o#
# This combines the dynamic compilation of a Java class
# so as to use an R object as an implementation of a Java interface
# and also the dynamic callback to an R function.
#

library(SJava)
.JavaInit()

compiler <- .JavaConstructor("ForeignReferenceClassGenerator", "java.awt.event.ActionListener", "RButtonListener")
dyn <- .Java("__Evaluator","dynamicClassLoader")
.Java(dyn,"defineClass", compiler)

 btnCallback <- function(n = 0) {
   actionPerformed <- function(event) {
     n <<- n + 1
#     print(event)
     print(n)
   }
   return(list(actionPerformed=actionPerformed, count =function() n))
 }


gui = function(n = 0)
{
 b <- .JavaConstructor("javax.swing.JButton","Click me")
 f <- .JavaConstructor("GenericFrame", b, TRUE)

 cb <- btnCallback(n)
# ref <- foreignReference(cb, "btnCB")
 ref <- foreignReference(cb)

  # XXX problems if .convert is not specified here as the default
  # causes problems.
  # We get into the isRReference in s_from_java_basic
  # and then we end up with the wrong thing.
 l <- .JavaConstructor("RButtonListener", ref, .convert = FALSE)
print(l)
print(class(l))
 
.Java(b,"addActionListener", l)

 invisible(list(button = b, callback = cb))
}

# Then create two instances of the button setup
# but with different initial counter values.
#
# gui()
# gui(100)