KConstructorの取り出しを切り出し

Author: k163377

src/main/kotlin/com/mapk/core/Functions.kt

@@ -1,10 +1,13 @@
 package com.mapk.core
 
+import com.mapk.annotations.KConstructor
 import kotlin.reflect.KClass
 import kotlin.reflect.KFunction
 import kotlin.reflect.KParameter
 import kotlin.reflect.full.companionObject
 import kotlin.reflect.full.functions
+import kotlin.reflect.full.primaryConstructor
+import kotlin.reflect.jvm.jvmName
 
 inline fun <reified A : Annotation> KClass<*>.getAnnotatedFunctionsFromCompanionObject(): Pair<Any, List<KFunction<*>>>? {
     return this.companionObject?.let { companionObject ->
@@ -23,4 +26,25 @@ inline fun <reified A : Annotation, T> Collection<KFunction<T>>.getAnnotatedFunc
     return filter { function -> function.annotations.any { it is A } }
 }
 
+@Suppress("UNCHECKED_CAST")
+fun <T : Any> KClass<T>.getKConstructor(): Pair<Any?, KFunction<T>> {
+    val constructors = ArrayList<Pair<Any?, KFunction<T>>>()
+
+    this.getAnnotatedFunctionsFromCompanionObject<KConstructor>()?.let { (instance, functions) ->
+        functions.forEach {
+            constructors.add(instance to it as KFunction<T>)
+        }
+    }
+
+    this.constructors.getAnnotatedFunctions<KConstructor, T>().forEach {
+        constructors.add(null to it)
+    }
+
+    if (constructors.size == 1) return constructors.single()
+
+    if (constructors.isEmpty()) return null to this.primaryConstructor!!
+
+    throw IllegalArgumentException("${this.jvmName} has multiple ${KConstructor::class.jvmName}.")
+}
+
 fun KParameter.getKClass(): KClass<*> = type.classifier as KClass<*>