utils for accessing field & methods that are private in the scala repl via reflection

reflector.scala

/* For example, I want to do this:
 *
 * sqlContext.catalog.client.getTable("default", "blah").properties
 *
 * but none of that is public to me in the shell.  Using this, I can now do:
 *
 * sqlContext.reflectField("catalog").reflectField("client").reflectMethod("getTable", Seq("default", "blah")).reflectField("properties")
 *
 * not perfect, but usable.
 */


import java.lang.reflect.{Field, Method}

def _methods(cls:Class[_]): Seq[Method] = {
  if (cls == null) Seq()
  else cls.getDeclaredMethods() ++ _methods(cls.getSuperclass())
}

def methods(obj: Any): Seq[String] = {
  _methods(obj.getClass()).map(_.getName()).sorted
}

def _fields(cls: Class[_]): Seq[Field] = {
  if (cls == null) Seq()
  else cls.getDeclaredFields() ++ _fields(cls.getSuperclass())
}

def fields(obj: Any): Seq[String] = {
  _fields(obj.getClass()).map(_.getName()).sorted
}

def clzFindMethod(clz: Class[_], name:String): Method = {
  // TODO: handle scala's name munging, eg. org$apache$spark$sql$hive$HiveExternalCatalog$$makeQualified
  val method = _methods(clz).find(_.getName() == name).get
  method.setAccessible(true)
  method
}

def findMethod(obj: Any, name:String): Method = {
  // TODO: handle scala's name munging, eg. org$apache$spark$sql$hive$HiveExternalCatalog$$makeQualified
  clzFindMethod(obj.getClass(), name)
}

def get(obj: Any, name:String): Any = {
  val clz = obj.getClass()
  _fields(clz).find(_.getName() == name) match {
    case Some(f) =>
      f.setAccessible(true)
      f.get(obj)
    case None =>
      val m = findMethod(obj, name)
      m.invoke(obj)
  }
}

def showFields(obj: Any): Unit = {
  fields(obj).foreach{println}
}

def showMethods(obj: Any): Unit = {
  methods(obj).foreach{println}
}

implicit class StaticReflect(clz: Class[_]) {
  def reflectMethod(name: String, args: Seq[Object]): Any = {
    clzFindMethod(clz, name).invoke(null, args: _*)
  }
}

implicit class Reflector(obj: Any) {
  // TODO error msgs
  def reflectField(name: String): Any = {
    get(obj, name)
  }
  
  def reflectMethod(name: String, args: Seq[Object]): Any = {
    findMethod(obj,name).invoke(obj, args: _*)
  }
}