Dynamically create an instance of a class using variable arguments.

create-dynamic-instance-with-varargs.scala

  /**
    * Create an instane of a class of type T with given arguments.
    *
    * @param args Arguments to create instance with. The order of arguments must match the constructor!
    * @tparam T Type of class to create.
    * @return Instance of T constructed with given arguments.
    */
  def createInstanceOf[T : reflect.runtime.universe.TypeTag](args: Any*): util.Try[T] = {
    import reflect.runtime.{universe => ru}

    // Runtime Mirror to be able to do reflection
    val mirror = ru.runtimeMirror(ReflectionUtil.getClass.getClassLoader)

    val clazz = ru.typeOf[T].typeSymbol.asClass

    val classMirror = mirror.reflectClass(clazz)

    // Expect a single constructor
    val constructor = ru.typeOf[T].decl(ru.termNames.CONSTRUCTOR).asMethod

    val constructorMethod = classMirror.reflectConstructor(constructor)

    util.Try {
      // create instance using constructors
      val instance = constructorMethod(args: _*)
      // need to cast to wanted type
      instance.asInstanceOf[T]
    }
  }