From 8516613ad2ffd5b29f2e611a0a9e9006c5613ea4 Mon Sep 17 00:00:00 2001
From: Diego <diegolparra@gmail.com>
Date: Wed, 22 Jun 2016 15:32:23 -0300
Subject: + kamon-autoweave: add support Attach on IBM J9 and closes #354

---
 .../scala/kamon/autoweave/loader/AgentLoader.scala |  5 ++-
 .../autoweave/loader/AttachmentProviders.scala     | 41 ++++++++++++++++------
 kamon-core/src/main/scala/kamon/Kamon.scala        |  1 +
 3 files changed, 34 insertions(+), 13 deletions(-)

diff --git a/kamon-autoweave/src/main/scala/kamon/autoweave/loader/AgentLoader.scala b/kamon-autoweave/src/main/scala/kamon/autoweave/loader/AgentLoader.scala
index 2f26a39d..5f865cb3 100644
--- a/kamon-autoweave/src/main/scala/kamon/autoweave/loader/AgentLoader.scala
+++ b/kamon-autoweave/src/main/scala/kamon/autoweave/loader/AgentLoader.scala
@@ -99,10 +99,9 @@ object AgentLoader {
     AttachmentProviders.resolve() match {
       case Some(virtualMachine) ⇒
         val virtualMachineInstance = virtualMachine.getDeclaredMethod("attach", classOf[String]).invoke(null, getPidFromRuntimeMBean)
-        virtualMachine.getDeclaredMethod("loadAgent", classOf[String], classOf[String])
-          .invoke(virtualMachineInstance, generateAgentJar(agent, resources).getAbsolutePath, "")
+        virtualMachine.getDeclaredMethod("loadAgent", classOf[String], classOf[String]).invoke(virtualMachineInstance, generateAgentJar(agent, resources).getAbsolutePath, "")
         virtualMachine.getDeclaredMethod("detach").invoke(virtualMachineInstance)
-      case None ⇒ throw new RuntimeException(s"Error trying to use Attach API") with NoStackTrace
+      case None ⇒ throw new IllegalStateException("Cannot read the virtual machine type...") with NoStackTrace
     }
   }
 
diff --git a/kamon-autoweave/src/main/scala/kamon/autoweave/loader/AttachmentProviders.scala b/kamon-autoweave/src/main/scala/kamon/autoweave/loader/AttachmentProviders.scala
index ebb112e4..fff23735 100644
--- a/kamon-autoweave/src/main/scala/kamon/autoweave/loader/AttachmentProviders.scala
+++ b/kamon-autoweave/src/main/scala/kamon/autoweave/loader/AttachmentProviders.scala
@@ -17,13 +17,20 @@ package kamon.autoweave.loader
 
 import java.io.File
 import java.net.{ URL, URLClassLoader }
-import java.security.{ PrivilegedAction, AccessController }
+import java.security.{ AccessController, PrivilegedAction }
 
-object AttachmentProviders extends {
+import scala.util.control.NonFatal
+import scala.util.{ Failure, Success, Try }
 
-  val VirtualMachineTyeName = "com.sun.tools.attach.VirtualMachine"
+object AttachmentProviders {
 
   sealed trait AttachmentProvider {
+    def resolve(): Option[Class[_]]
+  }
+
+  trait DefaultAttachmentProvider extends AttachmentProvider {
+    val VirtualMachineTyeName = "com.sun.tools.attach.VirtualMachine"
+
     def toolsJarPath: String
 
     /**
@@ -34,17 +41,31 @@ object AttachmentProviders extends {
      */
     def resolve(): Option[Class[_]] = {
       val toolsJar = new File(System.getProperty("java.home").replace('\\', '/') + "/../" + toolsJarPath)
-      if (toolsJar.isFile && toolsJar.canRead)
-        Some(AccessController.doPrivileged(new ClassLoaderCreationAction(toolsJar)).loadClass(VirtualMachineTyeName))
-      else None
+      if (toolsJar.isFile && toolsJar.canRead) {
+        Try(AccessController.doPrivileged(new ClassLoaderCreationAction(toolsJar)).loadClass(VirtualMachineTyeName)) match {
+          case Success(vm)          ⇒ Some(vm)
+          case Failure(NonFatal(_)) ⇒ None
+        }
+      } else None
     }
   }
 
-  case object JVM extends AttachmentProvider { val toolsJarPath = "../lib/tools.jar" }
-  case object JDK extends AttachmentProvider { val toolsJarPath = "lib/tools.jar" }
-  case object MAC extends AttachmentProvider { val toolsJarPath = "../Classes/classes.jar" }
+  case object JVM extends DefaultAttachmentProvider { val toolsJarPath = "../lib/tools.jar" }
+  case object JDK extends DefaultAttachmentProvider { val toolsJarPath = "lib/tools.jar" }
+  case object MAC extends DefaultAttachmentProvider { val toolsJarPath = "../Classes/classes.jar" }
+  case object IBM extends AttachmentProvider {
+
+    val IBMVirtualMachineTyeName = "com.ibm.tools.attach.VirtualMachine"
+
+    override def resolve(): Option[Class[_]] = {
+      Try(ClassLoader.getSystemClassLoader.loadClass(IBMVirtualMachineTyeName)) match {
+        case Success(vm)          ⇒ Some(vm)
+        case Failure(NonFatal(_)) ⇒ None
+      }
+    }
+  }
 
-  private val providers = Seq(JVM, JDK, MAC)
+  private val providers = Seq(JVM, JDK, MAC, IBM)
 
   private final class ClassLoaderCreationAction(toolsJar: File) extends PrivilegedAction[ClassLoader] {
     override def run(): ClassLoader = new URLClassLoader(Array[URL](toolsJar.toURI.toURL), null)
diff --git a/kamon-core/src/main/scala/kamon/Kamon.scala b/kamon-core/src/main/scala/kamon/Kamon.scala
index 3f49845f..03b0de03 100644
--- a/kamon-core/src/main/scala/kamon/Kamon.scala
+++ b/kamon-core/src/main/scala/kamon/Kamon.scala
@@ -70,6 +70,7 @@ object Kamon {
         val color = (msg: String) ⇒ s"""\u001B[32m${msg}\u001B[0m"""
         log.info(color("Kamon-autoweave has been successfully loaded."))
         log.info(color("The AspectJ loadtime weaving agent is now attached to the JVM (you don't need to use -javaagent)."))
+        log.info(color("This offers extra flexibility but obviously any classes loaded before attachment will not be woven."))
       case Failure(NonFatal(reason)) ⇒ log.debug(s"Kamon-autoweave failed to load. Reason: ${reason.getMessage}.")
     }
   }
-- 
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