Cleanup, removing some obsolete methods

svn changeset:11227/svn branch:6.3_dd

10 files changed, 216 insertions, 211 deletions

diff --git a/src/com/vaadin/terminal/gwt/client/ui/VScrollTable.java b/src/com/vaadin/terminal/gwt/client/ui/VScrollTable.java
index 88e8da5147..f878dbd954 100644
--- a/src/com/vaadin/terminal/gwt/client/ui/VScrollTable.java
+++ b/src/com/vaadin/terminal/gwt/client/ui/VScrollTable.java
@@ -2502,7 +2502,7 @@ public class VScrollTable extends FlowPanel implements Table, ScrollHandler {
                             if (mDown && dragmode != 0) {
                                 VTransferable transferable = new VTransferable();
                                 transferable.setComponent(VScrollTable.this);
-                                transferable.setItemId("" + rowKey);
+                                transferable.setData("itemId", "" + rowKey);
 
                                 // TODO propertyId
                                 VDragEvent ev = VDragAndDropManager.get()
diff --git a/src/com/vaadin/terminal/gwt/client/ui/VTree.java b/src/com/vaadin/terminal/gwt/client/ui/VTree.java
index dd91fcdcea..a9db71d83e 100644
--- a/src/com/vaadin/terminal/gwt/client/ui/VTree.java
+++ b/src/com/vaadin/terminal/gwt/client/ui/VTree.java
@@ -25,7 +25,6 @@ import com.vaadin.terminal.gwt.client.MouseEventDetails;
 import com.vaadin.terminal.gwt.client.Paintable;
 import com.vaadin.terminal.gwt.client.UIDL;
 import com.vaadin.terminal.gwt.client.Util;
-import com.vaadin.terminal.gwt.client.ValueMap;
 import com.vaadin.terminal.gwt.client.ui.dd.VAbstractDropHandler;
 import com.vaadin.terminal.gwt.client.ui.dd.VAcceptCallback;
 import com.vaadin.terminal.gwt.client.ui.dd.VDragAndDropManager;
@@ -33,7 +32,6 @@ import com.vaadin.terminal.gwt.client.ui.dd.VDragEvent;
 import com.vaadin.terminal.gwt.client.ui.dd.VDropHandler;
 import com.vaadin.terminal.gwt.client.ui.dd.VHasDropHandler;
 import com.vaadin.terminal.gwt.client.ui.dd.VTransferable;
-import com.vaadin.terminal.gwt.client.ui.dd.VDragAndDropManager.DragEventType;
 
 /**
  * 
@@ -214,6 +212,7 @@ public class VTree extends FlowPanel implements Paintable, VHasDropHandler {
 
                 @Override
                 protected void dragAccepted(final VDragEvent drag) {
+
                 }
 
                 @Override
@@ -234,32 +233,15 @@ public class VTree extends FlowPanel implements Paintable, VHasDropHandler {
                         ApplicationConnection.getConsole().log(
                                 "Change in Transferable " + currentMouseOverKey
                                         + " " + detail);
-                        VAcceptCallback accpectedCb = new VAcceptCallback() {
-                            public void handleResponse(ValueMap responseData) {
-                                if (responseData == null // via client
-                                        // side
-                                        // validation
-                                        || responseData.containsKey("accepted")) {
-                                    keyToNode.get(currentMouseOverKey)
-                                            .emphasis(detail);
-                                }
-                            }
-                        };
-                        if (validateOnServer()) {
-                            VDragAndDropManager.get().visitServer(
-                                    DragEventType.OVER, accpectedCb);
-
-                        } else {
-                            if (validates(currentDrag)) {
-                                accpectedCb.handleResponse(null);
-                            } else {
+                        validate(new VAcceptCallback() {
+                            public void accepted() {
                                 keyToNode.get(currentMouseOverKey).emphasis(
-                                        null);
-                            }
-                            if (oldIdOver != null
-                                    && oldIdOver != currentMouseOverKey) {
-                                keyToNode.get(oldIdOver).emphasis(null);
+                                        detail);
                             }
+                        }, currentDrag);
+                        if (oldIdOver != null
+                                && oldIdOver != currentMouseOverKey) {
+                            keyToNode.get(oldIdOver).emphasis(null);
                         }
                     }
 
