HTML5 Drag and Drop Support (#8264)

* Add DragSource Extension (#8169)

* Add DropTarget Extension (#8170)

* Add DragStart Event to DragSource Extension (#8171)

* Make DataTransfer.dropEffect configurable (#8174)

* Make DragSource.dataTransfer data configurable (#8172)

* Add server-side Event for drop (#8177)

* Added license headers

* Extract handler methods, move DropEvent and DropListener to new file, move enums to top

* Replaced LinkedHashMap with Map and added List to preserve order of data

* Add API for adding a JS acceptance criteria for dragover and drop (#8178, #8179)

* Make DragSource Extension extendable (#8175)

* Make DropTarget Extension extendable (#8176)

* Added javadoc to protected methods

* Moved EffectAllowed to shared so that it could be used in shared state directly

* Moved DropEffect to separate file, some review fixes and javadoc

* Added list to DropTargetRpc to preserve order of data

* Remove event listeners on unregister

* Changed method names set/getData() to more descriptive set/getTransferData()

* Add server side dragStart event (#8171)

* Add style to prevent text selection to allow drag

* Remove target indicator style on drop

* Add client side dragend event listener for drag source

* Add server side dragend listener.
Attach client side listener only when server side listener added.

* Add drag source information to server side dragstart and dragend events.

* Fixed some issues addressed in review

* Trigger server side dragstart only when there is a listener attached

* Criteria script can be set as null to clear

* Use Js Interop instead of JSNI for handling event listeners

* Use elemental package instead of Js Interop for handling event listeners

* Add missing javadoc for public methods

* Add default value "uninitialized" to effectAllowed parameter

* Simple test UI for HTML5 DnD functionality (#8395)

