Remove support for transfer data type (#8910)

* Remove API for setting arbitrary drag data
* Store the drag source component in the UI

Fixes #8893 

2 files changed, 11 insertions, 24 deletions

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
index 7c3a6363db..766c79e3eb 100644
--- a/shared/src/main/java/com/vaadin/shared/ui/dnd/DragSourceState.java
+++ b/shared/src/main/java/com/vaadin/shared/ui/dnd/DragSourceState.java
@@ -15,11 +15,6 @@
  */
 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;
 
 /**
@@ -41,18 +36,18 @@ public class DragSourceState extends SharedState {
     public static final String EVENT_DRAGSTART = "dragstart";
 
     /**
-     * {@code DataTransfer.effectAllowed} parameter for the drag event.
+     * Data type {@code "text"} for storing data in {@code DataTransfer} object.
      */
-    public EffectAllowed effectAllowed = EffectAllowed.UNINITIALIZED;
+    public static final String DATA_TYPE_TEXT = "text";
 
     /**
-     * {@code DataTransfer.types} parameter. Used to keep track of data formats
-     * set for the drag event.
+     * {@code DataTransfer.effectAllowed} parameter for the drag event.
      */
-    public List<String> types = new ArrayList<>();
+    public EffectAllowed effectAllowed = EffectAllowed.UNINITIALIZED;
 
     /**
-     * Used to store data in the {@code DataTransfer} object for the drag event.
+     * Used to store text data in {@code DataTransfer} object for the drag
+     * event.
      */
-    public Map<String, String> data = new HashMap<>();
+    public String dataTransferText;
 }
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
index 917bee7d6c..b74fd3a949 100644
--- a/shared/src/main/java/com/vaadin/shared/ui/dnd/DropTargetRpc.java
+++ b/shared/src/main/java/com/vaadin/shared/ui/dnd/DropTargetRpc.java
@@ -15,9 +15,6 @@
  */
 package com.vaadin.shared.ui.dnd;
 
-import java.util.List;
-import java.util.Map;
-
 import com.vaadin.shared.communication.ServerRpc;
 
 /**
@@ -32,16 +29,11 @@ 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 dataTransferText
+     *         Data of type {@code "text"} from the {@code DataTransfer}
+     *         object.
      * @param dropEffect
      *         Drop effect set for the drop target where drop happened.
-     * @param dragSourceId
-     *         Drag source component connector's ID.
      */
-    public void drop(List<String> types, Map<String, String> data,
-            DropEffect dropEffect, String dragSourceId);
+    public void drop(String dataTransferText, DropEffect dropEffect);
 }