Type-safe wrappers for primitive and comparable values, preventing accidental mixing at compile time; includes extension helpers, serialization, JPA/Hibernate, QueryDSL, Spring and Elasticsearch integrations.
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Type-Safe Values for Kotlin
A lightweight Kotlin Multiplatform library providing type-safe wrappers for primitive values, preventing accidental mixing of incompatible values at compile time.
📖 Documentation | 🐙 GitHub
Comparable typeThe BOM (Bill of Materials) lets you declare a single versioned dependency and omit versions on individual modules:
dependencies {
implementation(platform("com.ekino.oss:typed-value-bom:1.3.4"))
implementation("com.ekino.oss:typed-value-core")
// Optional integrations — no version needed
implementation("com.ekino.oss:typed-value-jackson")
implementation("com.ekino.oss:typed-value-spring")
}
dependencies {
implementation("com.ekino.oss:typed-value-core:1.3.4")
// Optional integrations
implementation("com.ekino.oss:typed-value-jackson:1.3.4")
implementation("com.ekino.oss:typed-value-spring:1.3.4")
}
import com.ekino.oss.typedvalue.*;
TypedString<User> userId = TypedValues.typedString("user-123", User.class);
TypedLong<Product> productId = TypedValues.typedLong(42L, Product.class);
TypedUuid<Order> orderId = TypedValues.typedUuid(UUID.randomUUID(), Order.class);
@Configuration
class JacksonConfig {
@Bean
fun typedValueModule() = TypedValueModule()
}
data class UserDto(val id: TypedString<User>, val name: String)
val json = objectMapper.writeValueAsString(UserDto("user-123".toTypedString(), "Alice"))
// {"id":"user-123","name":"Alice"}
Register custom TypedValue subtypes for JSON serialization/deserialization:
Kotlin:
class TypedId<T : Any>(id: String, type: KClass<T>) : TypedString<T>(id, type)
@Configuration
class JacksonConfig {
@Bean
fun typedValueModule() = TypedValueModule().apply {
registerCustomTypedValue<TypedId<*>, String> { value, entityKClass ->
TypedId(value, entityKClass)
}
}
}
// Use in DTOs
( id: TypedId<User>, name: String)
Java:
Key points:
List<TypedId<User>>)Auto-configured when typed-value-spring is on the classpath.
@GetMapping("/users/{id}")
fun getUser(@PathVariable id: TypedString<User>): UserDto {
return userService.findById(id)
}
val qUser = QUser.user
val userIdExpr = qUser.typedValueExpressionOf { it._id }
queryFactory.selectFrom(qUser)
.where(userIdExpr.eq(userId))
.fetch()
@Configuration
class ElasticsearchConfig : ElasticsearchConfigurationSupport() {
@Bean
override fun elasticsearchMappingContext() = TypedValueElasticsearchMappingContext()
}
@Document(indexName = "users")
data class UserDocument(
val id: TypedString<User>,
val friendIds: List<TypedString<User>> // Collections supported (Lists only)
)
val userId = "user-123".toTypedString<User>()
// Type checking
userId.isAboutType<User>() // true
// Safe casting
val casted: TypedString<User>? = someId.takeIfAboutType<String, User>()
// Sorting
val sorted = listOf(userId1, userId2, userId3).sorted()
./gradlew build # Build all
./gradlew test # Run all tests
./gradlew spotlessApply # Format code
./gradlew typed-value-core:jvmTest # Test JVM only
./gradlew typed-value-core:jsTest # Test JS only
Copyright © 2025 Ekino
| Module | Description | Platforms |
|---|
typed-value-core | Core TypedValue interface | JVM, JS, Native |
typed-value-jackson | Jackson serialization | JVM |
typed-value-spring | Spring MVC converters | JVM |
typed-value-hibernate | JPA/Hibernate abstract entities & converters | JVM |
typed-value-querydsl | QueryDSL support (expressions + Q-classes for Hibernate entities) | JVM |
typed-value-spring-data-elasticsearch | Elasticsearch mapping | JVM |
import com.ekino.oss.typedvalue.*
// Type-safe identifiers
data class User(val id: TypedString<User>, val name: String)
data class Product(val id: TypedLong<Product>, val price: BigDecimal)
// Type-safe quantities
class Banana
class Apple
val bananas = 5.toTypedInt<Banana>()
val apples = 3.toTypedInt<Apple>()
// Type-safe money
class Cents
val price = 1999L.toTypedLong<Cents>()
// Create using extension functions
val userId = "user-123".toTypedString<User>()
val productId = 42L.toTypedLong<Product>()
// Type safety prevents mixing values
fun deleteUser(id: TypedString<User>) { /* ... */ }
deleteUser(userId) // ✅ Compiles
deleteUser(productId) // ❌ Compile error!
fun addBananas(count: TypedInt<Banana>) { /* ... */ }
addBananas(bananas) // ✅ Compiles
addBananas(apples) // ❌ Compile error!
| Type | Value Type | Platforms | Use Cases |
|---|
TypedString<T> | String | All | IDs, emails, codes |
TypedInt<T> | Int | All | Quantities, small counts |
TypedLong<T> | Long | All | Large IDs, money (cents) |
TypedUuid<T> | UUID | JVM only | Distributed IDs |
TypedValue<V, T> | Any Comparable | All | Custom types |
public class TypedId<T> extends TypedString<T> {
public TypedId(String id, KClass<T> type) {
super(id, type);
}
}
class JacksonConfig {
public TypedValueModule typedValueModule() {
TypedValueModule module = new TypedValueModule();
module.registerCustomTypedValue(
TypedId.class,
String.class,
(value, entityClass) -> new TypedId<>(
value,
JvmClassMappingKt.getKotlinClass(entityClass)
)
);
return module;
}
}
// Use abstract entity classes for automatic equals/hashCode
class User : AbstractUuidEntity<User>(User::class) {
var name: String? = null
}
// Or use HibernateEntityUtils for custom entities
class Product {
private var _id: Long? = null
var id: TypedLong<Product>?
get() = _id?.toTypedLong()
set(value) { _id = value?.value }
override fun equals(other: Any?) = HibernateEntityUtils.entityEquals(this, other) { it.id }
override fun hashCode() = HibernateEntityUtils.entityHashCode(this)
}