JDI in Scala (Java Debug Interface)

JDIDemo.scala

// see http://wayne-adams.blogspot.fr/2011/10/generating-minable-event-stream-with.html
import scala.collection.JavaConversions.asScalaBuffer
import scala.collection.JavaConversions.asScalaIterator

import com.sun.jdi.connect.Connector
import com.sun.jdi.event.BreakpointEvent
import com.sun.jdi.request.BreakpointRequest
import com.sun.jdi.request.EventRequest
import com.sun.jdi.Bootstrap
import com.sun.jdi.StringReference

object JDIDemo extends App {
  val debugPort = args(0).toInt
  val lineNumber = args(1).toInt
  val varName = args(2)
  val vmMgr = Bootstrap.virtualMachineManager
  val socketConnector = vmMgr.attachingConnectors.find(_.transport.name == "dt_socket") match {
    case Some(c) => c
    case None => throw new Exception("not found : dt_socket")
  }
  val paramsMap = socketConnector.defaultArguments
  val portArg = paramsMap.get("port").asInstanceOf[Connector.IntegerArgument]
  portArg.setValue(debugPort)
  val vm = socketConnector.attach(paramsMap)
  println("Attached to process '" + vm.name + "'")
  val refTypes = vm.allClasses
  val breakpointLocations = for (r <- refTypes; l <- r.allLineLocations if l.lineNumber == lineNumber) yield l
  val breakpointLocation = breakpointLocations(0)
  val evtReqMgr = vm.eventRequestManager
  val bReq = evtReqMgr.createBreakpointRequest(breakpointLocation)
  bReq.setSuspendPolicy(EventRequest.SUSPEND_ALL)
  bReq.enable()
  val evtQueue = vm.eventQueue
  while (true) {
    val evtSet = evtQueue.remove()
    for (evt <- evtSet.eventIterator) {
      evt.request match {
        case bpReq: BreakpointRequest if bpReq.location.lineNumber == lineNumber =>

          System.out.println("Breakpoint at line " + lineNumber + ": ")
          val brEvt = evt.asInstanceOf[BreakpointEvent]
          val threadRef = brEvt.thread
          val stackFrame = threadRef.frame(0)
          for (visibleVar <- stackFrame.visibleVariables if (visibleVar.name == varName))
            stackFrame.getValue(visibleVar) match {
              case varNameValue: StringReference => println(varName + " = '" + varNameValue + "'")
            }
      }
    }
  }

}