config4k/config4k: A Kotlin wrapper for Typesafe Config

原作者: [db:作者] 来自: 网络收藏邀请

开源软件名称（OpenSource Name）：

config4k/config4k

开源软件地址(OpenSource Url)：

https://github.com/config4k/config4k

开源编程语言(OpenSource Language)：

Kotlin 100.0%

开源软件介绍(OpenSource Introduction)：

Config4k

Config for Kotlin.

Config4k is a lightweight Typesafe Config wrapper for Kotlin and inspired by ficus, providing simple extension functions Config.extract<T> and Any.toConfig to convert between Config and Kotlin Objects.

Installation
Usage
Supported types
Contribute

Installation

Gradle:

repositories {
    mavenCentral()
}


dependencies {
    compile 'io.github.config4k:config4k:xxx' // See the `Download` badge
}

Usage

Delegated Properties

By far the simplest way to use config4k is via Kotlin Delegated Properties:

val config = ConfigFactory.parseString("""
                                          |stringValue = hello
                                          |booleanValue = true
                                          |""".trimMargin())

val stringValue: String by config
println(stringValue) // hello

val nullableStringValue: String? by config
println(nullableStringValue) // null

val booleanValue: Boolean by config
println(booleanValue) // true

Deserialization

Config.extract<T> converts Config to T.

Map

Maps can be serialized with String keys

val config = ConfigFactory.parseString("""
                                          |map {  
                                          |  foo = 5
                                          |  bar = 6
                                          |}""".trimMargin())
val map: Map<String, Int> = config.extract<Map<String, Int>>("map")
println(map["foo"] == 5) // true
println(map["bar"] == 6) // true

or with arbitrary keys

val config = ConfigFactory.parseString("""
                                          |map = [{  
                                          |  key = 5
                                          |  value = "foo"
                                          |}
                                          |{
                                          |  key = 6
                                          |  value = "bar"
                                          |}]""".trimMargin())
val map: Map<Int, String> = config.extract<Map<Int, String>>("map")
println(map[5] == "foo") // true
println(map[6] == "bar") // true

Test Class: TestMap.kt

Data Classes

Config4k has no option to use different names between code and config file.

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

val config = ConfigFactory.parseString("""
                                          |key {  
                                          |  name = "foo"
                                          |  age = 20
                                          |}""".trimMargin())
val person: Person = config.extract<Person>("key")
println(person.name == "foo") // true
println(person.age == 20) // true

For more details, please see TestArbitraryType.kt

Nullable

Using extract<T?> is the better way than Config.hasPath(). extract<T?> returns T when the path exists and null when it does not exist.

val config = ConfigFactory.parseString("""key = 10""")
val key = config.extract<Int?>("key")
val foo = config.extract<Int?>("foo")
println(key == 10) // true
println(foo == null) // true

Test Class: TestNullable.kt

Enum

Config4k also supports Enum. Enum is converted to String of its name in the config file.

enum class Size {
    SMALL,
    MEDIUM,
    LARGE
}

val config = ConfigFactory.parseString("""key = SMALL""")
val small = config.extract<Size>("key")
println(small == Size.SMALL) // true

Test Class: TestEnum.kt

Serialization

Any.toConfig converts the receiver object to Config.

String

You can use ConfigValue.render() to serialize Config. Config4k helps getting Config of the class you want to serialize.

data class Person(val name: String, val age: Int)
val person = Person("foo", 20).toConfig("person")
println(person.root().render())

Output:

{
    # hardcoded value
    "person" : {
        # hardcoded value
        "age" : 20,
        # hardcoded value
        "name" : "foo"
    }
}

Test Class: TestToConfigForArbitraryType.kt

ConfigRenderOptions

Typesafe Config's class ConfigRenderOptions is the argument of ConfigValue.render.

// If setJson(false) is called, ConfigValue.render returns HOCON
data class Person(val name: String, val age: Int)
val person = Person("foo", 20).toConfig("person")
val options = ConfigRenderOptions.defaults().setJson(false)
println(person.root().render(options))

Output:

    # hardcoded value
person {
    # hardcoded value
    age=20
    # hardcoded value
    name=foo
}

// setOriginComments(false) removes comments
data class Person(val name: String, val age: Int)
val person = Person("foo", 20).toConfig("person")
val options = ConfigRenderOptions.defaults()
                        .setJson(false)
                        .setOriginComments(false)
println(person.root().render(options))

Output:

person {
    age=20
    name=foo
}

Supported types

Property delegation, extract and toConfig support these types:

Primitive types
- Boolean
- Byte
- Int
- Long
- Float
- Double
String
import java.io.File
import java.nio.file.Path
java.time.Duration
java.time.Period
java.time.temporal.TemporalAmount
kotlin.text.Regex
Collections
- List
- Set
- Map<K, V>
- Array<T> (You can use Array<Int>, but can't use Array<Array<Int>>)
Nullable T?
Typesafe Config classes(Calling toConfig is meaningless)
- com.typesafe.config.Config
- com.typesafe.config.ConfigValue
- com.typesafe.config.ConfigMemorySize
Enum
Data classes