* Add javadoc and other minor changes

19 files changed, 1535 insertions, 0 deletions

diff --git a/client/src/main/java/com/vaadin/client/extensions/DragSourceExtensionConnector.java b/client/src/main/java/com/vaadin/client/extensions/DragSourceExtensionConnector.java
new file mode 100644
index 0000000000..25e2912b7a
--- /dev/null
+++ b/client/src/main/java/com/vaadin/client/extensions/DragSourceExtensionConnector.java
@@ -0,0 +1,139 @@
+/*
+ * Copyright 2000-2016 Vaadin Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package com.vaadin.client.extensions;
+
+import java.util.List;
+import java.util.Map;
+
+import com.google.gwt.dom.client.DataTransfer;
+import com.google.gwt.dom.client.Element;
+import com.google.gwt.dom.client.NativeEvent;
+import com.vaadin.client.ComponentConnector;
+import com.vaadin.client.ServerConnector;
+import com.vaadin.event.dnd.DragSourceExtension;
+import com.vaadin.shared.ui.Connect;
+import com.vaadin.shared.ui.dnd.DragSourceRpc;
+import com.vaadin.shared.ui.dnd.DragSourceState;
+
+import elemental.events.Event;
+import elemental.events.EventListener;
+import elemental.events.EventTarget;
+
+/**
+ * Extension to add drag source functionality to a widget for using HTML5 drag
+ * and drop. Client side counterpart of {@link DragSourceExtension}.
+ */
+@Connect(DragSourceExtension.class)
+public class DragSourceExtensionConnector extends AbstractExtensionConnector {
+
+    private static final String CLASS_DRAGGABLE = "v-draggable";
+
+    // Create event listeners
+    private final EventListener dragStartListener = this::onDragStart;
+    private final EventListener dragEndListener = this::onDragEnd;
+
+    @Override
+    protected void extend(ServerConnector target) {
+        Element dragSourceElement = getDraggableElement();
+
+        dragSourceElement.setDraggable(Element.DRAGGABLE_TRUE);
+        dragSourceElement.addClassName(CLASS_DRAGGABLE);
+
+        EventTarget dragSource = dragSourceElement.cast();
+
+        // dragstart
+        dragSource.addEventListener(Event.DRAGSTART, dragStartListener);
+
+        // dragend
+        dragSource.addEventListener(Event.DRAGEND, dragEndListener);
+    }
+
+    @Override
+    public void onUnregister() {
+        super.onUnregister();
+
+        EventTarget dragSource = (EventTarget) getDraggableElement();
+
+        // Remove listeners
+        dragSource.removeEventListener(Event.DRAGSTART, dragStartListener);
+        dragSource.removeEventListener(Event.DRAGEND, dragEndListener);
+    }
+
+    /**
+     * Event handler for the {@code dragstart} event. Called when {@code
+     * dragstart} event occurs.
+     *
+     * @param event
+     *         browser event to be handled
+     */
+    protected void onDragStart(Event event) {
+        // Convert elemental event to have access to dataTransfer
+        NativeEvent nativeEvent = (NativeEvent) event;
+
+        // Set effectAllowed parameter
+        if (getState().effectAllowed != null) {
+            setEffectAllowed(nativeEvent.getDataTransfer(),
+                    getState().effectAllowed.getValue());
+        }
+
+        // Set data parameter
+        List<String> types = getState().types;
+        Map<String, String> data = getState().data;
+        for (String format : types) {
+            nativeEvent.getDataTransfer().setData(format, data.get(format));
+        }
+
+        // Initiate firing server side dragstart event when there is a
+        // DragStartListener attached on the server side
+        if (hasEventListener(DragSourceState.EVENT_DRAGSTART)) {
+            getRpcProxy(DragSourceRpc.class).dragStart();
+        }
+    }
+
+    /**
+     * Event handler for the {@code dragend} event. Called when {@code dragend}
+     * event occurs.
+     *
+     * @param event
+     */
+    protected void onDragEnd(Event event) {
+        // Initiate server start dragend event when there is a DragEndListener
+        // attached on the server side
+        if (hasEventListener(DragSourceState.EVENT_DRAGEND)) {
+            getRpcProxy(DragSourceRpc.class).dragEnd();
+        }
+    }
+
+    /**
+     * Finds the draggable element within the widget. By default, returns the
+     * topmost element.
+     *
+     * @return the draggable element in the parent widget.
+     */
+    protected Element getDraggableElement() {
+        return ((ComponentConnector) getParent()).getWidget().getElement();
+    }
+
+    private native void setEffectAllowed(DataTransfer dataTransfer,
+            String effectAllowed)/*-{
+        dataTransfer.effectAllowed = effectAllowed;
+    }-*/;
+
+    @Override
+    public DragSourceState getState() {
+        return (DragSourceState) super.getState();
+    }
+}
diff --git a/client/src/main/java/com/vaadin/client/extensions/DropTargetExtensionConnector.java b/client/src/main/java/com/vaadin/client/extensions/DropTargetExtensionConnector.java
new file mode 100644
index 0000000000..5d72a76696
--- /dev/null
+++ b/client/src/main/java/com/vaadin/client/extensions/DropTargetExtensionConnector.java
@@ -0,0 +1,223 @@
+/*
+ * Copyright 2000-2016 Vaadin Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package com.vaadin.client.extensions;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import com.google.gwt.core.client.JsArrayString;
+import com.google.gwt.dom.client.BrowserEvents;
+import com.google.gwt.dom.client.DataTransfer;
+import com.google.gwt.dom.client.Element;
+import com.google.gwt.dom.client.NativeEvent;
+import com.vaadin.client.ComponentConnector;
+import com.vaadin.client.ServerConnector;
+import com.vaadin.event.dnd.DropTargetExtension;
+import com.vaadin.shared.ui.Connect;
+import com.vaadin.shared.ui.dnd.DropTargetRpc;
+import com.vaadin.shared.ui.dnd.DropTargetState;
+
+import elemental.events.Event;
+import elemental.events.EventListener;
+import elemental.events.EventTarget;
+
+/**
+ * Extension to add drop target functionality to a widget for using HTML5 drag
+ * and drop. Client side counterpart of {@link DropTargetExtension}.
+ */
+@Connect(DropTargetExtension.class)
+public class DropTargetExtensionConnector extends AbstractExtensionConnector {
+
+    private static final String CLASS_DRAG_OVER = "v-drag-over";
+
+    // Create event listeners
+    private final EventListener dragEnterListener = this::onDragEnter;
+    private final EventListener dragOverListener = this::onDragOver;
+    private final EventListener dragLeaveListener = this::onDragLeave;
+    private final EventListener dropListener = this::onDrop;
+
+    @Override
+    protected void extend(ServerConnector target) {
+        EventTarget dropTarget = getDropTargetElement().cast();
+
+        // dragenter event
+        dropTarget.addEventListener(BrowserEvents.DRAGENTER, dragEnterListener);
+
+        // dragover event
+        dropTarget.addEventListener(BrowserEvents.DRAGOVER, dragOverListener);
+
+        // dragleave event
+        dropTarget.addEventListener(BrowserEvents.DRAGLEAVE, dragLeaveListener);