@@ -451,7 +433,7 @@ public class VTree extends FlowPanel implements Paintable, VHasDropHandler {
                         // start actual drag on slight move when mouse is down
                         VTransferable t = new VTransferable();
                         t.setComponent(VTree.this);
-                        t.setItemId(key);
+                        t.setData("itemId", key);
                         VDragEvent drag = VDragAndDropManager.get().startDrag(
                                 t, mouseDownEvent, true);
 
diff --git a/src/com/vaadin/terminal/gwt/client/ui/dd/VAbstractDropHandler.java b/src/com/vaadin/terminal/gwt/client/ui/dd/VAbstractDropHandler.java
index 42602dd3be..2fe69101d8 100644
--- a/src/com/vaadin/terminal/gwt/client/ui/dd/VAbstractDropHandler.java
+++ b/src/com/vaadin/terminal/gwt/client/ui/dd/VAbstractDropHandler.java
@@ -1,33 +1,36 @@
 package com.vaadin.terminal.gwt.client.ui.dd;
 
+import com.vaadin.event.AbstractDropHandler;
+import com.vaadin.event.DropTarget;
+import com.vaadin.event.Transferable;
+import com.vaadin.event.AbstractDropHandler.AcceptCriterion;
 import com.vaadin.terminal.gwt.client.Paintable;
 import com.vaadin.terminal.gwt.client.UIDL;
-import com.vaadin.terminal.gwt.client.ValueMap;
-import com.vaadin.terminal.gwt.client.ui.dd.VDragAndDropManager.DragEventType;
 
 public abstract class VAbstractDropHandler implements VDropHandler {
 
-    private boolean serverValidate;
+    private boolean mustValidateOnServer = true;
     private UIDL criterioUIDL;
 
+    /**
+     * Implementor/user of {@link VAbstractDropHandler} must pass the UIDL
+     * painted by {@link AbstractDropHandler} (the server side counterpart) to
+     * this method. Practically the details about {@link AcceptCriterion} are
+     * saved.
+     * 
+     * @param uidl
+     */
     public void updateRules(UIDL uidl) {
-        serverValidate = uidl.getBooleanAttribute("serverValidate");
+        mustValidateOnServer = uidl.getBooleanAttribute("serverValidate");
         int childCount = uidl.getChildCount();
         for (int i = 0; i < childCount; i++) {
             UIDL childUIDL = uidl.getChildUIDL(i);
             if (childUIDL.getTag().equals("acceptCriterion")) {
                 criterioUIDL = childUIDL;
-                // TODO consider parsing the criteria tree here instead of
-                // translating uidl during validates()
-
             }
         }
     }
 
-    public boolean validateOnServer() {
-        return serverValidate;
-    }
-
     /**
      * Default implementation does nothing.
      */
@@ -36,42 +39,61 @@ public abstract class VAbstractDropHandler implements VDropHandler {
     }
 
     /**
-     * Default implementation does nothing.
+     * Default implementation does nothing. Implementors should clean possible
+     * emphasis or drag icons here.
      */
     public void dragLeave(VDragEvent drag) {
-        // TODO Auto-generated method stub
 
     }
 
     /**
+     * The default implementation in {@link VAbstractDropHandler} checks if the
+     * Transferable is accepted.
+     * <p>
      * If transferable is accepted (either via server visit or client side
-     * rules) the default implementation calls {@link #dragAccepted(VDragEvent)}
-     * method.
+     * rules) the default implementation calls abstract
+     * {@link #dragAccepted(VDragEvent)} method.
+     * <p>
+     * If drop handler has distinct places where some parts may accept the
+     * {@link Transferable} and others don't, one should use similar validation
+     * logic in dragOver method and replace this method with empty
+     * implementation.
+     * 
      */
     public void dragEnter(final VDragEvent drag) {
-        if (serverValidate) {
-            VDragAndDropManager.get().visitServer(DragEventType.ENTER,
-                    new VAcceptCallback() {
-                        public void handleResponse(ValueMap responseData) {
-                            if (responseData.containsKey("accepted")) {
-                                dragAccepted(drag);
-                            }
-                        }
-                    });
-        } else if (validates(drag)) {
-            dragAccepted(drag);
-        }
+        validate(new VAcceptCallback() {
+            public void accepted() {
+                dragAccepted(drag);
+            }
+        }, drag);
     }
 
