MaybePath

MaybePath<A> wraps Maybe<A> for computations that might produce nothing. It's the simplest failure mode: either you have a value, or you don't.

Creation

// From a value
MaybePath<String> greeting = Path.just("hello");

// Absence
MaybePath<String> nothing = Path.nothing();

// From existing Maybe
MaybePath<User> user = Path.maybe(repository.findById(id));

// From nullable (null becomes Nothing)
MaybePath<String> fromNullable = Path.fromNullable(possiblyNull);

Core Operations

MaybePath<String> name = Path.just("Alice");

// Transform
MaybePath<Integer> length = name.map(String::length);  // Just(5)

// Chain
MaybePath<String> upper = name.via(s -> Path.just(s.toUpperCase()));

// Combine independent values
MaybePath<Integer> age = Path.just(25);
MaybePath<String> summary = name.zipWith(age, (n, a) -> n + " is " + a);
// Just("Alice is 25")

Recovery

MaybePath<User> user = Path.maybe(findUser(id))
    .orElse(() -> Path.just(User.guest()));

// Filter (returns Nothing if predicate fails)
MaybePath<Integer> positive = Path.just(42).filter(n -> n > 0);  // Just(42)
MaybePath<Integer> rejected = Path.just(-1).filter(n -> n > 0);  // Nothing

Extraction

MaybePath<String> path = Path.just("hello");

Maybe<String> maybe = path.run();
String value = path.getOrElse("default");
String value = path.getOrThrow(() -> new NoSuchElementException());

When to Use

MaybePath is right when:

• Absence is normal, not exceptional
• You don't need to explain why the value is missing
• You're modelling optional data (configuration, nullable fields, lookups)

MaybePath is wrong when:

• Callers need to know the reason for failure → use EitherPath
• You're wrapping code that throws → use TryPath

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