+
+        // drop event
+        dropTarget.addEventListener(BrowserEvents.DROP, dropListener);
+    }
+
+    @Override
+    public void onUnregister() {
+        super.onUnregister();
+
+        EventTarget dropTarget = getDropTargetElement().cast();
+
+        // Remove listeners
+        dropTarget.removeEventListener(BrowserEvents.DRAGENTER,
+                dragEnterListener);
+        dropTarget.removeEventListener(BrowserEvents.DRAGOVER,
+                dragOverListener);
+        dropTarget.removeEventListener(BrowserEvents.DRAGLEAVE,
+                dragLeaveListener);
+        dropTarget.removeEventListener(BrowserEvents.DROP, dropListener);
+    }
+
+    /**
+     * Finds the drop target element within the widget. By default, returns the
+     * topmost element.
+     *
+     * @return the drop target element in the parent widget.
+     */
+    protected Element getDropTargetElement() {
+        return ((ComponentConnector) getParent()).getWidget().getElement();
+    }
+
+    /**
+     * Event handler for the {@code dragenter} event.
+     *
+     * @param event
+     *         browser event to be handled
+     */
+    protected void onDragEnter(Event event) {
+        addTargetIndicator(getDropTargetElement());
+    }
+
+    /**
+     * Event handler for the {@code dragover} event.
+     *
+     * @param event
+     *         browser event to be handled
+     */
+    protected void onDragOver(Event event) {
+        NativeEvent nativeEvent = (NativeEvent) event;
+        if (isDragOverAllowed(nativeEvent)) {
+            // Set dropEffect parameter
+            if (getState().dropEffect != null) {
+                nativeEvent.getDataTransfer().setDropEffect(
+                        DataTransfer.DropEffect
+                                .valueOf(getState().dropEffect.name()));
+            }
+
+            // Prevent default to allow drop
+            nativeEvent.preventDefault();
+            nativeEvent.stopPropagation();
+        } else {
+            // Remove drop effect
+            nativeEvent.getDataTransfer()
+                    .setDropEffect(DataTransfer.DropEffect.NONE);
+
+            // Remove drop target indicator
+            removeTargetIndicator(getDropTargetElement());
+        }
+    }
+
+    /**
+     * Determines if dragover event is allowed on this drop target according to
+     * the dragover criteria.
+     *
+     * @param event
+     *         Native dragover event.
+     * @return {@code true} if dragover is allowed, {@code false} otherwise.
+     * @see DropTargetExtension#setDragOverCriteria(String)
+     */
+    protected boolean isDragOverAllowed(NativeEvent event) {
+        if (getState().dragOverCriteria != null) {
+            return executeScript(event, getState().dragOverCriteria);
+        }
+
+        // Allow when criteria not set
+        return true;
+    }
+
+    /**
+     * Event handler for the {@code dragleave} event.
+     *
+     * @param event
+     *         browser event to be handled
+     */
+    protected void onDragLeave(Event event) {
+        removeTargetIndicator(getDropTargetElement());
+    }
+
+    /**
+     * Event handler for the {@code drop} event.
+     *
+     * @param event
+     *         browser event to be handled
+     */
+    protected void onDrop(Event event) {
+        NativeEvent nativeEvent = (NativeEvent) event;
+        if (dropAllowed(nativeEvent)) {
+            nativeEvent.preventDefault();
+            nativeEvent.stopPropagation();
+
+            // Initiate firing server side drop event
+            JsArrayString typesJsArray = getTypes(
+                    nativeEvent.getDataTransfer());
+            List<String> types = new ArrayList<>();
+            Map<String, String> data = new HashMap<>();
+            for (int i = 0; i < typesJsArray.length(); i++) {
+                types.add(typesJsArray.get(i));
+                data.put(typesJsArray.get(i), nativeEvent.getDataTransfer()
+                        .getData(typesJsArray.get(i)));
+            }
+
+            getRpcProxy(DropTargetRpc.class)
+                    .drop(types, data, getState().dropEffect);
+        }
+
+        removeTargetIndicator(getDropTargetElement());
+    }
+
+    private boolean dropAllowed(NativeEvent event) {
+        if (getState().dropCriteria != null) {
+            return executeScript(event, getState().dropCriteria);
+        }
+
+        // Allow when criteria not set
+        return true;
+    }
+
+    private void addTargetIndicator(Element element) {
+        element.addClassName(CLASS_DRAG_OVER);
+    }
+
+    private void removeTargetIndicator(Element element) {
+        element.removeClassName(CLASS_DRAG_OVER);
+    }
+
+    private native boolean executeScript(NativeEvent event, String script)/*-{
+        return new Function('event', script)(event);
+    }-*/;
+
+    private native JsArrayString getTypes(DataTransfer dataTransfer)/*-{
+        return dataTransfer.types;
+    }-*/;
+
+    @Override
+    public DropTargetState getState() {
+        return (DropTargetState) super.getState();
+    }
+}
diff --git a/server/src/main/java/com/vaadin/event/dnd/DragEndEvent.java b/server/src/main/java/com/vaadin/event/dnd/DragEndEvent.java
new file mode 100644
index 0000000000..6f094ce9e2
--- /dev/null
+++ b/server/src/main/java/com/vaadin/event/dnd/DragEndEvent.java
@@ -0,0 +1,77 @@
+/*
+ * Copyright 2000-2016 Vaadin Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package com.vaadin.event.dnd;
+
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+
+import com.vaadin.shared.ui.dnd.EffectAllowed;
+import com.vaadin.ui.Component;
+
+/**
+ * Server side dragend event. Fired when an HTML5 dragend happens.
+ *
+ * @see DragSourceExtension#addDragEndListener(DragEndListener)
+ */
+public class DragEndEvent extends Component.Event {
+    private final Map<String, String> data;
+    private final EffectAllowed effectAllowed;
+
+    /**
+     * Creates a new server side dragend event.
+     *
+     * @param source
+     *         Draggable component.
+     * @param types
+     *         List of data types from {@code DataTransfer.types}.
+     * @param data
+     *         Map of all data from {@code DataTransfer}.
+     * @param effectAllowed
+     *         Parameter from {@code DataTransfer.effectAllowed}.
+     */
+    public DragEndEvent(Component source, List<String> types,
+            Map<String, String> data, EffectAllowed effectAllowed) {
+        super(source);
+
+        // Create a linked map that preserves the order of types
+        this.data = new LinkedHashMap<>();
+        types.forEach(type -> this.data.put(type, data.get(type)));
+
+        this.effectAllowed = effectAllowed;
+    }
+
+    /**
+     * Get data from the client side {@code DataTransfer} object.
+     *
+     * @param format
+     *         Data format, e.g. {@code text/plain} or {@code text/uri-list}.
+     * @return Data for the given format if exists in the client side {@code
