Artifact && Objects.equals(key(), ((Artifact) o).key());
    }

    @Override
    public int hashCode() {
        return key.hashCode();
    }

    @Override
    public String toString() {
        return artifact.toString();
    }

    private static final String ISSUES_KEY = DefaultPluginValidationManager.class.getName() + ".issues";

    private static final String PLUGIN_EXCLUDES_KEY = DefaultPluginValidationManager.class.getName() + ".excludes";

    private static final String MAVEN_PLUGIN_VALIDATION_KEY = "maven.plugin.validation";

    private static final String MAVEN_PLUGIN_VALIDATION_EXCLUDES_KEY = "maven.plugin.validation.excludes";

     * same class realm is used to load build extensions and load mojos for extensions=true plugins.
     * </p>
     * <strong>Note:</strong> This is part of internal implementation and may be changed or removed without notice
     *
     * @since 3.3.0
     */

            for (Plugin plugin : plugins) {
                Object key = plugin.getKey();
                Plugin first = normalized.get(key);
                if (first != null) {
                    plugin = merger.mergePlugin(plugin, first);
                }
                normalized.put(key, plugin);
            }

            if (plugins.size() != normalized.size()) {

        }
    }

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

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

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

    public CacheRecord put(Key key, ClassRealm projectRealm, DependencyFilter extensionArtifactFilter) {

    }

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

    @Override
    public CacheRecord get(Key key, PluginRealmSupplier supplier)
            throws PluginResolutionException, PluginContainerException {
        try {
            return cache.computeIfAbsent(key, k -> {
                try {
                    return supplier.load();