+    /**
+     * This method is called when a valid drop location was found with
+     * {@link AcceptCriterion} either via client or server side check.
+     * <p>
+     * Implementations can set some hints for users here to highlight that the
+     * drag is on a valid drop location.
+     * 
+     * @param drag
+     */
     abstract protected void dragAccepted(VDragEvent drag);
 
+    protected void validate(VAcceptCallback cb, VDragEvent event) {
+        if (mustValidateOnServer) {
+            VDragAndDropManager.get().visitServer(cb);
+        } else if (validateOnClient(event)) {
+            cb.accepted();
+        }
+    }
+
     /**
      * Returns true if client side rules are met.
      * 
      * @param drag
      * @return
      */
-    protected boolean validates(VDragEvent drag) {
+    protected boolean validateOnClient(VDragEvent drag) {
         if (criterioUIDL != null) {
             String criteriaName = criterioUIDL.getStringAttribute("name");
             VAcceptCriteria acceptCriteria = VAcceptCriterion.get(criteriaName);
@@ -84,14 +106,24 @@ public abstract class VAbstractDropHandler implements VDropHandler {
         return false;
     }
 
+    /**
+     * The default implemmentation visits server if {@link AcceptCriterion} 
+     * can't be verified on client or if {@link AcceptCriterion} are met on
+     * client.
+     */
     public boolean drop(VDragEvent drag) {
-        if (serverValidate) {
+        if (mustValidateOnServer) {
             return true;
         } else {
-            return validates(drag);
+            return validateOnClient(drag);
         }
     }
 
+    /**
+     * Returns the Paintable who owns this {@link VAbstractDropHandler}. Server
+     * side counterpart of the Paintable is expected to implement
+     * {@link DropTarget} interface.
+     */
     public abstract Paintable getPaintable();
 
 }
diff --git a/src/com/vaadin/terminal/gwt/client/ui/dd/VAcceptCallback.java b/src/com/vaadin/terminal/gwt/client/ui/dd/VAcceptCallback.java
index 2366105853..6c47604ea4 100644
--- a/src/com/vaadin/terminal/gwt/client/ui/dd/VAcceptCallback.java
+++ b/src/com/vaadin/terminal/gwt/client/ui/dd/VAcceptCallback.java
@@ -1,19 +1,15 @@
 package com.vaadin.terminal.gwt.client.ui.dd;
 
-import com.vaadin.terminal.gwt.client.ValueMap;
 
 public interface VAcceptCallback {
 
     /**
      * This method is called by {@link VDragAndDropManager} if the
      * {@link VDragEvent} is still active. Developer can update for example drag
-     * icon or target emphasis based on the information returned from server
-     * side. If the drag and drop operation ends or the
-     * {@link VAbstractDropHandler} has changed before response arrives, the
-     * method is never called.
-     * 
-     * @param responseData
+     * icon or empahsis the target if the target accepts the transferable. If
+     * the drag and drop operation ends or the {@link VAbstractDropHandler} has
+     * changed before response arrives, the method is never called.
      */
-    public void handleResponse(ValueMap responseData);
+    public void accepted();
 
 }
diff --git a/src/com/vaadin/terminal/gwt/client/ui/dd/VAcceptCriterion.java b/src/com/vaadin/terminal/gwt/client/ui/dd/VAcceptCriterion.java
index f1b6d2de34..fe251df4e9 100644
--- a/src/com/vaadin/terminal/gwt/client/ui/dd/VAcceptCriterion.java
+++ b/src/com/vaadin/terminal/gwt/client/ui/dd/VAcceptCriterion.java
@@ -5,6 +5,9 @@ import java.util.Map;
 
 import com.google.gwt.core.client.GWT;
 
+/**
+ * A class via all AcceptCriteria instances are fetched by an identifier.
+ */
 public class VAcceptCriterion {
     protected static Map<String, VAcceptCriteria> criterion = new HashMap<String, VAcceptCriteria>();
     private static VAcceptCriterionImpl impl;
diff --git a/src/com/vaadin/terminal/gwt/client/ui/dd/VAcceptCriterionImpl.java b/src/com/vaadin/terminal/gwt/client/ui/dd/VAcceptCriterionImpl.java
index e2cd4b6a5b..7f93dfa149 100644
--- a/src/com/vaadin/terminal/gwt/client/ui/dd/VAcceptCriterionImpl.java
+++ b/src/com/vaadin/terminal/gwt/client/ui/dd/VAcceptCriterionImpl.java
@@ -62,14 +62,14 @@ public class VAcceptCriterionImpl {
 
     private final class HasItemId implements VAcceptCriteria {
         public boolean accept(VDragEvent drag, UIDL configuration) {
-            return drag.getTransferable().getItemId() != null;
+            return drag.getTransferable().getData("itemId") != null;
         }
     }
 