+     * DataTransfer}, otherwise {@code null}.
+     */
+    public String getTransferData(String format) {
+        return data != null ? data.get(format) : null;
+    }
+
+    /**
+     * Returns the {@code effectAllowed} parameter of this event.
+     *
+     * @return This event's {@code effectAllowed} parameter.
+     */
+    public EffectAllowed getEffectAllowed() {
+        return effectAllowed;
+    }
+}
diff --git a/server/src/main/java/com/vaadin/event/dnd/DragEndListener.java b/server/src/main/java/com/vaadin/event/dnd/DragEndListener.java
new file mode 100644
index 0000000000..00a020353d
--- /dev/null
+++ b/server/src/main/java/com/vaadin/event/dnd/DragEndListener.java
@@ -0,0 +1,40 @@
+/*
+ * Copyright 2000-2016 Vaadin Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package com.vaadin.event.dnd;
+
+import java.lang.reflect.Method;
+
+import com.vaadin.event.ConnectorEventListener;
+
+/**
+ * Interface to be implemented when creating a dragend listener on a drag
+ * source for HTML5 drag and drop.
+ *
+ * @see DragSourceExtension#addDragEndListener(DragEndListener)
+ */
+@FunctionalInterface
+public interface DragEndListener extends ConnectorEventListener {
+    static final Method DRAGEND_METHOD = DragEndListener.class
+            .getDeclaredMethods()[0];
+
+    /**
+     * Called when a server side dragend event is fired.
+     *
+     * @param event
+     *         The dragend event that is fired.
+     */
+    void dragEnd(DragEndEvent event);
+}
diff --git a/server/src/main/java/com/vaadin/event/dnd/DragSourceExtension.java b/server/src/main/java/com/vaadin/event/dnd/DragSourceExtension.java
new file mode 100644
index 0000000000..d90e1bd8b8
--- /dev/null
+++ b/server/src/main/java/com/vaadin/event/dnd/DragSourceExtension.java
@@ -0,0 +1,226 @@
+/*
+ * Copyright 2000-2016 Vaadin Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package com.vaadin.event.dnd;
+
+import java.util.Collections;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.Objects;
+
+import com.vaadin.server.AbstractClientConnector;
+import com.vaadin.server.AbstractExtension;
+import com.vaadin.shared.Registration;
+import com.vaadin.shared.ui.dnd.DragSourceRpc;
+import com.vaadin.shared.ui.dnd.DragSourceState;
+import com.vaadin.shared.ui.dnd.EffectAllowed;
+import com.vaadin.ui.AbstractComponent;
+
+/**
+ * Extension to add drag source functionality to a component for using HTML5
+ * drag and drop.
+ */
+public class DragSourceExtension extends AbstractExtension {
+
+    /**
+     * Constructor for {@link DragSourceExtension}
+     */
+    public DragSourceExtension() {
+        registerRpc(new DragSourceRpc() {
+            @Override
+            public void dragStart() {
+                DragStartEvent event = new DragStartEvent(
+                        (AbstractComponent) getParent(), getState(false).types,
+                        getState(false).data, getState(false).effectAllowed);
+                fireEvent(event);
+            }
+
+            @Override
+            public void dragEnd() {
+                DragEndEvent event = new DragEndEvent(
+                        (AbstractComponent) getParent(), getState(false).types,
+                        getState(false).data, getState(false).effectAllowed);
+                fireEvent(event);
+            }
+        });
+    }
+
+    /**
+     * Makes {@code target} component a drag source.
+     *
+     * @param target
+     *         Component to be extended.
+     */
+    public void extend(AbstractComponent target) {
+        super.extend(target);
+    }
+
+    /**
+     * Sets the allowed effects for the current drag source element. Used for
+     * setting client side {@code DataTransfer.effectAllowed} parameter for the
+     * drag event.
+     * <p>
+     * By default the value is {@link EffectAllowed#UNINITIALIZED} which is
+     * equivalent to {@link EffectAllowed#ALL}.
+     *
+     * @param effect
+     *         Effects to allow for this draggable element. Cannot be {@code
+     *         null}.
+     */
+    public void setEffectAllowed(EffectAllowed effect) {
+        if (effect == null) {
+            throw new IllegalArgumentException("Allowed effect cannot be null");
+        }
+        if (!Objects.equals(getState(false).effectAllowed, effect)) {
+            getState().effectAllowed = effect;
+        }
+    }
+
+    /**
+     * Returns the allowed effects for the current drag source element. Used to
+     * set client side {@code DataTransfer.effectAllowed} parameter for the drag
+     * event.
+     *
+     * @return Effects that are allowed for this draggable element.
+     */
+    public EffectAllowed getEffectAllowed() {
+        return getState(false).effectAllowed;
+    }
+
+    /**
+     * Sets the data for this drag source element. Used to set data for client
+     * side drag element using {@code DataTransfer.setData()}. To be used as a
+     * map, key-value pairs are stored. Order of entries are preserved.
+     * <p>
+     * Note that by HTML specification, the browser will change data type
+     * "{@code text}" to "{@code text/plain}" and "{@code url}" to "{@code
+     * text/uri-list}" during client side drag event.
+     *
+     * @param format
+     *         Data type to store, e.g. {@code text/plain} or {@code
+     *         text/uri-list}. Cannot be {@code null}.
+     * @param data
+     *         Data to store for the data type. Cannot be {@code null}.
+     */
+    public void setTransferData(String format, String data) {
+        if (format == null) {
+            throw new IllegalArgumentException("Data type cannot be null");
+        }
+
+        if (data == null) {
+            throw new IllegalArgumentException("Data cannot be null");
+        }
+
+        if (!getState(false).types.contains(format)) {
+            getState().types.add(format);
+        }
+        getState().data.put(format, data);
+    }
+
+    /**
+     * Returns the data stored for {@code format} type in this drag source
+     * element.
+     *
+     * @param format
+     *         Data type of the requested data, e.g. {@code text/plain} or
+     *         {@code text/uri-list}.
+     * @return Data that is stored for {@code format} data type.
+     */
+    public String getTransferData(String format) {
+        return getState(false).data.get(format);
+    }
+
+    /**
+     * Returns the map of data stored in this drag source element. The returned
+     * map preserves the order of storage and is unmodifiable.
+     *
+     * @return Unmodifiable copy of the map of data in the order the data was
+     * stored.
+     */
+    public Map<String, String> getTransferData() {
+        Map<String, String> data = getState(false).data;
+
+        // Create a map of data that preserves the order of types
+        LinkedHashMap<String, String> orderedData = new LinkedHashMap<>(
+                data.size());
+        getState(false).types
