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Version: dev

Type Serialization

This page covers serialization of Kotlin-specific JVM types in native mode. For cross-language Kotlin models, use the xlang path described in Static Generated Serializers.

When compatible mode is enabled, Kotlin readers use the JVM compatible-read rules for selected scalar field type changes. A matched field can read between Boolean, String, numeric scalars, and java.math.BigDecimal when the converted value has the same logical value. For example, "true" and "false" can be read as booleans, "123" can be read as a numeric field that can hold 123, numbers and decimals can be read as canonical strings, and numeric widening or narrowing succeeds only when no precision or range is lost. Numeric strings use finite ASCII decimal syntax. Invalid strings and lossy conversions fail during deserialization. Nullable and boxed fields still compose with these conversions, but reference-tracked scalar type changes are incompatible.

Setup​

All examples assume the following setup:

import org.apache.fory.kotlin.ForyKotlin

val fory = ForyKotlin.builder().withXlang(false)
    .requireClassRegistration(false)
    .build()

Data Class​

data class Person(val name: String, val age: Int, val id: Long)

fory.register(Person::class.java)

val p = Person("John", 30, 1L)
println(fory.deserialize(fory.serialize(p)))

Unsigned Primitives​

Kotlin unsigned types are fully supported:

val uByte: UByte = 255u
val uShort: UShort = 65535u
val uInt: UInt = 4294967295u
val uLong: ULong = 18446744073709551615u

println(fory.deserialize(fory.serialize(uByte)))
println(fory.deserialize(fory.serialize(uShort)))
println(fory.deserialize(fory.serialize(uInt)))
println(fory.deserialize(fory.serialize(uLong)))

Unsigned Arrays​

val uByteArray = ubyteArrayOf(1u, 2u, 255u)
val uShortArray = ushortArrayOf(1u, 2u, 65535u)
val uIntArray = uintArrayOf(1u, 2u, 4294967295u)
val uLongArray = ulongArrayOf(1u, 2u, 18446744073709551615u)

println(fory.deserialize(fory.serialize(uByteArray)).contentToString())
println(fory.deserialize(fory.serialize(uShortArray)).contentToString())
println(fory.deserialize(fory.serialize(uIntArray)).contentToString())
println(fory.deserialize(fory.serialize(uLongArray)).contentToString())

Stdlib Types​

Pair and Triple​

val pair = Pair("key", 42)
val triple = Triple("a", "b", "c")

println(fory.deserialize(fory.serialize(pair)))
println(fory.deserialize(fory.serialize(triple)))

Result​

val success: Result<Int> = Result.success(42)
val failure: Result<Int> = Result.failure(Exception("error"))

println(fory.deserialize(fory.serialize(success)))
println(fory.deserialize(fory.serialize(failure)))

Ranges and Progressions​

val intRange = 1..10
val longRange = 1L..100L
val charRange = 'a'..'z'

println(fory.deserialize(fory.serialize(intRange)))
println(fory.deserialize(fory.serialize(longRange)))
println(fory.deserialize(fory.serialize(charRange)))

// Progressions
val intProgression = 1..10 step 2
val longProgression = 1L..100L step 10

println(fory.deserialize(fory.serialize(intProgression)))
println(fory.deserialize(fory.serialize(longProgression)))

Collections​

ArrayDeque​

val deque = ArrayDeque<String>()
deque.addFirst("first")
deque.addLast("last")

println(fory.deserialize(fory.serialize(deque)))

Empty Collections​

val emptyList = emptyList<String>()
val emptySet = emptySet<Int>()
val emptyMap = emptyMap<String, Int>()

println(fory.deserialize(fory.serialize(emptyList)))
println(fory.deserialize(fory.serialize(emptySet)))
println(fory.deserialize(fory.serialize(emptyMap)))

Duration​

import kotlin.time.Duration
import kotlin.time.Duration.Companion.hours
import kotlin.time.Duration.Companion.minutes

val duration: Duration = 2.hours + 30.minutes

println(fory.deserialize(fory.serialize(duration)))

Regex​

val regex = Regex("[a-zA-Z]+")

println(fory.deserialize(fory.serialize(regex)))

UUID (Kotlin 2.0+)​

import kotlin.uuid.Uuid

val uuid = Uuid.random()

println(fory.deserialize(fory.serialize(uuid)))

Types Working Out of the Box​

The following types work with the default Fory Java implementation:

  • Primitives: Byte, Boolean, Int, Short, Long, Char, Float, Double
  • String: String
  • Collections: ArrayList, HashMap, HashSet, LinkedHashSet, LinkedHashMap
  • Arrays: Array, BooleanArray, ByteArray, CharArray, DoubleArray, FloatArray, IntArray, LongArray, ShortArray

Use ForyKotlin.builder() for Kotlin-specific types such as unsigned values, ranges, and Duration.