return new Present<>(
        checkNotNull(
            function.apply(reference),
            "the Function passed to Optional.transform() must not return null."));
  }

  @Override
  public boolean equals(@CheckForNull Object object) {
    if (object instanceof Present) {
      Present<?> other = (Present<?>) object;
      return reference.equals(other.reference);
    }

    return new Present<>(
        checkNotNull(
            function.apply(reference),
            "the Function passed to Optional.transform() must not return null."));
  }

  @Override
  public boolean equals(@CheckForNull Object object) {
    if (object instanceof Present) {
      Present<?> other = (Present<?>) object;
      return reference.equals(other.reference);
    }

apiVersion: release-notes/v2
kind: bug-fix
area: traffic-management
issue:
  - 47341
releaseNotes:
- |

	}
	if !present {
		t.Errorf("Expected present")
	}

	v = ev.Get()
	if v != 123 {
		t.Errorf("Expected 123, got %v", v)
	}

	_ = os.Setenv(testVar, "789")

	ev = RegisterIntVar(testVar, 123, "")
	v, present = ev.Lookup()
	if v != 789 {
		t.Errorf("Expected 789, got %v", v)
	}
	if !present {
		t.Errorf("Expected present")
	}

	v = ev.Get()
	if v != 789 {

// for execution or not.
type Selector struct {
	// The constraints are and'ed together.
	present Set
	absent  Set
}

var _ fmt.Stringer = Selector{}

// NewSelector returns a new selector based on the given presence/absence predicates.
func NewSelector(present []Instance, absent []Instance) Selector {
	return Selector{
		present: NewSet(present...),
		absent:  NewSet(absent...),
	}
}

  @CheckForNull @LazyInit private List<@Nullable Present<V>> values;

  CollectionFuture(
      ImmutableCollection<? extends ListenableFuture<? extends V>> futures,
      boolean allMustSucceed) {
    super(futures, allMustSucceed, true);

    List<@Nullable Present<V>> values =
        futures.isEmpty()
            ? Collections.<@Nullable Present<V>>emptyList()
            : Lists.<@Nullable Present<V>>newArrayListWithCapacity(futures.size());

        def provider = layout.projectDirectory.dir(pathProvider)
        !provider.present
        provider.getOrNull() == null
    }

    def "regular file is not present when path provider is not present"() {
        def pathProvider = withNoValue()

        expect:
        def provider = layout.projectDirectory.file(pathProvider)
        !provider.present
        provider.getOrNull() == null
    }

        instant.invalidated < instant.snapshottingFinished
        !vfs.findSnapshot(location).present
        !vfs.findSnapshot("${location}/some/child").present
        !vfs.findSnapshot("${location}/some/child2").present
        vfs.findSnapshot("${location}/other/child").present
        vfs.findSnapshot("${location}/other/child2").present
    }

    def "does not store snapshot when invalidate all happened in between"() {

    }

    def "can get by name before element is present and query after realized"() {
        def binary1 = Stub(SwiftBinary)
        binary1.name >> "test1"

        expect:
        def p = container.getByName("test1")
        !p.present

        container.add(binary1)

        !p.present

        container.realizeNow()

        p.present
        p.get() == binary1
    }

  @CheckForNull @LazyInit private List<@Nullable Present<V>> values;

  CollectionFuture(
      ImmutableCollection<? extends ListenableFuture<? extends V>> futures,
      boolean allMustSucceed) {
    super(futures, allMustSucceed, true);

    List<@Nullable Present<V>> values =
        futures.isEmpty()
            ? Collections.<@Nullable Present<V>>emptyList()
            : Lists.<@Nullable Present<V>>newArrayListWithCapacity(futures.size());