+                .forEach(type -> orderedData.put(type, data.get(type)));
+
+        return Collections.unmodifiableMap(orderedData);
+    }
+
+    /**
+     * Clears data with the given type for this drag source element when
+     * present.
+     *
+     * @param format
+     *         Type of data to be cleared. Cannot be {@code null}.
+     */
+    public void clearTransferData(String format) {
+        if (format == null) {
+            throw new IllegalArgumentException("Data type cannot be null");
+        }
+
+        getState().types.remove(format);
+        getState().data.remove(format);
+    }
+
+    /**
+     * Clears all data for this drag source element.
+     */
+    public void clearTransferData() {
+        getState().types.clear();
+        getState().data.clear();
+    }
+
+    /**
+     * Attaches dragstart listener for the current drag source. {@link
+     * DragStartListener#dragStart(DragStartEvent)} is called when dragstart
+     * event happens on the client side.
+     *
+     * @param listener
+     *         Listener to handle dragstart event.
+     * @return Handle to be used to remove this listener.
+     */
+    public Registration addDragStartListener(DragStartListener listener) {
+        return addListener(DragSourceState.EVENT_DRAGSTART,
+                DragStartEvent.class, listener,
+                DragStartListener.DRAGSTART_METHOD);
+    }
+
+    /**
+     * Attaches dragend listener for the current drag source. {@link
+     * DragEndListener#dragEnd(DragEndEvent)} is called when dragend
+     * event happens on the client side.
+     *
+     * @param listener
+     *         Listener to handle dragend event.
+     * @return Handle to be used to remove this listener.
+     */
+    public Registration addDragEndListener(DragEndListener listener) {
+        return addListener(DragSourceState.EVENT_DRAGEND, DragEndEvent.class,
+                listener, DragEndListener.DRAGEND_METHOD);
+    }
+
+    @Override
+    protected DragSourceState getState() {
+        return (DragSourceState) super.getState();
+    }
+
+    @Override
+    protected DragSourceState getState(boolean markAsDirty) {
+        return (DragSourceState) super.getState(markAsDirty);
+    }
+}
diff --git a/server/src/main/java/com/vaadin/event/dnd/DragStartEvent.java b/server/src/main/java/com/vaadin/event/dnd/DragStartEvent.java
new file mode 100644
index 0000000000..591a0e61a7
--- /dev/null
+++ b/server/src/main/java/com/vaadin/event/dnd/DragStartEvent.java
@@ -0,0 +1,77 @@
+/*
+ * Copyright 2000-2016 Vaadin Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package com.vaadin.event.dnd;
+
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+
+import com.vaadin.shared.ui.dnd.EffectAllowed;
+import com.vaadin.ui.Component;
+
+/**
+ * Server side dragstart event. Fired when an HTML5 dragstart happens.
+ *
+ * @see DragSourceExtension#addDragStartListener(DragStartListener)
+ */
+public class DragStartEvent extends Component.Event {
+    private final Map<String, String> data;
+    private final EffectAllowed effectAllowed;
+
+    /**
+     * Creates a new server side dragend event.
+     *
+     * @param source
+     *         Draggable component.
+     * @param types
+     *         List of data types from {@code DataTransfer.types}.
+     * @param data
+     *         Map of all data from {@code DataTransfer}.
+     * @param effectAllowed
+     *         Parameter from {@code DataTransfer.effectAllowed}.
+     */
+    public DragStartEvent(Component source, List<String> types,
+            Map<String, String> data, EffectAllowed effectAllowed) {
+        super(source);
+
+        // Create a linked map that preserves the order of types
+        this.data = new LinkedHashMap<>();
+        types.forEach(type -> this.data.put(type, data.get(type)));
+
+        this.effectAllowed = effectAllowed;
+    }
+
+    /**
+     * Get data from the client side {@code DataTransfer} object.
+     *
+     * @param format
+     *         Data format, e.g. {@code text/plain} or {@code text/uri-list}.
+     * @return Data for the given format if exists in the client side {@code
+     * DataTransfer}, otherwise {@code null}.
+     */
+    public String getTransferData(String format) {
+        return data != null ? data.get(format) : null;
+    }
+
+    /**
+     * Returns the {@code effectAllowed} parameter of this event.
+     *
+     * @return This event's {@code effectAllowed} parameter.
+     */
+    public EffectAllowed getEffectAllowed() {
+        return effectAllowed;
+    }
+}
diff --git a/server/src/main/java/com/vaadin/event/dnd/DragStartListener.java b/server/src/main/java/com/vaadin/event/dnd/DragStartListener.java
new file mode 100644
index 0000000000..8d691dee6b
--- /dev/null
+++ b/server/src/main/java/com/vaadin/event/dnd/DragStartListener.java
@@ -0,0 +1,40 @@
+/*
+ * Copyright 2000-2016 Vaadin Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package com.vaadin.event.dnd;
+
+import java.lang.reflect.Method;
+
+import com.vaadin.event.ConnectorEventListener;
+
+/**
+ * Interface to be implemented when creating a dragstart listener on a drag
+ * source for HTML5 drag and drop.
+ *
+ * @see DragSourceExtension#addDragStartListener(DragStartListener)
+ */
+@FunctionalInterface
+public interface DragStartListener extends ConnectorEventListener {
+    static final Method DRAGSTART_METHOD = DragStartListener.class
+            .getDeclaredMethods()[0];
+
+    /**
+     * Called when a server side dragstart event is fired.
+     *
+     * @param event
+     *         The dragstart event that is fired.
+     */
+    void dragStart(DragStartEvent event);
+}
diff --git a/server/src/main/java/com/vaadin/event/dnd/DropEvent.java b/server/src/main/java/com/vaadin/event/dnd/DropEvent.java
new file mode 100644
index 0000000000..382b93bc55
--- /dev/null
+++ b/server/src/main/java/com/vaadin/event/dnd/DropEvent.java
@@ -0,0 +1,77 @@
+/*
+ * Copyright 2000-2016 Vaadin Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package com.vaadin.event.dnd;
+
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+
+import com.vaadin.shared.ui.dnd.DropEffect;
+import com.vaadin.ui.Component;
+
+/**
+ * Server side drop event. Fired when an HTML5 drop happens.
+ *
+ * @see DropTargetExtension#addDropListener(DropListener)
+ */
+public class DropEvent extends Component.Event {
+    private final Map<String, String> data;
+    private final DropEffect dropEffect;
+
+    /**
+     * Creates a new server side drop event.
+     *
+     * @param source
+     *         Drop target component.
+     * @param types
+     *         List of data types from {@code DataTransfer.types}.
+     * @param data
+     *         Map of all data from {@code DataTransfer}.
+     * @param dropEffect
+     *         Parameter from {@code DataTransfer.dropEffect}.
+     */
+    public DropEvent(Component source, List<String> types,
+            Map<String, String> data, DropEffect dropEffect) {
