Offers domain-specific, immutable value types with enhanced type safety, preventing invalid states and reducing bugs. Includes domain-specific checks, helper functions, and transformations for clearer domain modeling.
This project is in an early stage of development, where structural and backwards-compatibility-breaking changes could be made.
Until 1.0.0, all versions of this project should be considered beta pre-releases.
A collection of useful, domain-specific and explicit predefined value-types for Kotlin & Java
Value types are immutable data objects that are compared and considered equal based on their values rather than their identity (reference). Additionally, they provide strong type-safety and domain-specific functions and helpers to build, use and transform their respoctive value. ValueTypes was inspired by Kotools Types and Scala's Opaque Types.
Type Safety: Prevent invalid states and accidental mutations
Clearer Domain Model: Express domain concepts precisely (e.g., FirstName, Age, IPv4Address)
Reduced Bugs: Immutability eliminates entire classes of concurrency and state-related bugs
Better Testing: Simpler to test due to their immutable nature
Performance: Optimized by the compiler through Kotlin's value class feature
Improved type-safety, compared to working with Strings:
val firstName: FirstName = FirstName.of("Jane")
val lastName: LastName = firstName // << compilation error
Additional, domain-specific checks:
// A LocalDate can be anything, a BirthDate must be in the past
IPv4Address.of("192.168.1.1").isSuccess // true, because it's a valid v4 IP
IPv4Address.of("192.168.1").isSuccess // false, just 3 octets
IPv4Address.of("300.168.1.1").isSuccess // false, because first octet is too big
IPv4Address.of("localhost").isSuccess // false, because hostname is not an IP
Useful helper functions & transformations:
val birthDate: Result<BirthDate> = BirthDate.of(1989, 09, 05)
birthDay.age // returns the age of the person, by comparing birth date to current year
val ip = IPv4Address.of("192.168.1.1")
ip.isPrivate // true, because 192.168.xxx.xxx is a private IP segment
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