     /**
-     * TODO this method could be written by generator
+     * TODO this class/method must be written by generator
      * 
-     * TODO consider moving implementations to top level classes
+     * TODO move implementations to top level classes.
      * 
      * TODO use fully qualified names of server side counterparts as keys
      */
diff --git a/src/com/vaadin/terminal/gwt/client/ui/dd/VDragAndDropManager.java b/src/com/vaadin/terminal/gwt/client/ui/dd/VDragAndDropManager.java
index 4a302b3f4d..6382147634 100644
--- a/src/com/vaadin/terminal/gwt/client/ui/dd/VDragAndDropManager.java
+++ b/src/com/vaadin/terminal/gwt/client/ui/dd/VDragAndDropManager.java
@@ -228,6 +228,12 @@ public class VDragAndDropManager {
     private NativePreviewHandler defaultDragAndDropEventHandler = new DefaultDragAndDropEventHandler();
 
     /**
+     * Flag to indicate if drag operation has really started or not. Null check
+     * of currentDrag field is not enough as a lazy start may be pending.
+     */
+    private boolean isStarted;
+
+    /**
      * This method is used to start Vaadin client side drag and drop operation.
      * Operation may be started by virtually any Widget.
      * <p>
@@ -251,6 +257,7 @@ public class VDragAndDropManager {
     public VDragEvent startDrag(VTransferable transferable,
             final NativeEvent startEvent, final boolean handleDragEvents) {
         interruptDrag();
+        isStarted = false;
 
         currentDrag = new VDragEvent(transferable, startEvent);
         updateCurrentEvent(startEvent);
@@ -258,6 +265,7 @@ public class VDragAndDropManager {
         final Command startDrag = new Command() {
 
             public void execute() {
+                isStarted = true;
                 VDropHandler dh = null;
                 if (startEvent != null) {
                     dh = findDragTarget((Element) currentDrag.currentGwtEvent
@@ -273,84 +281,86 @@ public class VDragAndDropManager {
                 if (handleDragEvents) {
                     handlerRegistration = Event
                             .addNativePreviewHandler(defaultDragAndDropEventHandler);
+                    if (dragElement != null
+                            && dragElement.getParentElement() == null) {
+                        // deferred attaching drag image is on going, we can
+                        // hurry with it now
+                        lazyAttachDragElement.cancel();
+                        lazyAttachDragElement.run();
+                    }
                 }
             }
         };
 