+        super(source);
+
+        // Create a linked map that preserves the order of types
+        this.data = new LinkedHashMap<>();
+        types.forEach(type -> this.data.put(type, data.get(type)));
+
+        this.dropEffect = dropEffect;
+    }
+
+    /**
+     * Get data from the client side {@code DataTransfer} object.
+     *
+     * @param format
+     *         Data format, e.g. {@code text/plain} or {@code text/uri-list}.
+     * @return Data for the given format if exists in the client side {@code
+     * DataTransfer}, otherwise {@code null}.
+     */
+    public String getTransferData(String format) {
+        return data != null ? data.get(format) : null;
+    }
+
+    /**
+     * Get drop effect set for the current drop target.
+     *
+     * @return {@code dropEffect} parameter set for the current drop target.
+     */
+    public DropEffect getDropEffect() {
+        return dropEffect;
+    }
+}
diff --git a/server/src/main/java/com/vaadin/event/dnd/DropListener.java b/server/src/main/java/com/vaadin/event/dnd/DropListener.java
new file mode 100644
index 0000000000..8cb96d1852
--- /dev/null
+++ b/server/src/main/java/com/vaadin/event/dnd/DropListener.java
@@ -0,0 +1,38 @@
+/*
+ * Copyright 2000-2016 Vaadin Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package com.vaadin.event.dnd;
+
+import java.lang.reflect.Method;
+
+import com.vaadin.event.ConnectorEventListener;
+
+/**
+ * Interface to be implemented when creating a drop listener on a drop target
+ * for HTML5 drag and drop. See {@link DropTargetExtension#addDropListener(DropListener)}.
+ */
+@FunctionalInterface
+public interface DropListener extends ConnectorEventListener {
+    static final Method DROP_METHOD = DropListener.class
+            .getDeclaredMethods()[0];
+
+    /**
+     * Called when a server side drop event is fired.
+     *
+     * @param event
+     *         The drop event that is fired.
+     */
+    void drop(DropEvent event);
+}
diff --git a/server/src/main/java/com/vaadin/event/dnd/DropTargetExtension.java b/server/src/main/java/com/vaadin/event/dnd/DropTargetExtension.java
new file mode 100644
index 0000000000..20819ec70f
--- /dev/null
+++ b/server/src/main/java/com/vaadin/event/dnd/DropTargetExtension.java
@@ -0,0 +1,145 @@
+/*
+ * Copyright 2000-2016 Vaadin Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package com.vaadin.event.dnd;
+
+import java.util.Objects;
+
+import com.vaadin.server.AbstractClientConnector;
+import com.vaadin.server.AbstractExtension;
+import com.vaadin.shared.Registration;
+import com.vaadin.shared.ui.dnd.DropEffect;
+import com.vaadin.shared.ui.dnd.DropTargetRpc;
+import com.vaadin.shared.ui.dnd.DropTargetState;
+import com.vaadin.ui.AbstractComponent;
+
+/**
+ * Extension to add drop target functionality to a widget for using HTML5 drag
+ * and drop.
+ */
+public class DropTargetExtension extends AbstractExtension {
+
+    /**
+     * Constructor for {@link DropTargetExtension}.
+     */
+    public DropTargetExtension() {
+        registerRpc((DropTargetRpc) (types, data, dropEffect) -> {
+            DropEvent event = new DropEvent((AbstractComponent) getParent(),
+                    types, data, dropEffect);
+
+            fireEvent(event);
+        });
+    }
+
+    /**
+     * Makes {@code target} component a drop target.
+     *
+     * @param target
+     *         Component to be extended.
+     */
+    public void extend(AbstractComponent target) {
+        super.extend(target);
+    }
+
+    /**
+     * Sets the drop effect for the current drop target. Used for the client
+     * side {@code DataTransfer.dropEffect} parameter.
+     * <p>
+     * Default value is browser dependent and can depend on e.g. modifier keys.
+     *
+     * @param dropEffect
+     *         The drop effect to be set. Cannot be {@code null}.
+     */
+    public void setDropEffect(DropEffect dropEffect) {
+        if (dropEffect == null) {
+            throw new IllegalArgumentException("Drop effect cannot be null.");
+        }
+
+        if (!Objects.equals(getState(false).dropEffect, dropEffect)) {
+            getState().dropEffect = dropEffect;
+        }
+    }
+
+    /**
+     * Returns the drop effect for the current drop target.
+     *
+     * @return The drop effect of this drop target.
+     */
+    public DropEffect getDropEffect() {
+        return getState(false).dropEffect;
+    }
+
+    /**
+     * Sets criteria to allow dragover event on the current drop target. The
+     * script executes when dragover event happens and stops the event in case
+     * the script returns {@code false}.
+     *
+     * @param criteriaScript
+     *         JavaScript to be executed when dragover event happens or {@code
+     *         null} to clear.
+     */
+    public void setDragOverCriteria(String criteriaScript) {
+        if (!Objects.equals(getState(false).dragOverCriteria, criteriaScript)) {
+            getState().dragOverCriteria = criteriaScript;
+        }
+    }
+
+    /**
+     * Sets criteria to allow drop event on the current drop target. The script
+     * executes when drop event happens and stops the event in case the script
+     * returns {@code false}.
+     *
+     * @param criteriaScript
+     *         JavaScript to be executed when drop event happens or {@code null}
+     *         to clear.
+     */
+    public void setDropCriteria(String criteriaScript) {
+        if (!Objects.equals(getState(false).dropCriteria, criteriaScript)) {
+            getState().dropCriteria = criteriaScript;
+        }
+    }
+
+    /**
+     * Returns the criteria for allowing drop event on the current drop target.
+     *
+     * @return JavaScript that executes when drop event happens.
+     */
+    public String getDropCriteria() {
+        return getState(false).dropCriteria;
+    }
+
+    /**
+     * Attaches drop listener for the current drop target. {@link
+     * DropListener#drop(DropEvent)} is called when drop event happens on the
+     * client side.
+     *
+     * @param listener
+     *         Listener to handle drop event.
+     * @return Handle to be used to remove this listener.
+     */
+    public Registration addDropListener(DropListener listener) {
+        return addListener(DropEvent.class, listener, DropListener.DROP_METHOD);
+    }
+
+    @Override
+    protected DropTargetState getState() {
+        return (DropTargetState) super.getState();
+    }
+
+    @Override
+    protected DropTargetState getState(boolean markAsDirty) {
+        return (DropTargetState) super.getState(markAsDirty);
+    }
+}
diff --git a/shared/src/main/java/com/vaadin/shared/ui/dnd/DragSourceRpc.java b/shared/src/main/java/com/vaadin/shared/ui/dnd/DragSourceRpc.java
new file mode 100644
index 0000000000..bbad423044
--- /dev/null
+++ b/shared/src/main/java/com/vaadin/shared/ui/dnd/DragSourceRpc.java
@@ -0,0 +1,35 @@
+/*
+ * Copyright 2000-2016 Vaadin Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package com.vaadin.shared.ui.dnd;
