Match(10).option(
Case(x -> x > 10, x -> x + " is larger than 10"),
Case(x -> x < 10, x -> x + " is smaller than 10"),
Case($(10), x -> x + " is 10"),
Default(x -> x + " is stranger than we thought")
);
- The first parameter of
Case gets a predicate to match the match value with.
- The second parameter of
Case has two options: a literal value, or a mapper for the match value.
Default case works like Scalas case _.$ sign is a utility function that creates a predicate which matches the match value to a given literal.
Match(LocalDate.now()).of(
Case(date -> date.isAfter(LocalDate.now()), "its later then now"),
Case(date -> date.isBefore(LocalDate.now()), "its before now"),
Case(instanceOf(Date.class), "its a local date"),
Case($(LocalDate.now()), "its today"),
Default("somethings wrong")
Default("somethings wrong 2")
);
instanceOf is a built-in utility function that creates a predicate.- When two
Default cases will be written, a warning will be printed to stdout.
Match(Optional.of(5)).of(
Case($d($(4)), "it holds 4"),
Case($d($(5)), "it holds 5"),
Default(x -> x + "some optional")
);
$d is a "destructure" method that allows to "map" over classes which have wrappers with a get method, like
Optional. It receives a Predicate<(innerValue)>, extracts the inner value and applies the predicate on it.