-        if (handleDragEvents) {
+        if (handleDragEvents
+                && Event.as(startEvent).getTypeInt() == Event.ONMOUSEDOWN) {
             // only really start drag event on mousemove
-            if (Event.as(startEvent).getTypeInt() == Event.ONMOUSEDOWN) {
-
-                deferredStartRegistration = Event
-                        .addNativePreviewHandler(new NativePreviewHandler() {
-
-                            public void onPreviewNativeEvent(
-                                    NativePreviewEvent event) {
-                                int typeInt = event.getTypeInt();
-                                switch (typeInt) {
-                                case Event.ONMOUSEOVER:
-                                    if (dragElement == null
-                                            || !dragElement
-                                                    .isOrHasChild((Node) event
-                                                            .getNativeEvent()
-                                                            .getCurrentEventTarget()
-                                                            .cast())) {
-                                        // drag image appeared below, ignore
-                                        ApplicationConnection.getConsole().log(
-                                                "Drag image appeared");
-                                        break;
-                                    }
-                                case Event.ONKEYDOWN:
-                                case Event.ONKEYPRESS:
-                                case Event.ONKEYUP:
-                                case Event.ONBLUR:
-                                    // don't cancel possible drag start
-                                    break;
-                                case Event.ONMOUSEOUT:
-
-                                    if (dragElement == null
-                                            || !dragElement
-                                                    .isOrHasChild((Node) event
-                                                            .getNativeEvent()
-                                                            .getRelatedEventTarget()
-                                                            .cast())) {
-                                        // drag image appeared below, ignore
-                                        ApplicationConnection.getConsole().log(
-                                                "Drag image appeared");
-                                        break;
-                                    }
-                                case Event.ONMOUSEMOVE:
-                                    deferredStartRegistration.removeHandler();
-                                    deferredStartRegistration = null;
-                                    updateCurrentEvent(event.getNativeEvent());
-                                    startDrag.execute();
+            deferredStartRegistration = Event
+                    .addNativePreviewHandler(new NativePreviewHandler() {
+
+                        public void onPreviewNativeEvent(
+                                NativePreviewEvent event) {
+                            int typeInt = event.getTypeInt();
+                            switch (typeInt) {
+                            case Event.ONMOUSEOVER:
+                                if (dragElement == null
+                                        || !dragElement
+                                                .isOrHasChild((Node) event
+                                                        .getNativeEvent()
+                                                        .getCurrentEventTarget()
+                                                        .cast())) {
+                                    // drag image appeared below, ignore
+                                    ApplicationConnection.getConsole().log(
+                                            "Drag image appeared");
                                     break;
-                                default:
-                                    // on any other events, clean up the
-                                    // deferred drag start
+                                }
+                            case Event.ONKEYDOWN:
+                            case Event.ONKEYPRESS:
+                            case Event.ONKEYUP:
+                            case Event.ONBLUR:
+                                // don't cancel possible drag start
+                                break;
+                            case Event.ONMOUSEOUT:
+
+                                if (dragElement == null
+                                        || !dragElement
+                                                .isOrHasChild((Node) event
+                                                        .getNativeEvent()
+                                                        .getRelatedEventTarget()
+                                                        .cast())) {
+                                    // drag image appeared below, ignore
                                     ApplicationConnection.getConsole().log(
-                                            "Drag did not start due event"
-                                                    + event.getNativeEvent()
-                                                            .getType());
-
-                                    deferredStartRegistration.removeHandler();
-                                    deferredStartRegistration = null;
-                                    currentDrag = null;
-                                    if (dragElement != null) {
-                                        RootPanel.getBodyElement().removeChild(
-                                                dragElement);
-                                        dragElement = null;
-                                    }
+                                            "Drag image appeared");
                                     break;
                                 }
-
+                            case Event.ONMOUSEMOVE:
+                                deferredStartRegistration.removeHandler();
+                                deferredStartRegistration = null;
+                                updateCurrentEvent(event.getNativeEvent());
+                                startDrag.execute();
+                                break;
+                            default:
+                                // on any other events, clean up the
+                                // deferred drag start
+                                ApplicationConnection.getConsole().log(
+                                        "Drag did not start due event"
+                                                + event.getNativeEvent()
+                                                        .getType());
+
+                                deferredStartRegistration.removeHandler();
+                                deferredStartRegistration = null;
+                                currentDrag = null;
+                                if (dragElement != null) {
+                                    RootPanel.getBodyElement().removeChild(
+                                            dragElement);
+                                    dragElement = null;
+                                }
+                                break;
                             }
 
-                        });
+                        }
 
-            } else {
-                startDrag.execute();
-            }
+                    });
 
         } else {
             startDrag.execute();
@@ -454,7 +464,9 @@ public class VDragAndDropManager {
         currentDrag = null;
 
         if (dragElement != null) {
-            RootPanel.getBodyElement().removeChild(dragElement);
+            if (dragElement.getParentElement() != null) {
+                RootPanel.getBodyElement().removeChild(dragElement);
+            }
             dragElement = null;
         }
     }
@@ -472,8 +484,8 @@ public class VDragAndDropManager {
      * 
      * @param acceptCallback
      */
-    public void visitServer(DragEventType type, VAcceptCallback acceptCallback) {
-        doRequest(type);
+    public void visitServer(VAcceptCallback acceptCallback) {
+        doRequest(DragEventType.ENTER);
         this.acceptCallback = acceptCallback;
     }
 
@@ -499,15 +511,6 @@ public class VDragAndDropManager {
 
         VTransferable transferable = currentDrag.getTransferable();
 