+
+import com.vaadin.shared.communication.ServerRpc;
+
+/**
+ * RPC for firing server side event when client side dragstart event happens on
+ * drag source.
+ */
+public interface DragSourceRpc extends ServerRpc {
+
+    /**
+     * Called when dragsource event happens on client side.
+     */
+    public void dragStart();
+
+    /**
+     * Called when dragend event happens on client side.
+     */
+    public void dragEnd();
+}
diff --git a/shared/src/main/java/com/vaadin/shared/ui/dnd/DragSourceState.java b/shared/src/main/java/com/vaadin/shared/ui/dnd/DragSourceState.java
new file mode 100644
index 0000000000..aeb4dd816b
--- /dev/null
+++ b/shared/src/main/java/com/vaadin/shared/ui/dnd/DragSourceState.java
@@ -0,0 +1,55 @@
+/*
+ * Copyright 2000-2016 Vaadin Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package com.vaadin.shared.ui.dnd;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import com.vaadin.shared.communication.SharedState;
+
+/**
+ * State class containing parameters for DragSourceExtension.
+ */
+public class DragSourceState extends SharedState {
+
+    /**
+     * Event identifier for dragend event.
+     */
+    public static final String EVENT_DRAGEND = "dragend";
+
+    /**
+     * Event identifier for dragstart event.
+     */
+    public static final String EVENT_DRAGSTART = "dragstart";
+
+    /**
+     * {@code DataTransfer.effectAllowed} parameter for the drag event.
+     */
+    public EffectAllowed effectAllowed = EffectAllowed.UNINITIALIZED;
+
+    /**
+     * {@code DataTransfer.types} parameter. Used to keep track of data formats
+     * set for the drag event.
+     */
+    public List<String> types = new ArrayList<>();
+
+    /**
+     * Used to store data in the {@code DataTransfer} object for the drag event.
+     */
+    public Map<String, String> data = new HashMap<>();
+}
diff --git a/shared/src/main/java/com/vaadin/shared/ui/dnd/DropEffect.java b/shared/src/main/java/com/vaadin/shared/ui/dnd/DropEffect.java
new file mode 100644
index 0000000000..5056ecfd78
--- /dev/null
+++ b/shared/src/main/java/com/vaadin/shared/ui/dnd/DropEffect.java
@@ -0,0 +1,41 @@
+/*
+ * Copyright 2000-2016 Vaadin Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package com.vaadin.shared.ui.dnd;
+
+/**
+ * Used to specify the drop effect to use on dragenter or dragover events.
+ */
+public enum DropEffect {
+    /**
+     * A copy of the source item is made at the new location.
+     */
+    COPY,
+
+    /**
+     * An item is moved to a new location.
+     */
+    MOVE,
+
+    /**
+     * A link is established to the source at the new location.
+     */
+    LINK,
+
+    /**
+     * The item may not be dropped.
+     */
+    NONE
+}
diff --git a/shared/src/main/java/com/vaadin/shared/ui/dnd/DropTargetRpc.java b/shared/src/main/java/com/vaadin/shared/ui/dnd/DropTargetRpc.java
new file mode 100644
index 0000000000..dd21278277
--- /dev/null
+++ b/shared/src/main/java/com/vaadin/shared/ui/dnd/DropTargetRpc.java
@@ -0,0 +1,42 @@
+/*
+ * Copyright 2000-2016 Vaadin Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package com.vaadin.shared.ui.dnd;
+
+import java.util.List;
+import java.util.Map;
+
+import com.vaadin.shared.communication.ServerRpc;
+
+/**
+ * RPC for firing server side drop event when client side drop event happens on
+ * drop target.
+ */
+public interface DropTargetRpc extends ServerRpc {
+
+    /**
+     * Called when drop event happens on client side.
+     *
+     * @param types
+     *         Data types that are present in {@code data} map in the same order
+     *         as found in {@code DataTransfer.types}.
+     * @param data
+     *         Contains data from {@code DataTransfer} object.
+     * @param dropEffect
+     *         Drop effect set for the drop target where drop happened.
+     */
+    public void drop(List<String> types, Map<String, String> data,
+            DropEffect dropEffect);
+}
diff --git a/shared/src/main/java/com/vaadin/shared/ui/dnd/DropTargetState.java b/shared/src/main/java/com/vaadin/shared/ui/dnd/DropTargetState.java
new file mode 100644
index 0000000000..3021c0bd6b
--- /dev/null
+++ b/shared/src/main/java/com/vaadin/shared/ui/dnd/DropTargetState.java
@@ -0,0 +1,38 @@
+/*
+ * Copyright 2000-2016 Vaadin Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package com.vaadin.shared.ui.dnd;
+
+import com.vaadin.shared.communication.SharedState;
+
+/**
+ * State class containing parameters for DropTargetExtension.
+ */
+public class DropTargetState extends SharedState {
+    /**
+     * {@code DataTransfer.dropEffect} parameter for the drag event
+     */
+    public DropEffect dropEffect;
+
+    /**
+     * Criteria script to allow dragOver event on the element
+     */
+    public String dragOverCriteria;
+
+    /**
+     * Criteria script to allow drop event on the element
+     */
+    public String dropCriteria;
+}
diff --git a/shared/src/main/java/com/vaadin/shared/ui/dnd/EffectAllowed.java b/shared/src/main/java/com/vaadin/shared/ui/dnd/EffectAllowed.java
new file mode 100644
index 0000000000..2ff9f21980
--- /dev/null
+++ b/shared/src/main/java/com/vaadin/shared/ui/dnd/EffectAllowed.java
@@ -0,0 +1,81 @@
+/*
+ * Copyright 2000-2016 Vaadin Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package com.vaadin.shared.ui.dnd;
+
+/**
+ * Used to specify the effect that is allowed for a drag operation.
+ */
+public enum EffectAllowed {
+    /**
+     * The item may not be dropped.
+     */
+    NONE("none"),
+
+    /**
+     * A copy of the source item may be made at the new location.
+     */
+    COPY("copy"),
+
+    /**
+     * An item may be moved to a new location.
+     */
+    MOVE("move"),
+
+    /**
+     * A link may be established to the source at the new location.
+     */
+    LINK("link"),
+
+    /**
+     * A copy or move operation is permitted.
+     */
+    COPY_MOVE("copyMove"),
+
+    /**
+     * A copy or link operation is permitted.
+     */
+    COPY_LINK("copyLink"),
+
+    /**
+     * A link or move operation is permitted.
+     */
+    LINK_MOVE("linkMove"),
+
+    /**
+     * All operations are permitted.
+     */
+    ALL("all"),
+
+    /**
+     * Default state, equivalent to ALL
+     */
+    UNINITIALIZED("uninitialized");
+
+    private final String value;
+
+    EffectAllowed(String value) {
+        this.value = value;
+    }
+
+    /**
+     * Get the string value that is accepted by the client side drag event.
+     *
+     * @return String value accepted by the client side drag event.
+     */
+    public String getValue() {
+        return value;
+    }
+}
diff --git a/themes/src/main/themes/VAADIN/themes/valo/shared/_global.scss b/themes/src/main/themes/VAADIN/themes/valo/shared/_global.scss
index 3c4761ad32..441e073dcf 100644
--- a/themes/src/main/themes/VAADIN/themes/valo/shared/_global.scss
+++ b/themes/src/main/themes/VAADIN/themes/valo/shared/_global.scss
@@ -345,6 +345,8 @@ $valo-shared-pathPrefix: null;
 
