Make it possible to drop things on top of Grid rows (#8747)

Fixes #8400

1 files changed, 72 insertions, 0 deletions

diff --git a/server/src/main/java/com/vaadin/ui/GridDropTargetExtension.java b/server/src/main/java/com/vaadin/ui/GridDropTargetExtension.java
new file mode 100644
index 0000000000..bf75e26783
--- /dev/null
+++ b/server/src/main/java/com/vaadin/ui/GridDropTargetExtension.java
@@ -0,0 +1,72 @@
+/*
+ * 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.ui;
+
+import com.vaadin.event.dnd.DropTargetExtension;
+import com.vaadin.event.dnd.grid.GridDropEvent;
+import com.vaadin.event.dnd.grid.GridDropListener;
+import com.vaadin.shared.Registration;
+import com.vaadin.shared.ui.grid.GridDropTargetExtensionRpc;
+import com.vaadin.shared.ui.grid.GridDropTargetExtensionState;
+
+/**
+ * Makes the rows of a Grid HTML5 drop targets. This is the server side
+ * counterpart of GridDropTargetExtensionConnector.
+ *
+ * @param <T>
+ *         Type of the Grid bean.
+ * @author Vaadin Ltd
+ * @since
+ */
+public class GridDropTargetExtension<T> extends DropTargetExtension<Grid<T>> {
+    public GridDropTargetExtension(Grid<T> target) {
+        super(target);
+    }
+
+    @Override
+    protected void registerDropTargetRpc(Grid<T> target) {
+        registerRpc((GridDropTargetExtensionRpc) (dataTransferText, rowKey) -> {
+            GridDropEvent<T> event = new GridDropEvent<>(target,
+                    dataTransferText, getUI().getActiveDragSource(), rowKey);
+
+            fireEvent(event);
+        });
+    }
+
+    /**
+     * Attaches drop listener for the current drop target. {@link
+     * GridDropListener#drop(GridDropEvent)} 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(GridDropListener<T> listener) {
+        return addListener(GridDropEvent.class, listener,
+                GridDropListener.DROP_METHOD);
+    }
+
+    @Override
+    protected GridDropTargetExtensionState getState() {
+        return (GridDropTargetExtensionState) super.getState();
+    }
+
+    @Override
+    protected GridDropTargetExtensionState getState(boolean markAsDirty) {
+        return (GridDropTargetExtensionState) super.getState(markAsDirty);
+    }
+}