-        if (transferable.getItemId() != null) {
-            client.updateVariable(DD_SERVICE, "itemId", transferable
-                    .getItemId(), false);
-        }
-        if (transferable.getPropertyId() != null) {
-            client.updateVariable(DD_SERVICE, "propertyId", transferable
-                    .getPropertyId(), false);
-        }
-
         client.updateVariable(DD_SERVICE, "component", transferable
                 .getComponent(), false);
 
@@ -541,7 +544,9 @@ public class VDragAndDropManager {
         }
         int visitId = valueMap.getInt("visitId");
         if (this.visitId == visitId) {
-            acceptCallback.handleResponse(valueMap);
+            if (valueMap.containsKey("accepted")) {
+                acceptCallback.accepted();
+            }
             acceptCallback = null;
         }
     }
@@ -560,13 +565,18 @@ public class VDragAndDropManager {
             style.setZIndex(600000);
             updateDragImagePosition();
 
-            /*
-             * To make our default dnd handler as compatible as possible, we
-             * need to defer the appearance of dragElement. Otherwise events
-             * that are derived from sequences of other events might not fire as
-             * domchanged will fire between them.
-             */
-            lazyAttachDragElement.schedule(300);
+            if (isStarted) {
+                lazyAttachDragElement.run();
+            } else {
+                /*
+                 * To make our default dnd handler as compatible as possible, we
+                 * need to defer the appearance of dragElement. Otherwise events
+                 * that are derived from sequences of other events might not
+                 * fire as domchanged will fire between them or mouse up might
+                 * happen on dragElement.
+                 */
+                lazyAttachDragElement.schedule(300);
+            }
         }
     }
 
@@ -574,7 +584,7 @@ public class VDragAndDropManager {
 
         @Override
         public void run() {
-            if (dragElement != null) {
+            if (dragElement != null && dragElement.getParentElement() == null) {
                 RootPanel.getBodyElement().appendChild(dragElement);
             }
 
diff --git a/src/com/vaadin/terminal/gwt/client/ui/dd/VDragEvent.java b/src/com/vaadin/terminal/gwt/client/ui/dd/VDragEvent.java
index a35a4a7e0c..d75e4e0355 100644
--- a/src/com/vaadin/terminal/gwt/client/ui/dd/VDragEvent.java
+++ b/src/com/vaadin/terminal/gwt/client/ui/dd/VDragEvent.java
@@ -9,6 +9,7 @@ import com.google.gwt.dom.client.NativeEvent;
 import com.google.gwt.dom.client.TableElement;
 import com.google.gwt.dom.client.TableSectionElement;
 import com.google.gwt.dom.client.Style.Unit;
+import com.google.gwt.event.dom.client.MouseOverEvent;
 import com.google.gwt.user.client.Element;
 import com.vaadin.terminal.gwt.client.BrowserInfo;
 
@@ -49,14 +50,26 @@ public class VDragEvent {
         return transferable;
     }
 
+    /**
+     * Returns the the latest {@link NativeEvent} that relates to this drag and
+     * drop operation. For example on {@link VDropHandler#dragEnter(VDragEvent)}
+     * this is commonly a {@link MouseOverEvent}.
+     * 
+     * @return
+     */
     public NativeEvent getCurrentGwtEvent() {
         return currentGwtEvent;
     }
 
-    public int getEventId() {
+    int getEventId() {
         return id;
     }
 
