Correct fix for Issue #169 - do not assume that "update" event contai…

…ns full information about the changes.

The documentation for the "update" event does not state that there is information about the content that changes, only its location (from, to).
It cannot be assumed that `getAddedSubList` contains the update. The behaviour changed between JavaFX 2 and 8.
Provide fix that is in line with JavaFX 2 documantation but also works in JavaFX 8, so there are no uncessary diferences between versions.

scalafx/src/main/scala/scalafx/collections/ObservableBuffer.scala

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2011-2014, ScalaFX Project
+ * Copyright (c) 2011-2015, ScalaFX Project
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -134,13 +134,13 @@ object ObservableBuffer extends SeqFactory[ObservableBuffer] {
   /**
    * Indicates an Update in an $OB.
    *
-   * @param position Position from where new elements were updated
-   * @param updated elements updated
+   * @param from Position from where elements were updated
+   * @param to Position to where elements were updated (exclusive)
    * @see [[http://docs.oracle.com/javafx/2/api/javafx/collections/ListChangeListener.Change.html#wasUpdated() `ListChangeListener.Change.wasUpdated()`]]
    * @see [[http://docs.oracle.com/javafx/2/api/javafx/collections/ListChangeListener.Change.html#getFrom() `ListChangeListener.Change.getFrom()`]]
-   * @see [[http://docs.oracle.com/javafx/2/api/javafx/collections/ListChangeListener.Change.html#getAddedSubList() `ListChangeListener.Change.getAddedSubList()`]]
+   * @see [[http://docs.oracle.com/javafx/2/api/javafx/collections/ListChangeListener.Change.html#getTo() `ListChangeListener.Change.getTo()`]]
    */
-  case class Update[T](position: Int, updated: Traversable[T]) extends Change
+  case class Update[T](from: Int, to: Int) extends Change
 
 
   // CHANGING INDICATORS - END
@@ -567,7 +567,7 @@ class ObservableBuffer[T](override val delegate: jfxc.ObservableList[T] = jfxc.F
               x => c.getPermutation(x)
             })
           } else if (c.wasUpdated()) {
-            changes += Update(c.getFrom, c.getAddedSubList)
+            changes += Update(c.getFrom, c.getTo)
           } else {
             if (c.wasRemoved()) {
               changes += Remove(c.getFrom, c.getRemoved)

scalafx/src/test/scala/scalafx/collections/ObservableBufferSpec.scala

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2011-2014, ScalaFX Project
+ * Copyright (c) 2011-2015, ScalaFX Project
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -642,34 +642,25 @@ class ObservableBufferSpec[T]
 
     items.append(jfxc.FXCollections.observableArrayList("test"))
 
-    var expectedPosition = -1
+    var actualFrom = -1
+    var actualTo = -1
     var changed = false
     items.onChange((obs, changes) => {
       changed = true
       for (change <- changes)
         change match {
-          case ObservableBuffer.Update(position, update) =>
-            position should be(expectedPosition)
-            val list = update.toList
-            list.length should equal(1)
-            list(0) match {
-              case e: ElementType =>
-                e.length should equal(2)
-                e(0) should equal("test")
-                e(1) should equal("update")
-              case _@t            => fail("Wrong list type: " + t)
-            }
-
+          case ObservableBuffer.Update(from, to) =>
+            actualFrom = from
+            actualTo = to
           case _@otherChange => fail("Wrong change: " + otherChange.toString)
         }
     })
 
-    expectedPosition = 0
     items(0) += "update"
 
     changed should be(true)
-
-
+    actualFrom should be(0)
+    actualTo should be(1)
   }
 
 }