   @include valo-drag-element;
 
+  @include valo-draggable;
+
   @include valo-tooltip;
 
   @include valo-contextmenu;
diff --git a/themes/src/main/themes/VAADIN/themes/valo/shared/_overlay.scss b/themes/src/main/themes/VAADIN/themes/valo/shared/_overlay.scss
index 1c6f0c6fbc..5b44e94cac 100644
--- a/themes/src/main/themes/VAADIN/themes/valo/shared/_overlay.scss
+++ b/themes/src/main/themes/VAADIN/themes/valo/shared/_overlay.scss
@@ -275,6 +275,12 @@ $v-selection-item-selection-color: $v-selection-color !default;
   }
 }
 
+@mixin valo-draggable {
+  .v-draggable {
+    user-select: none !important;
+  }
+}
+
 /**
  * Outputs the styles for generic dragging ghost elements.
  *
diff --git a/uitest/src/main/java/com/vaadin/tests/dnd/DragAndDropCardShuffle.java b/uitest/src/main/java/com/vaadin/tests/dnd/DragAndDropCardShuffle.java
new file mode 100644
index 0000000000..24c3940737
--- /dev/null
+++ b/uitest/src/main/java/com/vaadin/tests/dnd/DragAndDropCardShuffle.java
@@ -0,0 +1,153 @@
+/*
+ * Copyright 2000-2016 Vaadin Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package com.vaadin.tests.dnd;
+
+import java.util.Optional;
+
+import com.vaadin.event.dnd.DragSourceExtension;
+import com.vaadin.event.dnd.DropTargetExtension;
+import com.vaadin.server.Extension;
+import com.vaadin.server.Page;
+import com.vaadin.server.VaadinRequest;
+import com.vaadin.tests.components.AbstractTestUIWithLog;
+import com.vaadin.ui.Component;
+import com.vaadin.ui.HorizontalLayout;
+import com.vaadin.ui.Label;
+
+public class DragAndDropCardShuffle extends AbstractTestUIWithLog {
+
+    // Data type for storing card position
+    private static final String DATA_INDEX = "index";
+
+    // Create cards
+    private final Label ace = new Label("A");
+    private final Label jack = new Label("J");
+    private final Label queen = new Label("Q");
+    private final Label king = new Label("K");
+
+    // Create desk
+    private final HorizontalLayout desk = new HorizontalLayout();
+
+    @Override
+    protected void setup(VaadinRequest request) {
+
+        // Create UI and add extensions
+        desk.addComponents(ace, jack, queen, king);
+
+        ace.setStyleName("card");
+        addDragSourceExtension(ace);
+        addDropTargetExtension(ace);
+
+        jack.setStyleName("card");
+        addDragSourceExtension(jack);
+        addDropTargetExtension(jack);
+
+        queen.setStyleName("card");
+        addDragSourceExtension(queen);
+        addDropTargetExtension(queen);
+
+        king.setStyleName("card");
+        addDragSourceExtension(king);
+        addDropTargetExtension(king);
+
+        addComponent(desk);
+
+        // Add styling
+        setStyle();
+    }
+
+    private void addDragSourceExtension(Label source) {
+        // Create and attach extension
+        DragSourceExtension dragSource = new DragSourceExtension();
+        dragSource.extend(source);
+
+        // Set component position as transfer data
+        dragSource.setTransferData(DATA_INDEX,
+                String.valueOf(desk.getComponentIndex(source)));
+
+        // Add listeners
+        dragSource.addDragStartListener(event -> {
+            event.getComponent().addStyleName("dragged");
+            log(((Label) event.getComponent()).getValue() + " dragstart");
+        });
+
+        dragSource.addDragEndListener(event -> {
+            event.getComponent().removeStyleName("dragged");
+            log(((Label) event.getComponent()).getValue() + " dragend");
+        });
+    }
+
+    private void addDropTargetExtension(Label target) {
+        // Create and attach extension
+        DropTargetExtension dropTarget = new DropTargetExtension();
+        dropTarget.extend(target);
+
+        // Add listener
+        dropTarget.addDropListener(event -> {
+            // Retrieve the source's position
+            int sourceIndex = Integer
+                    .valueOf(event.getTransferData(DATA_INDEX));
+
+            // Find source component
+            Component source = desk.getComponent(sourceIndex);
+
+            // Swap source and target components
+            desk.replaceComponent(target, source);
+
+            // Get DragSource extension for target component and set position data
+            Optional<Extension> targetExt = target.getExtensions().stream()
+                    .filter(e -> e instanceof DragSourceExtension).findFirst();
+            targetExt.ifPresent(extension -> {
+                ((DragSourceExtension) extension).setTransferData(DATA_INDEX,
+                        String.valueOf(desk.getComponentIndex(target)));
+            });
+
+            // Get DragSource extension for source component and set position data
+            Optional<Extension> sourceExt = source.getExtensions().stream()
+                    .filter(e -> e instanceof DragSourceExtension).findFirst();
+            sourceExt.ifPresent(extension -> {
+                ((DragSourceExtension) extension).setTransferData(DATA_INDEX,
+                        String.valueOf(desk.getComponentIndex(source)));
+            });
+
+            log(((Label) source).getValue() + " dropped onto " + ((Label) event
+                    .getComponent()).getValue());
+        });
+    }
+
+    private void setStyle() {
+        Page.Styles styles = Page.getCurrent().getStyles();
+
+        styles.add(".card {"
+                + "width: 150px;"
+                + "height: 200px;"
+                + "border: 1px solid black;"
+                + "border-radius: 7px;"
+                + "padding-left: 10px;"
+                + "color: red;"
+                + "font-weight: bolder;"
+                + "font-size: 25px;"
+                + "background-color: gainsboro;"
+                + "}");
+        styles.add(".v-drag-over {border-style: dashed;}");
+        styles.add(".dragged {opacity: .4;}");
+    }
+
+    @Override
+    protected String getTestDescription() {
+        return "Shuffle cards with pure HTML5 drag and drop";
+    }
+}