+    /**
+     * @deprecated will be removed from final implementation, here just to aid
+     *             development.
+     */
+    @Deprecated
     public long sinceStart() {
         return new Date().getTime() - start.getTime();
     }
@@ -64,11 +77,11 @@ public class VDragEvent {
     /**
      * Detecting the element on which the the event is happening may be
      * problematic during drag and drop operation. This is especially the case
-     * if a drag image (often called drag proxy) is kept under the mouse cursor
-     * (see {@link #createDragImage(Element, boolean)}. Drag and drop event
-     * handlers (like the one provided by {@link VDragAndDropManager} ) should
-     * set elmentOver field to reflect the the actual element on which the
-     * pointer currently is (drag image excluded). {@link VDropHandler}s can
+     * if a drag image (often called also drag proxy) is kept under the mouse
+     * cursor (see {@link #createDragImage(Element, boolean)}. Drag and drop
+     * event handlers (like the one provided by {@link VDragAndDropManager} )
+     * should set elmentOver field to reflect the the actual element on which
+     * the pointer currently is (drag image excluded). {@link VDropHandler}s can
      * then more easily react properly on drag events by reading the element via
      * this method.
      * 
@@ -93,8 +106,8 @@ public class VDragEvent {
      * TODO decide if this method should be here or in {@link VTransferable} (in
      * HTML5 it is in DataTransfer) or {@link VDragAndDropManager}
      * 
-     * TODO should be possible to override behaviour an set to HTML5
-     * DataTransfer
+     * TODO should be possible to override behavior. Like to proxy the element
+     * to HTML5 DataTransfer
      * 
      * @param node
      */
diff --git a/src/com/vaadin/terminal/gwt/client/ui/dd/VHtml5DragEvent.java b/src/com/vaadin/terminal/gwt/client/ui/dd/VHtml5DragEvent.java
index 6689fbe307..3aaff0b5e0 100644
--- a/src/com/vaadin/terminal/gwt/client/ui/dd/VHtml5DragEvent.java
+++ b/src/com/vaadin/terminal/gwt/client/ui/dd/VHtml5DragEvent.java
@@ -3,6 +3,10 @@ package com.vaadin.terminal.gwt.client.ui.dd;
 import com.google.gwt.core.client.JsArrayString;
 import com.google.gwt.dom.client.NativeEvent;
 
+/**
+ * Helper class to access html5 style drag events.
+ * 
+ */
 public class VHtml5DragEvent extends NativeEvent {
     protected VHtml5DragEvent() {
     }
diff --git a/src/com/vaadin/terminal/gwt/client/ui/dd/VTransferable.java b/src/com/vaadin/terminal/gwt/client/ui/dd/VTransferable.java
index f04a4d8e33..2654f9a013 100644
--- a/src/com/vaadin/terminal/gwt/client/ui/dd/VTransferable.java
+++ b/src/com/vaadin/terminal/gwt/client/ui/dd/VTransferable.java
@@ -18,6 +18,9 @@ public class VTransferable {
     private final Map<String, Object> variables = new HashMap<String, Object>();
 
     /**
+     * Returns the component currently being dragged or from which the
+     * transferable is created (eg. a tree which node is dragged).
+     * 
      * @return the component
      */
     public Paintable getComponent() {
@@ -25,6 +28,13 @@ public class VTransferable {
     }
 
     /**
+     * Sets the component currently being dragged or from which the transferable
+     * is created (eg. a tree which node is dragged).
+     * <p>
+     * The server side counterpart of the componennt may implement
+     * {@link DragSource} interface if it wants to translate or complement the
+     * server side instance of this Transferable.
+     * 
      * @param component
      *            the component to set
      */
@@ -32,51 +42,6 @@ public class VTransferable {
         this.component = component;
     }
 
-    /**
-     * This is commonly actually a key to property id on client side than the
-     * actual propertyId.
-     * 
-     * Translated by terminal and {@link DragSource}
-     * 
-     * @return the propertyId
-     */
-    public String getPropertyId() {
-        return (String) variables.get("propertyId");
-    }
-
-    /**
-     * This is commonly actually a key to property id on client side than the
-     * actual propertyId.
-     * 
-     * Translated by terminal and {@link DragSource}
-     * 
-     * @param propertyId
-     *            the propertyId to set
-     */
-    public void setPropertyId(String propertyId) {
-        variables.put("propertyId", propertyId);
-    }
-
-    /**
-     * @return the itemId
-     */
-    public String getItemId() {
-        return (String) variables.get("itemId");
-    }
-
-    /**
-     * This is commonly actually a key to item id on client side than the actual
-     * itemId.
-     * 
-     * Translated by terminal and {@link DragSource}
-     * 
-     * @param itemId
-     *            the itemId to set
-     */
-    public void setItemId(String itemId) {
-        variables.put("itemId", itemId);
-    }
-
     public Object getData(String dataFlawor) {
         return variables.get(dataFlawor);
     }
@@ -90,11 +55,11 @@ public class VTransferable {
     }
 
     /**
-     * This method should only be called by {@link VDragAndDropManager}.
+     * This helper method should only be called by {@link VDragAndDropManager}.
      * 
      * @return data in this Transferable that needs to be moved to server.
      */
-    public Map<String, Object> getVariableMap() {
+    Map<String, Object> getVariableMap() {
         return variables;
     }