Make ConfigKeyNaming immutable

core/src/main/scala/configs/ConfigKeyNaming.scala

@@ -19,31 +19,55 @@ package configs
 import configs.ConfigUtil.splitWords
 import java.util.Locale
 
-trait ConfigKeyNaming[A] { self =>
+sealed trait ConfigKeyNaming[A] {
 
  def apply(field: String): Seq[String]
 
- def applyFirst(field: String): String = apply(field).head
+ def applyFirst(field: String): String
 
- def andThen(f: String => Seq[String]): ConfigKeyNaming[A] =
- field => self.apply(field).flatMap(f)
+ def andThen(f: String => Seq[String]): ConfigKeyNaming[A]
 
- def or(f: String => Seq[String]): ConfigKeyNaming[A] =
- field => (self.apply(field) ++ f(field)).distinct
+ def or(f: String => Seq[String]): ConfigKeyNaming[A]
 
  /**
  * Enable fail on parsing an object and there are superfluous keys in the config
  */
- def withFailOnSuperfluousKeys(): ConfigKeyNaming[A] = {
- failOnSuperfluousKeys = true
- this
- }
+ def withFailOnSuperfluousKeys: ConfigKeyNaming[A]
+
+ def failOnSuperfluousKeys: Boolean
 
- var failOnSuperfluousKeys: Boolean = false
 }
 
 object ConfigKeyNaming {
 
+ def apply[A](f: String => String): ConfigKeyNaming[A] =
+ apply(f.andThen(Seq(_)))
+
+ def apply[A](f: String => Seq[String])(implicit dummy: DummyImplicit): ConfigKeyNaming[A] =
+ new Impl(f, false).asInstanceOf[ConfigKeyNaming[A]]
+
+
+ private final class Impl(f: String => Seq[String], val failOnSuperfluousKeys: Boolean) extends ConfigKeyNaming[Nothing] {
+ self =>
+
+ def apply(field: String): Seq[String] =
+ f(field)
+
+ def applyFirst(field: String): String =
+ apply(field).head
+
+ def andThen(f: String => Seq[String]): ConfigKeyNaming[Nothing] =
+ new Impl(self.f.andThen(_.flatMap(f)), failOnSuperfluousKeys)
+
+ def or(f: String => Seq[String]): ConfigKeyNaming[Nothing] =
+ new Impl(field => (apply(field) ++ f(field)).distinct, failOnSuperfluousKeys)
+
+ def withFailOnSuperfluousKeys: ConfigKeyNaming[Nothing] =
+ new Impl(f, true)
+
+ }
+
+
  implicit def defaultNaming[A]: ConfigKeyNaming[A] =
  hyphenSeparated[A]
 
@@ -52,28 +76,28 @@ object ConfigKeyNaming {
  _identity.asInstanceOf[ConfigKeyNaming[A]]
 
  private[this] val _identity: ConfigKeyNaming[Any] =
- x => Seq(x)
+ ConfigKeyNaming(x => x)
 
 
  def hyphenSeparated[A]: ConfigKeyNaming[A] =
  _hyphenSeparated.asInstanceOf[ConfigKeyNaming[A]]
 
  private[this] val _hyphenSeparated: ConfigKeyNaming[Any] =
- x => Seq(splitWords(x).mkString("-").toLowerCase(Locale.ROOT))
+ ConfigKeyNaming(x => splitWords(x).mkString("-").toLowerCase(Locale.ROOT))
 
 
  def snakeCase[A]: ConfigKeyNaming[A] =
  _snakeCase.asInstanceOf[ConfigKeyNaming[A]]
 
  private[this] val _snakeCase: ConfigKeyNaming[Any] =
- x => Seq(splitWords(x).mkString("_").toLowerCase(Locale.ROOT))
+ ConfigKeyNaming(x => splitWords(x).mkString("_").toLowerCase(Locale.ROOT))
 
 
  def lowerCamelCase[A]: ConfigKeyNaming[A] =
  _lowerCamelCase.asInstanceOf[ConfigKeyNaming[A]]
 
  private[this] val _lowerCamelCase: ConfigKeyNaming[Any] =
- x => Seq(splitWords(x) match {
+ ConfigKeyNaming(x => splitWords(x) match {
  case Nil => ""
  case h :: t => (h.toLowerCase(Locale.ROOT) :: t.map(_.capitalize)).mkString
  })
@@ -83,6 +107,6 @@ object ConfigKeyNaming {
  _upperCamelCase.asInstanceOf[ConfigKeyNaming[A]]
 
  private[this] val _upperCamelCase: ConfigKeyNaming[Any] =
- x => Seq(splitWords(x).map(_.capitalize).mkString)
+ ConfigKeyNaming(x => splitWords(x).map(_.capitalize).mkString)
 
 }

core/src/test/scala/configs/instance/CaseClassTypesTest.scala

@@ -62,7 +62,7 @@ object CaseClassTypesTest extends Scalaprops {
  val failOnSuperfluousConfig = {
  implicit def myDefaultNaming[A]: ConfigKeyNaming[A] =
  ConfigKeyNaming.lowerCamelCase[A].or(ConfigKeyNaming.hyphenSeparated[A].apply)
- .withFailOnSuperfluousKeys()
+ .withFailOnSuperfluousKeys
  forAll {
  val reader = ConfigReader.derive[ComplexClass]
  val configStr = """
@@ -87,7 +87,7 @@ object CaseClassTypesTest extends Scalaprops {
  // generic default naming
  implicit def myDefaultNaming[A]: ConfigKeyNaming[A] =
  ConfigKeyNaming.hyphenSeparated[A].or(ConfigKeyNaming.lowerCamelCase[A].apply)
- .withFailOnSuperfluousKeys()
+ .withFailOnSuperfluousKeys
  forAll {
  val reader = ConfigReader.derive[TestSeal]
  val configStr = """
@@ -112,7 +112,7 @@ object CaseClassTypesTest extends Scalaprops {
  // generic default naming
  implicit def myDefaultNaming[A]: ConfigKeyNaming[A] =
  ConfigKeyNaming.hyphenSeparated[A].or(ConfigKeyNaming.lowerCamelCase[A].apply)
- .withFailOnSuperfluousKeys()
+ .withFailOnSuperfluousKeys
  forAll {
  val reader = ConfigReader.derive[TestSeal]
  val configStr = """
@@ -133,7 +133,7 @@ object CaseClassTypesTest extends Scalaprops {
  // generic default naming
  implicit def myDefaultNaming[A]: ConfigKeyNaming[A] =
  ConfigKeyNaming.hyphenSeparated[A].or(ConfigKeyNaming.lowerCamelCase[A].apply)
- .withFailOnSuperfluousKeys()
+ .withFailOnSuperfluousKeys
  forAll {
  val reader = ConfigReader.derive[TestClass]
  val configStr = """
@@ -159,7 +159,7 @@ object CaseClassTypesTest extends Scalaprops {
  // generic default naming
  implicit def myDefaultNaming[A]: ConfigKeyNaming[A] =
  ConfigKeyNaming.hyphenSeparated[A].or(ConfigKeyNaming.lowerCamelCase[A].apply)
- .withFailOnSuperfluousKeys()
+ .withFailOnSuperfluousKeys
  forAll {
  val reader = ConfigReader.derive[TestClass]
  val configStr = """