Konverter

Lightweight Kotlin library for painless and type-safe building and validation of immutable objects.

Features

• Simple and painless builders for immutable objects
• Explicit and flexible builders
• Lazy calculations
• Validation during building
• Validation and building errors aggregation
• Lightweight and minimal-dependency (only kotlin-stdlib and kotlin-reflect)

Setup

Full setup info

Add to repositories

Gradle

repositories {
    maven {
        url  "https://dl.bintray.com/yanislavcore/konverter" 
    }
}

Maven

<repositories>
    <repository>
        <snapshots>
            <enabled>false</enabled>
        </snapshots>
        <id>bintray-yanislavcore-konverter</id>
        <name>bintray</name>
        <url>https://dl.bintray.com/yanislavcore/konverter</url>
    </repository>
</repositories>

Add dependency

Gradle

compile 'org.yanislavcore:konverter:0.1.0'

Maven

<dependency>
  <groupId>org.yanislavcore</groupId>
  <artifactId>konverter</artifactId>
  <version>0.1.0</version>
</dependency>

Usage

import org.yanislavcore.konverter.Konverter
import org.yanislavcore.konverter.ValidationException
import java.math.BigDecimal
import java.util.*


data class BarData(val first: String, val second: UUID)
data class Foo(
    val bar1: String,
    val bar2: Int,
    val bar3: BigDecimal,
    val bar4: BarData,
    val bar5: BarData?
)

fun build(input: Map<String, String>): Foo = Konverter.convert {

    val bar1 = lazyMapping { input["bar1"] ?: invalid("'bar1' should be not null") }

    Foo::bar1 with bar1

    Foo::bar2 with bar1.mapRight {
        it.toIntOrNull() ?: invalid("'bar1' should be int")
    }

    Foo::bar3 with lazyMapping {
        val s = input["bar3"] ?: invalid("'bar3' should be not null")
        s.toBigDecimalOrNull() ?: invalid("'bar3' should be float number")
    }

    Foo::bar4 with Konverter.lazyConvert {
        BarData::first with lazyMapping { input["bar4"] ?: invalid("'bar4' should be not null") }
        BarData::second with just(UUID.randomUUID())
    }

    Foo::bar5 withNullable just(null as BarData?)
}

fun main() {
    val input = mapOf(
        "bar1" to "42",
        "bar3" to "27.123",
        "bar4" to "barfoo"
    )

    val result: Foo = build(input)
    assert(42 == result.bar2)
    assert(BigDecimal("27.123") == result.bar3)

    val invalidInput = input.minus("bar1")
    val failedResult: ValidationException? = try {
        build(invalidInput)
        null
    } catch (e: ValidationException) {
        e
    }

    assert(failedResult != null)
    assert(failedResult!!.reasons!!.first().message == "'bar1' should be not null")
}

Building

./gradlew clean build