test

hoge.scala

import java.lang.reflect.{Proxy, InvocationHandler, Method}

object Prototype {

	def clone[T](base:T, content:AnyRef)(implicit manifest:ClassManifest[T]):T = {
	
		val metaclass = manifest.erasure
		Proxy.newProxyInstance(metaclass.getClassLoader, Array(metaclass),
				new InvocationHandler {
					override def invoke(proxy:Object, method:Method, args:Array[Object]):Object = {
						val a = if(args != null) args else Array[Object]()
						val callee = content.getClass.getDeclaredMethod(method.getName, a.map(_ getClass):_*)							
						callee.setAccessible(true)
						callee.invoke(content, a:_*)
					}
				}).asInstanceOf[T]
	}

}

trait FooLike {
	def x:String
	def y:String
}

case class Foo(hoge:String, hige:String) extends FooLike

val a:FooLike = Foo("foo","bar")
var b = Prototype.clone(a, new {
	val x = "baz"
})

println(a.x +", "+ a.y)
println(b.x +", "+ b.y)