Optional() {}

  /**
   * Returns {@code true} if this holder contains a (non-null) instance.
   *
   * <p><b>Comparison to {@code java.util.Optional}:</b> no differences.
   */
  public abstract boolean isPresent();

  /**
   * Returns the contained instance, which must be present. If the instance might be absent, use
   * {@link #or(Object)} or {@link #orNull} instead.
   *

        context.indent();

        if (options.all().orElse(false)) {
            context.info("all: true (applying all available upgrades)");
        }

        if (options.modelVersion().isPresent()) {
            context.info("modelVersion: " + options.modelVersion().get());
        }

        if (options.plugins().orElse(false)) {
            context.info("plugins: true");
        }

        if (planStep.isPresent() && planStep.get().status.get() == BuildStep.PLANNING) {
            writer.accept("Build plan will be lazily computed");
        } else {
            plan.steps(project)
                    .filter(step ->
                            step.phase != null && step.executions().findAny().isPresent())

    void testKnownMapping() {
        final int dosErr = 0x00010001;
        final int expectedNt = 0xc0000002;
        Optional<Integer> actual = findNtStatus(dosErr);
        assertTrue(actual.isPresent(), String.format("Mapping for %08x should exist", dosErr));
        assertEquals(expectedNt, actual.get(), String.format("NTSTATUS for %08x should be %08x", dosErr, expectedNt));
    }

    @Test

        if (context.options().help().isPresent()) {
            Consumer<String> writer = determineWriter(context);
            context.options().displayHelp(context.invokerRequest.parserRequest(), writer);
            throw new InvokerException.ExitException(0);
        }
        if (context.options().showVersionAndExit().isPresent()) {
            showVersion(context);

            String fieldKey = field.getKey();
            String fieldDescription = "Configure " + fieldKey + ": " + field.getDescription();
            if (field.getOptions().isPresent()) {
                // list options
                ListPromptBuilder listPromptBuilder =
                        promptBuilder.createListPrompt().name(fieldKey).message(fieldDescription);

        ArrayList<CIInfo> result = ServiceLoader.load(CIDetector.class).stream()
                .map(ServiceLoader.Provider::get)
                .map(CIDetector::detectCI)
                .filter(Optional::isPresent)
                .map(Optional::get)
                .collect(Collectors.toCollection(ArrayList::new));

        if (result.size() > 1) {
            // remove generic

        // CLI args
        MavenOptions cliOptions = parseMavenCliOptions(context.parserRequest.args());
        result.add(cliOptions);
        // atFile option
        if (cliOptions.atFile().isPresent()) {
            Path file = context.cwd.resolve(cliOptions.atFile().orElseThrow());
            if (Files.isRegularFile(file)) {
                result.add(parseMavenAtFileOptions(file));
            } else {

  }

  public void testIsPresent_no() {
    assertFalse(Optional.absent().isPresent());
  }

  @SuppressWarnings("OptionalOfRedundantMethod") // Unit tests for Optional
  public void testIsPresent_yes() {
    assertTrue(Optional.of("training").isPresent());
  }

  public void testGet_absent() {
    Optional<String> optional = Optional.absent();

  @SuppressWarnings("unchecked") // implementation is "fully variant"
  static <T> Optional<T> withType() {
    return (Optional<T>) INSTANCE;
  }

  private Absent() {}

  @Override
  public boolean isPresent() {
    return false;
  }

  @Override
  public T get() {
    throw new IllegalStateException("Optional.get() cannot be called on an absent value");
  }

  @Override
  public T or(T defaultValue) {