// +optional
  optional UserSubject user = 2;

  // `group` matches based on user group name.
  // +optional
  optional GroupSubject group = 3;

  // `serviceAccount` matches ServiceAccounts.
  // +optional
  optional ServiceAccountSubject serviceAccount = 4;
}

// UserSubject holds detailed information for user-kind subject.
message UserSubject {

  }

  @AndroidIncompatible
  public void testJavaOptional() {
    FreshValueGenerator generator = new FreshValueGenerator();
    assertEquals(Optional.empty(), generator.generateFresh(new TypeToken<Optional<String>>() {}));
    assertEquals(Optional.of("2"), generator.generateFresh(new TypeToken<Optional<String>>() {}));

  source:
    type: minio # valid values are "s3" or "minio"
    bucket: mytest
    prefix: object-prefix1 # 'PREFIX' is optional
    # If your source is the 'local' alias specified to 'mc batch start', then the 'endpoint' and 'credentials' fields are optional and can be omitted
    # Either the 'source' or 'remote' *must* be the "local" deployment
#    endpoint: "http://127.0.0.1:9000"

        }
        return root;
      }
    },
    ALL_RIGHT {
      @Override
      Optional<BinaryNode> createTree(int size, Random rng) {
        Optional<BinaryNode> root = Optional.absent();
        for (int i = 0; i < size; i++) {
          root = Optional.of(new BinaryNode(rng.nextInt(), Optional.<BinaryNode>absent(), root));
        }
        return root;
      }
    },
    RANDOM {

        return returnFirstPresentOrEmpty(MavenOptions::resumeFrom);
    }

    @Override
    public Optional<List<String>> projects() {
        return collectListIfPresentOrEmpty(MavenOptions::projects);
    }

    @Override
    public Optional<Boolean> alsoMake() {
        return returnFirstPresentOrEmpty(MavenOptions::alsoMake);
    }

    @Override

    private ProtoLookup(Map<Class<?>, Object> components) {
        this.components = components;
    }

    @Override
    public <T> T lookup(Class<T> type) {
        Optional<T> optional = lookupOptional(type);
        if (optional.isPresent()) {
            return optional.get();
        } else {
            throw new LookupException("No mapping for key: " + type.getName());
        }
    }

    @Override

     * @param active Should the profile be activated?
     * @param optional Can the build continue if the profile does not exist?
     */
    public void addProfileActivation(String id, boolean active, boolean optional) {
        final ActivationSettings settings = ActivationSettings.of(active, optional);
        this.activations.put(id, settings);
    }

  // in the zone and nodeName fields instead.
  // +optional
  map<string, string> deprecatedTopology = 5;

  // nodeName represents the name of the Node hosting this endpoint. This can
  // be used to determine endpoints local to a Node.
  // +optional
  optional string nodeName = 6;

  // zone is the name of the Zone this endpoint exists in.
  // +optional
  optional string zone = 7;

    /**
     * Performs a lookup for optional typed component.
     *
     * @param type The component type.
     * @return Optional carrying component or empty optional if no such component.
     * @param <T> The component type.
     * @throws LookupException if there is some provisioning related issue.
     */
    @Nonnull
    <T> Optional<T> lookupOptional(Class<T> type);

    /**

  // +optional
  optional string status = 6;

  // brief reason for the request state
  // +optional
  optional string reason = 2;

  // human readable message with details about the request state
  // +optional
  optional string message = 3;

  // timestamp for the last update to this condition
  // +optional
  optional k8s.io.apimachinery.pkg.apis.meta.v1.Time lastUpdateTime = 4;