CODEWITHSUNDEEP
javascalareflection
recalcitrant
recalcitrant

Reputation: 899

Pass an Array of arbitrary arguments to a method invoked via reflection

I need to create a function which creates a class from an arbitrary string and passes an array of parameters to a fixed method called "render". The problem is that depending on the class the "render" method may take a varying amount of arguments. Unfortunately the "render" method cannot be changed to accept varargs so I'm wondering if I can still pass the arguments as an Array?

This yields: "java.lang.IllegalArgumentException: wrong number of arguments"

Here's the code:

def perform(strClazz: String, pTypes: Array[Class[_]], params: Array[Object]) = {
  val clazz = MyClassLoader.loadClass(strClazz)
  val render = clazz.getDeclaredMethod("render", pTypes: _*)
  // params: java.lang.IllegalArgumentException: wrong number of arguments
  render.invoke(clazz, params)
}

And I call it via:

perform("MyClass",Array[Class[_]](classOf[String], classOf[String]),Array[Any]("first", "second"))

The invoked method takes two Strings as arguments so the following DOES work:

render.invoke(clazz, "first", "second")

Is it not possible to pass an Array then?

Upvotes: 0

Views: 484

Answers (1)

Viktor Klang
Viktor Klang

Reputation: 26579

scala> class Foo { def f(s: String, i: Int): Unit = () }
defined class Foo

scala> classOf[Foo].getDeclaredMethod("f", Array(classOf[String], classOf[Int]):_*)
res0: java.lang.reflect.Method = public void Foo.f(java.lang.String,int)

Upvotes: 2

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